US3210404A - Di-neoalkyl beta, beta, beta1, beta1-tetraloweralkyl-substituted alkylene dicarboxylates - Google Patents

Description

United States Patent DI NEOALKYL 6,13,5 ,5 TETRALOWERALKYL- SUBSTITUTED ALKYLENE DICARBOXYLATES Albert M. Durr, Jr. and Harold H. Eby, Ponca City,

Okla and Melvin S. Newman, Columbus, Ohio, assignors to Continental Oil Company, Ponca City, Okla a corporation of Delaware No Drawing. Original application July 16, 1962, Ser. No. 210,198. Divided and this application Jan. 12, 1965, Ser. No. 425,083

2 Claims. (Cl. 260-485) This application is a division of application Serial No. 210,198, filed July 16, 1962, which was a continuationin-part of application Serial No. 747,587, filed July 10, 1958, and now abandoned.

This invention relates to ester-type materials which are suitable for use as synthetic lubricants. More particularly, the invention relates to ester-type materials which are derived from acids in which the carbon atom alpha or beta to the carboxyl group is completely substituted with acyclic alkyl groups. Preferably, the sub stituted carbon atom is the alpha carbon atom.

Military use of turbojet and turboprop aircraft engines has led to a need for specialized engine lubricants. These lubricants must permit starting at very low temperatures encountered in arctic bases. They also must have adequate lubricity and stability at very elevated temperatures. Modern engines have exceedingly high power for their size and put a severe heat stress on the lubricant.

The mineral lubricating oils which possess satisfactory low temperature viscosities have generally been found to have flash points that are dangerously low and high temperature viscosities that are below those required. In other words, when the mineral oil is thin enough at low temperatures, it is too thin and too volatile at higher temperatures. In addition, conventionally refined mineral oils deteriorate too rapidly at high operating temperatures, even when compounded with the best available antioxidants.

needed for these turbine-type engines, synthetic lubricants have been developed. Esters represent a class of materials which have attracted unusual interest as synthetic lubricants. Diesters are a preferred class of esters. These materials are generally characterized by high viscosity indexes and flash points and lower pour points than mineral oils of a corresponding viscosity.

While the diesters offer many outstanding properties which enable them to be used as lubricants for turbojet and turboprop engines, there remain characteristics in which they may be improved. Two such characteristics are thermal stability and hydrolytic stability,

In the more recent turbines, the normal hearing temperatures during operation reach as high as 475 F. With bearings next to the turbine wheel, a soak-back effect occurs following shutdown. Heat accumulated in the turbine wheel disk flows into the cooler turbine bearings when the oil flow is stopped at time of shutdown. This may add another 100 to 150 F. for a brief period following shutdown. The resulting temperatures are higher than can be withstood by conventional diesters, regardless of compounding with additives. Lack of thermal stability in these materials results in (a) engine deposits and (b) physical loss of lubricant due to partial volatilization of decomposition products.

Since all oil systems in aircraft collect small amounts of Water from time to time, a diester lubricant should have hydrolytic stability. Lack of hydrolytic stability results in formation of volatile alcohols and corrosive 40 Recently, in an effort to obtain the superior lubrlcants acids. Currently availaible diesters are not adequately stable.

Broadly stated, the present invention relates to estertype materials which are derived from organic carboxylic acids in which the carbon atom alpha or beta to the carboxyl group is completely substituted with acyclic alkyl groups. In one embodiment the invention relates to diesters which are derived from dicarboxylic acids in which the carbon atoms alpha to each of the carboxyl groups is completely substituted with acyclic alkyl groups, and from either conventional monohydroxy alcohols or from monohydroxy alcohols in which the beta carbon atom thereof is completely substituted with alkyl groups or fluorine atoms. In a further embodiment. the invention relates to diesters which are derived from dicarboxylic acids in which the carbon atoms beta to each of the carboxyl groups is completely substituted with acyclic alkyl groups and from monohydroxy alcohols in which the beta carbon atom thereof is completely substituted with either acyclic alkyl groups or fluorine atoms. In another embodiment the invention relates to esters prepared from monobasic acids in which the carbon atom adjacent to the carboxyl group is completely substituted with acyclic alkyl groups and polyhydroxy alcohols in which the beta carbon thereof is completely substituted with acyclic alkyl groups. In still another embodiment the invention relates to the novel dicarboxylic acids in which the carbon atoms alpha or beta to each of the carboxyl groups is completely substituted with acyclic alkyl groups. In yet another embodiment the invention relates to a process for preparing the afore-mentioned dicarboxylic acids. In yet still another embodiment the invention relates to complex esters which are prepared from (a) the afore-mentioned dicarboxylic acids, (b) the afore-mentioned monobasic acids, (c) the afore-mentioned polyhy'droxy alcohols and (d) the afore-mentioned monohydroxy alcohols.

Before proceeding to a description of the suitable starting materials for these ester-type materials, it may be well to set forth an explanation of the heory associated with the function of these materials. While we do not wish to be bound by this explanation, we believe the theory is as follows:

Thermal degradation of esters formed from aliphatic alcohols and aliphatic acids is initiated at the carbonyl oxygen and results in the formation of olefin and acid. This degradation arises from electron migration after formation of an unstable ring structure. To form this intermediate ring there must be hydrogen atoms in the alcohol portion of the ester which are in the sixth atom position from the carbonyl oxygen. These hydrogen atoms must also be coplanar to the carbonyl group or must have rotational freedom if ring formation is to occur. The action is indicated by the following diagram:

Esters in which the six positions of the alcohol portion are completely substituted with alkyl groups prea vent thermal elimination through this mechanism because the formation of the above foregoing ring structure is not possible and no hydrogens are available in the six position for transfer.

Alkyl groups on the alpha carbon of the acid portion of an ester molecule sterically hinder and reduce the availability of the carbonyl oxygen for attack by oxygen, hydrogen, acids, or bases. In other words, the presence of such alkyl groups improves the hydrolytic stability of the ester molecule. The greater the size of the alkyl substituent, the greater would be the hindrance and, accordingly, resistance to hydrolysis. Methyl groups in the alpha position to the carbonyl carbon meet the minimum requirements.

Alcohols with alkyl groups or fluorine atoms on the carbon atom beta to the hydroxyl group, and acids in which the carbon atoms either alpha or beta to the carboxyl groups are completely substituted with alkyl groups, are referred to as hindered alcohols and acids. Esters prepared from alcohols and acids, both of which are hindered, possess both thermal and hydrolytic stability. If only the alcohol is hindered, the ester possesses only thermal stability. If only the acid is hindered, the ester possesses only hydrolytic stability.

We have found that substitution only on the beta carbon atoms of the dicarboxylic acid does not produce a noticeable or measurable effect on hydrolytic stability. Still further, we have found that esters prepared from hindered alcohol and dicarboxylic acids in which the carbon atoms, either alpha or beta to the carboxyl groups, are completely substituted with alkyl groups exhibit thermal stability greater than is shown when only the alcohol is hindered. This discovery is surprising.

Before giving specific examples of the products and processes of the present invention it may be well at this time to describe the nature of the materials used and the processes involved.

In order to set forth clearly the nature of the present invention the term ester as used herein and in the claims refers to the product derived by reacting an organic carboxylic acid with an organic hydroxy compound.

The hindered dibasic acids of the present invention have one of the following formulas:

wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms, n is an integer varying from 1 to 10, and n is an integer varying from 1 to 9.

Examples of suitable dibasic acids in which the carbon atom alpha to the carboxyl group is completely substituted with acyclic alkyl groups are the following:

Suberrc acids:

2,2,7,7-tetraethyl* 2,7-dimethyl-2,7-diethyl 2,7-dimethyl-2,7-dipropyl* 2,7-diethyl-2,7-dipropyl 2,7-diethyl-2,7-dibutyl 2,2,7,7-tetramethyl* 2,2,7,7-tetrapropyl 2,2,7,7-tetrabutyl Azelaic acids:

2,2,8,8tetraethyl* 2,8-dimethyl-2,8-diethyl* 2,8-dimethyl-2,8-dipropyl* 2,8-diethyl-2,8-dipropyl 2,8-diethyl-2,8-dibutyl* 2,2,8,8-tetramethyl 2,2,8,8-tetrapropyl 2,2,8,8-tetrabutyl 2,2,8,8-tetraisopropyl 2,2,8,S-tetratertiarybutyl Sebacic acids:

2,2,9,9-tetraethyl* 2,9-dimethyl-2,9-diethyl 2,9-dimethyl-2,9-dipropyl* 2,9-diethyl-2,9-dipropyl 2,9-diethyl-2,9-dibutyl* 2,2,9,9-tetramethyl* 2,2,9,9-tetrapropyl 2,2,9,9-tetrabuty1 Examples of suitable dibasic acids in which the carbon atom beta to the carboxyl group is completely substituted with acyclic alkyl groups are the following:

Beta acids:

3,3-dimethyl glutaric acid 3,3,5 ,5 -tetramethyl pimelic acid 3,3,6,6-tetramethyl suberic acid* 3,3,6,6-tetraethyl suberic acid 3,6-dimethyl-3,6-diethyl suberic acid" 3,3,7,7-tetramethy1 azelaic acid 3,3,8,8-tetramethyl sebacic acid Of the suitable acids listed above, the ones indicated with an asterisk are preferred. Of the preferred acids, the ones indicated with a double asterisk are more preferred.

Diesters having improved hydrolytic stability are exceedingly difficult to prepare directly from hindered acids because the hindrance impedes reaction with the alcohol. We have prepared these diesters from the acid chloride of the hindered acid and the sodium salt of the alcohol used.

Diesters prepared from hindered alpha-substituted dibasic acids and conventional alcohols have the following formula:

wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms, R is an acyclic alkyl group containing from 1 to carbon atoms and n is an integer varying from 1 to 10. Examples of suitable conventional alcohols are the following:

n-Butanol n-Dodecanol n-Hexanol n-Tridecanol n-Octanol* n-Hexadecanol n-Decanol*= n-Octadecanol Z-ethylhexanol 2-ethy1 butanol Isooctanol Isodecanol Of the suitable alcohols listed above, the ones indicated with an asterisk are preferred.

Diesters prepared from hindered dibasic acids and hindered alcohols have the following formula:

where A is selected from wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms, R is an acyclic alkyl group containing from2 to 10 carbon atoms, X is either fluorine or an acyclic fiuoroalkyl group containing from 1 to 10 carbon atoms, where B is selected from:

wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms, n is an integer varying from 1 to 10, and n is an integer varying from 1 to 9.

The hindered alcohols of the present invention have one of the following formulas:

where R is an acylic al-kyl group containing from 1 to 4 carbon atoms, R is an acyclic alkyl group containing from 2 to 10 carbon atoms, and X is either fluorine or an acyclic fluoroalkyl group containing from 1 to 10 carbon atoms.

Examples of suitable hindered alcohols are the following:

2,2-dimethyl-1-pentanol* 2,2-diethyl-1 butanol* 2,2dimethyl- 1-heXanol* 2,2-dimethyl-1-butanol Z-methyl-Z-ethyll-octanol 2,2,4-trimethyl-l-pentanol 2,2-dimethyl-1-octanol* 2,2dimethyl-l -decanol* Z-methyl-Z-propyld -pentanol 2-ethyl-2-propyl-1-hexanol 2-methyl-2-tertiary amyl-l-butanol 2-methyl-2-isopropyl-1-hexanol 1H,1H,7H-dodecafluoro 1-heptanol 1H,1H,9H-hexadecanefluoro-l-nonanol 1H,1H,1lH-eicosafiuoro-l-undecanol Of the suitable alcohols listed above, the alcohols with acyclic alkyl substituents on the beta carbon atom are preferred. Of these latter alcohols the ones indicated with an asterisk are more preferred.

Some of the hindered alcohols in which the beta carbon atom is completely substituted with alkyl groups are available commercially. The others can be prepared in the laboratory. The preparation of 2,2-dirnethyl-1- hexanol is shown below:

PREPARATION OF 2,2-DIMETHYL-l-HEXANOL 1. Intermediate (1) Sodium triethylmethoxide (C H COH+NaNHg (C2H5)3CON3 (2) Dimethylacetyl chloride (CH CHC(O OH+SOCl (CH CHCO Cl where C(O) is 0:0

(3) Triethylcarbinyl isobutyrate C H CONa+ (CH CHCOC1 3)z l z 5)a 2. 2,2-dimethyl-1-hexan0l The hindered monobasic acids of our invention have the formula:

wherein R R and R are acyclic alkyl groups containing from 1 to 18 carbon atoms. Examples of suitable hindered monobasic acids are the following:

Of the above suitable hindered monobasic acids the ones indicated with an asterisk are preferred.

The hindered polyhydroxy alcohols of our invention have the following formula:

wherein A has a formula selected from the group consisting of:

wherein R, R and R are acyclic alkyl groups containing 1 to 4 carbon atoms and n is an integer varying from 1 to 10.

Examples of suitable hindered polyhydroxy alcohols are the following:

GLYCOLS 1,3-propanediols:

2,2-dimethyl* 2,2-diethyl* 2,2-dipropyl 2,2-dibutyl 2-methyl-2-ethyl* 2-methyl-2-propyl* 2-methyl-2-buty1* 2-ethyl-2-propyl Z-ethyl-Z-butyl 1,6-hexanediols:

2,2,5,5-tetramethyl* 2,6-dimethyl-2,6-diethyl* 2,6-dimethyl-2,6-dipropyl 2,6-dimethyl-2,6-dibutyl 2,6-diethyl-2,6-dipropyl* 2,2,5 ,5 -tetraethyl t2,2,5,5-tetra'butyl 2,5,5-trimethyl-2-propyl-3ethyl 2,2,5,S-tetramethyl-3,4-diethyl 1,7-heptanediols:

2,4,6-trimethyl-2,6-dipropy1 2,2,4, 6,6-pentamethyl-3-ethyl 1,8-octanediols:

2,7,7-trimethyl-2-propyl 2,2,4,5,7,7-hexarnethyl 2,2,7,7-tetramethyl-3-ethyl 2,2,4,7,7-pentamethyl 1,10-decanediols 2,2,9,9-tetramethyl* Of the above suitable hindered polyhydr-oxy alcohols the ones indicated with an asterisk are preferred.

Esters prepared from hindered monobasic acids and polyhydroxy alcohols have improved hydrolytic and thermal stability. These materials have the following formula:

wherein R R and R are acyclic alkyl groups containing from 1 to 18 carbon atoms and where A is selected from the group consisting of:

R4 R4 R: I a I J and |(CH ),,('3- R4 R4 R4 wherein R is an acyclic alkyl group containing from 1 to 4 carbon atoms and n is an integer varying from 1 to 10.

Complex esters can be prepared from the hindered alcohols, hindered dibasic acids, and hindered polyhydroXy alcohols of the present invention. These complex esters possess improved hydrolytic stability. They can be shown diagrammatically as follows:

where A equals hindered monohydroxy alcohol, B equals hindered dibasic acid, and A equals hindered polyhydroxy alcohol; and

where B equals hindered dibasic acid, A equals hindered polyhydroxy alcohol, and D equals hindered monobasic acid.

The hindered dibasic acids per se which form an embodiment of our invention have been described previously.

Our invention relates also to the process for preparing the hindered alpha-substituted dibasic acids. This process can be described as comprising the following steps.

(a) Synthesis of the intermediates (1) Preparation of diethylacetyl chloride:

(C H CHC(O)OH+SOCl (C H CHC(O)CI (2) Preparation of sodium triethylmethoxide:

liq. N H3 (C2H5)3C OH NaNH (C2H5)3C ONa (3) Preparation of triethylcarbinyl Z-ethylbutyrate:

(b) Synthesis of di(triethylcarbinyl) 2,2,8,8-tetraethylazelate Na (C H 1C(O)OC(C2H5)3+ BromomcI-nomcmm OHZCH2C CZH5 2C (O)OC(C2H5)3 CH2 z 2 02 2 5)a (0) Preparation of 2,2,8,8-tetraethylazelaic acid CHzCHzC (02115): (O)OC(C2H5)3 dioxane z z 2 02 O C (0 119 E? I 2 20 (C2 5)2C O OH CH HBCHBC (C2H5)2C O OH While the purpose of this invention is to provide materials which are especially useful in the formulation of lubricants for use in turbojet and turboprop engines, the novel diesters herein described may find use in wide temperature range greases, high temperature heat transfer fluids, hydraulic fluids, and lubricants for precision instrument bearings. The novel diesters of this invention are 9 materials which provide hydrolytic stability to an extent hitherto unknown.

Conventional diesters were used as standards for comparison with the hindered diesters of this invention. Diisooctyl azelate, di-Z-ethylhexyl sebacate, and diisobutyl azelate are commercially available diesters which were used per se. Di-2-ethylhexyl azelate is also commercially available, but the material used was purified by vacuum distilling, to obtain a center cut, and then filtering through alumina. Dl-n-octyl azelate was prepared from commercially available materials. Its preparation is shown in the examples.

In order to disclose the nature of the present invention still more clearly, the following illustrative examples will be given. It is to be understood that the invention is not to be limited to the specific conditions or details set forth in these examples except insofar as such limitations are specified in the appended claims.

Example I.Preparatin of di-n-octyl azelate Apparatus.One-liter, three-necked, round-bottomed flask; Trubore stirrer; thermometer; Barrett water trap; reflux condenser; heating mantle; separatory funnel (two liters).

Procedure-Charged 188.2 grams of azelaic acid, 325.0 grams of l-octanol, 2.0 grams of toluenesulfonic acid, and 150 cc. of benzene to the reaction flask. Heat was applied and stirring commenced. Reflux initially was at 95 C. and continued for 8 hours, at which time the reflux temperature had risen to 110 C. During this period, 36 ml. of water was removed and collected in the water trap. The reaction mixture was then transferred to a Separatory funnel and washed with 2 x 250 ml. portions of 5 percent aqueous sodium carbonate solution. It was then washed with 5 x 250 ml. portions of tap water until the pH (via Hydrion paper) was 7. The crude diester was dried over anhydrous magnesium sulfate and then filtered through a one-inch cake of Hyfio filter aid. The filter aid was washed with 100 ml. of benzene and the benzene was added to the product layer. The crude mixture (653 grams) was charged to a simple vacuum distillation setup. Using a water aspirator, benzene solvent was removed. Using a vacuum pump, a forecut which included excess alcohol was removed at 0.65 mm. Hg up to a vapor temperature of 187 C. At 0.07 mm. Hg 364.0 grams of diester (di-n-octyl azelate) was collected. A cut distilling between 202-235 C. at 0.17 mm. Hg weighed 18.2 grams. The bottoms weighed 7.5 grams. The diester cut was percolated through 104 grams of alumina. The filtrate had an acid number of 1.2 and a saponification number of 269. The acid number was further reduced to 0.02 by percolation through basic ion exchange resin.

Example II.Preparalion of di 2,2-dimethylhexyl azelate Prepared in accordance with synthesis steps outlined in previous discussion.

A pparatus.-Two-liter, three-necked, round-bottom flask; Trubore stirrer; thermometer; Barrett water trap; water-cooled reflux condenser.

Procedure-To the reaction flask were charged 141.8 grams of 2,2-dimethyl-l-hexanol, 104.5 gr'amsof azelaic acid, 250 cc. of benzene, and 2 grams of p-toluenesulfonic acid. This mixture was heated with stirring at reflux for 8 hours, during which time 20.5 cc. of water was collected in the Barrett trap. In an additional 8 hours of heating at reflux with stirring, no additional water was collected. The reaction mixture was transferred to a separatory funnel and washed with 2 x 100 cc. portions of sodium carbonate solution which emulsified; but after standing overnight, it separated when 400 cc. of ether was added. This ethereal layer was then washed with 2 x 100 cc. portions of water, dried over calcium sulfate, and filtered through a three-inch cake grams of alumina). The alumina was washed with 150 m. of ether. The ethereal filtrate and the ether wash of the alumina were combined and stripped of benzene and ether up to 100 C. on a water aspirator. At 0.14 mm. Hg using a vacuum fractionation setup, 163.4 grams of di-2,2-dimethylhexyl azelate was separated between 176191 C. vapor temperature. A forecut (10 grams) and the still bottoms (14 grams) were also obtained. The yield of the diester based on the alcohol charged is 72.5 percent. The acid number of the distilled diester was 0.76. The acid number was reduced to 0.04 by percolation through basic ion exchange resin.

Example lII.Preparati0n of di-2,2-diethylbulyl azelate Materials Moles Grams 2,2-diethyl-1-butanol O. 121. 5 Azelaic acid 89. 4 Benzene (250 cc.) p-Toluenesulfonie a 2.0

ther- (650 cc.)

Prepared in accordance with synthesis steps outlined in previous discussion.

A pparatus.-Same as in Example II.

Pr0cedure.-The procedure was the same as used in Example II. A yield of 148.3 grams (76.5% of theory based on alcohol charged) of product was obtained. The boiling range of the product was 185-192 C. at 0.12 mm. of mercury. The distilled diester had an acid number of 0.97. The acid number was reduced to 0.02 by percolation through basic ion exchange resin.

Example I V.-Preparati0n of di-2,2-dimetizylamyl azelate Materials Moles Grams Archie acid 0.5 94 2,2-dimethyl-1-pentanol 1. l 128 p-Toluenesulfonic acid 2 Ben ene (200 cc.)

, percent by volume with pentane, was percolated through alumina and then a 12-inch column of the basic ion exchange resin (IR45). Pentane was removed up to C. at .1 mm. Hg. The acid number of this undistilled diester was 0.03. It weighed 170 grams (88.5 percent yield).

The second batch was prepared using the same procedure except that the diester was distilled. The di(2, Z-dimethylamyl) azelate distilled between 180 C at .1 mm. Hg pressure.

The acid number of the dis- (A) Preparation of 2,2,8,8-tetraethylazelaoyl chloride Materials Moles Grams 2,2,8,8-tetraethylazelaic acid 1 Thionyl chloride Benzene (solvent) 1 Prepared in accordance with synthesis steps outlined in previous discussion.

Apparatus.Two-liter, three-necked flask; Trubore stirrer; reflux condenser; thermometer.

Prcedurc.Charged 76.7 grams of thionyl chloride to the dry reaction flask along with 84.7 grams of 2,2, 8,8-tetraethylazelaic acid and 450 cc. of benzene. Stirring was commenced and the mixture heated at 78 C. until hydrogen chloride gas evolution ceased (eight hours). The crude mixture was stripped of excess thionyl chloride and benzene at atmospheric pressure up to 122 C. pot temperature. On house vacuum at maximum pot temperature of 118 C., remaining traces of light ends were removed. The acyl halide bottoms which solidified on cooling weighed 92 grams (theoretical 95 grams). This product analyzed 17.5 percent C1 (theoretical 21).

(B) Preparation of di(n-octyl)-2,2,8,8-tetraethylazelate Materials Moles Grams Ferric nitrate (catalyst for amide prepara- Apparatus.Two-liter, three-necked, round-bottomed flask; Trubore stirrer; Dry Ice-cooled condenser; bubble counter; drying tube; dropping funnel.

Procedure.--Charged 1,000 cc. of ammonia to the dry nitrogen-flushed reaction flask; then 0.5 gram of sodium metal was added. After the solution turned blue, the liquid was blown with dry air until the color was discharged; then 1.0 gram of ferric nitrate was added. Stirring was commenced, and the remaining 22.2 grams of sodium metal was added in small portions over a period of 2.0 hours. The temperature of the reaction flask was held at -35 C. Ten minutes after the addition of the sodium was completed, the blue color was discharged. To this mixture was added dropwise 128.5 grams of l-octanol diluted with 300 cc. of dry ether. After the final addition of l-octanol, an additional 200 cc. of dry ether was added. Ammonia was allowed to evaporate overnight; then nitrogen was blown through the pot mixture, which was heated on a steam bath for five hours. During this period, 500 cc. of ether was added. Next, 166.2 grams of 2,2,8,8-tetraethylazelaoyl chloride in 300 cc. of dry ether was added at such a rate as to maintain constant reflux and control the reaction. Poststirring was continued for three hours. Ice water (500 cc.) was added cautiously over 30 minutes. The mixture was filtered to remove a small quantity of flocculent which hampered separation of the water and ether layers. The two layers were then separated and the ether Wash of the aqueous layer was combined with the ether layer. The ether layer was Washed with 2 x 200 cc. portions of percent sodium hydroxide and finally with water until the wash water was neutral to pHydrion paper. The ether layer was filtered through a one-inch cake of Hyflo filter aid and dried over calcium sulfate. Ether was removed by heating to 60 C. at atmospheric pressure after filtering through grams of alumina. The crude diester was charged to a vacuum distillation setup and stripped up to 200 C. at 0.1 mm. Hg pressure. The maximum vapor temperature during this period was 68 C. Overhead weighed 16.7 grams. The bottoms product Weighed 232.5 grams. The product diester was diluted 50 percent by volume with pentane and percolated through 180 grams of alumina followed by a 12-inch column of basic ion exchange resin (IR-45). Both columns were flushed with pentane and the wash added to the eflluent diester. Pentane was removed up to C. at 0.1 mm. Hg pressure. The product diester weighed 177.5 grams. This product had an acid number of 0.02 and analyzed 75.0 percent carbon (theoretical 75.7) and 12.2 percent hydrogen (theoretical 12.2).

Example VI.Prcparation of di-2,.2-dimethylamyl-2,2, 8,8-tetmethylazelate (A) Preparation of 2,2,8,B-tetraethylazelaoyl chloride 1 Prepared in accordance with synthesis steps outlined in previous discussion.

Apparatus.Two liter, three-necked flask; Trubore stirrer; reflux condenser; thermometer.

Procedure.Charged grams of thionyl chloride to the dry reaction flask along with 154 grams of 2,2,8,8- tetraethylazelaic acid in 500 cc. of benzene. Stirring was commenced, and the mixture was heated at 78 C. until hydrogen chloride gas evolution ceased (12 hours). The crude mixture was stripped of excess thionyl chloride and benzene at atmospheric pressure up to 125 C. pot temperature. On house vacuum at maximum pot temperature of 118 C., remaining traces of light ends were removed. The acyl halide bottoms weighed grams (theoretical 174 grams).

(B) Preparation of di-(2,2-dimethylamyl)-2,2,8,8-tetraethylazelate Apparatus.Two liter, three-necked flask; Trubore stirrer; Dry Ice-cooled condenser; bubble counter; drying tube; dropping funnel.

Procedure-Charged 1,000 cc. of ammonia to the dry nitrogen-flushed reaction flask; then 0.5 gram of sodium metal was added. After the solution turned blue, the liquid was blown with dry air until the color was discharged. One gram of ferric nitrate was added. Stirring was commenced, and the remaining 22.5 grams of sodium was added in small portions over a period of one hour. The temperature of the reaction flask was held at 35 C. Ten minutes after the addition of sodium was completed, the blue color was discharged. To this mixture was added dropwise 116 grams of 2,2-dimethylpentanol diluted with 300 cc. of dry ether. After the final addition of 2,2-dirnethylpentanol, ammonia was allowed to evaporate overnight. Nitrogen was blown through the reaction mixture, which was heated on a steam bath for six hours. Two hundred cc. of ether was added followed by 170 grams of 2,2,8,8-tetraethylazelaoyl chloride in 300 cc. of dry ether at such a rate as to maintain constant reflux and control the reaction.

13 Poststirring was continued for three hours at full reflux. Ice water (750 cc.) was added cautiously over /2 hour. The mixture was filtered to remove fluocculent material and transferred to a separatory funnel in which two tube removed. The U-tube was then inserted, flushed with nitrogen, and a slight positive nitrogen pressure allowed to remain. The tube was immersed in an aluminum block bath and heated to 550 C. for 48 hours.

layers formed. The water layer was removed and washed 5 The acid numbers were then determined by means of a with 200 cc. of ether and the ether wash combined with Precision Automatic Titrator, using AST M procedure the ether layer. The ether layer was washed with Water D66454. until the resulting water wash was neutral to pHydrion In calculating the percent decomposition, as shown in paper. The ether layer was dried overnight over calcium Table III, the saponification number was assumed to be sulfate, filtered through alumina, and stripped of ether equivalent to 100 percent decomposition.

O up to 60 C. at atmosphericpressure. The cmde d ester HydrOlyn-c stability testing was charged to a vacuum distillation setup and stripped up to 192 Q at 025 mm Hg pressure, Th maximum Timed sapomfication numbers were made on both the vapor t mperature was 23 C. The product diester (botreference diesters and the hindered diesters. The time toms) was diluted 50 percent by volume with pentane Intervals Chosen hour, 2 hours, 4 hours, 21111 d percolated h h a 124 b Column f b i i 24 hours. The saponification numbers were determined exchange resin (IR-45). The column was washed with 115mg ASTM Procedure pentane and the washings combined with the product- Physical tests containing layer. Pentane was removed up to 115 C. v at 0.3 mm Hg pressure The product Weighed 198.5 The various physical tests conducted used standard grams. The acid number of the diester was 0.64. ASTM Procedures ABLE I.ANALYTICAL DATA ON HINDERED ALC TESTING PROCEDURES (EXAMPLES IVI) T HOLS AND ACID 0F EXAMPLES 0 Thermal stability testing 25 Boiling The thermal stability of each of the esters prepared Melting Boilil lg p0int.C. Acid N0. was determined using a simple test. A 25-ml. sample of (Lltemme) the ester to be tested was charged to a tube cm. long, 1 25 cm. in diameter, fitted With a side arm 8 cm. from %f EH36 233;? the top of the tube to which was attached through a 30 22d, th 11 75 H4 82 U4 standard taper joint a U-tube containing mercury. The i gif I fi top of the test tube was fitted with a 24/40 standard i g *93 5 H 2 taper joint in which was fitted a stopcock with an S-mm. mm g g ID. tube e.tendin inside the test u x E k t be to i 10 cm JACS,55,1121(1933). of the bottom. T e stopcoc was opened, nitrogen gas 35 1103,78, 5415 was introduced, and the testing tube flushed w1th the U- 3 Gauge not Cahbtated- TABLE II PHYSICAL PROPERTIES OF DIESTERS SHOWN IN EXAMPLES I-VI Viscosities Refractive Example Viscosity ASTM Density index at Number Diester index slope at 25 C. 25 0.,

Cs. at Cs. at Cs. at NaD -40 F. 100 F. 210 F Conventional;

Diisooctyl azelate 1, 285 12. 54 3. 38 164 0. 686 0. 9131 1. 4488 D1-2-etl1yll1exyl sebacate. l, 400 12. 80 3. 34 154 0.706 0. 9106 1. 4492 Diisobutyl azelate- 254 5. 58 1. 1 0.802 0.9281 1. 4348 I Di-n-oetyl azelate- Solid 11. 32 3. 25 175 0.674 0. 9091 1. 4472 Di-Z-ethylhexyl azelate 1, 242 10.96 2. 99 145 0. 676 0. 9135 1. 4481 Hindered:

Di-2,2-dimethylhexyl azelate 4, 722 15. 90 3. 65 133 0.725 0. 9093 1. 4471. Di-2,2-diethylbutyl azelate s, 343 21. 03 4. 43 1, 414 0. 700 0. 9323 1. 4555 Di- 2,2-dimethylamyl azelate (redistilled) 3, 140 13. 26 3. 23 125 0. 736 0. 9151 1. 4451 D1-n-octyl-2,2,8,8-tetraethylazelate Not run 43.27 5. 33 104 0. 736 0.9082 1.4560 Di-2,2-dimethylamyl-2,2,8,8-tetraethyl azelate Not run 118.00 8. 62 0.832 0.9113 1.4545

TABLE TIL-THERMAL STABILITY STUDIES (EXAMPLES IVI) [25 n11. sample heated in nitrogen atmosphere for 48 hours at 550 F.]

Acid No. after- Percent 2 decomposition Saponifica- Example Diester Acid No. tion Num- Number (Before) her, mg.

Run No. 1 Run N0. 2 Run No. 1 Run N0. 2 KOH/gm.

Conventional:

Diisooctyl azelate 0. 02 72 26. 5 34. 9 272 Di-2-ethylhexyl sebacate. 0. 04 43 53 16.2 19. 9 266 Diisobutyl azelate 0. 01 57 61 15. 5 16. 6 368 i I Di-n-octylazelate 0.03 49 67 17.8 24.4 275 Di-Z-etliylhexyl azelate 0. 07 47 40 17. 3 14. 8 271 Hindered:

Di-2,2-di1nethylhexyl azelate 0. 04 4. 4 4. 9 1. 6 1.8 273 Di-2,2-diethyll)utyl azelate. 0. 02 7. 1 5. 9 2. 6 2. 1 275 Di-2,2-di1nethylarnyl azelate- 0. 01 13 13 4. 4 4. 4 295 Di-n-octyl-2.2,8,8-tetraethyl azela 0. 03 56 20.2 3 214 Di-2,2id1;metl1ylamyl-2,2,8,8-tetraethyl 0. 04 8 3.5 3 226 1 Acid number in mg. KOH/grn. 2 decomposition is equal to saponification number. 3 Theoretical.

TABLE IV.HYDROLYTIO STABILITY STUDIES (EXAMPLES I-VI) Saponifieation Number, Example Acid mg. KOH/gm. Number Diester Number 2 hours 4 hours 24 hours Theoretical Actual (30 minutes) Conventional:

Diisooctyl azelate 0.02 272 272 Di-2-ethylhexyl scbacate 0. 04 262 266 Diisobutyl azelate 0. 01 334 308 Di-n-octyl azelate 0. 03 272 275 Di-Z-ethylhexyl azelate 0.07 272 271 Hindered:

Di-2,2-dimethylhexyl azelate O. 04 272 273 Di-2,2-diethy1butyl azelate 0.02 272 275 Di-2,2-dimethylamyl azelate 0.01 292 296 Di-n-octyl-2,2,8,8-tetraethyl 0. 03 214 18 25 22 33 Di-2,2-dimethylamyl-2,2,8,8-tetraethyl azclate 0. 64 226 19 19 21 76 Example VII.Preparati0n of 2,2,8,8-tetraethylazelaic acid (A) Preparation of 2-ethy1butyryl chloride Materials Mole Moles Quantity,

weight g.

2'ethylbutyric acid 116.16 1, 743 Thionyl chloride, Eastman grade.-." 118. 98 1G. 8 2,000

(B) Preparation of triethylcarbinyl 2-ethylbutyrate Materials Mole Moles Quantity weight Ferric nitrate 1 g. Ammonia, anhydrous 2,000 cc Sodium, purified lump 0 Triethylcarbinol, Eastman grade Z-ethylbutyryl chloride Ether, anhydrous reagents Pr0cedure.Sodiurn amide was prepared from 140 grams of sodium and 2 liters of liquid ammonia, using ferric nitrate as catalyst. Triethylcarbinol (969 grams) in 300 cc. of dry ether was slowly added to the reaction mixture. The ammonia was allowed to evaporate, and the mixture was refluxed in a stream of nitrogen for 12 hours. Approximately one liter of dry ether was added during this time.

A solution of 807 grams of Z-ethylbutyryl chloride in 200 cc. of ether was added dropwise to the reaction mixture. This was then stirred for one hour and heated under reflux for another hour. Water was added to dissolve the solids. The ethereal solution was washed with 10 percent sodium hydroxide, washed with water until neutral, and dried over calcium sulfate. Fractional distillation of the crude mixture yielded 1067 grams (83.5 percent) of triethylcarbinyl Z-ethylbutyrate (RR 102- 105 C. at 10 mm).

(0) Preparation of di-(triethylcarbinyl)2,2,8,8-tetraethylazelate Materials Mole Moles Quantity weight Ferric nitrate 1 g. Ammonia, anhydrous 2,000 cc Triethylcarbinyl 2-ethylbutyrate 214 5 1,067 g 1,5-dibromopentane, Eastman grade 229. 97 2. 5 575 g. Sodium, purified lump 22. 997 5 155 g Ether, anhydrous reagent- 600 cc Procedure-Sodium amide was prepared from 115 grams of sodium and 2 liters of liquid ammonia. Triethylcarbinyl Z-ethylbutyrate (1067 grams) was added dropwise, and the mixture was stirred for 1.5 hours. A solution of 575 grams of dibromopentane in 200 cc. of ether was added dropwise, and stirring was continued for 1.5 hours. More ether (400 cc.) was added, and the ammonia was allowed to evaporate. After refluxing the solution one hour, water was added to dissolve the solids present. The ethereal solution was washed with water until neutral, dried over calcium sulfate, and reduced to small volume under vacuum. The crude residue weighing 1002 grams was hydrolyzed without further purification.

(D) Hydrolysis of di-(tricthylcarbinyl)2,2,8,8-tetraethylazelate Materials Mole Moles Quantity weight Di (triethylcarbinyl)2,2,8,8-tetra- 496 2. 02 1,002 g.

ethylazelate. Hydrochloric acid, concentrated 36. 5 5. 35 450 cc.

reagent. Dioxane, commercial 500 cc Examp le VIII.-Preparation of Z-methyl-Z-ethyl-I- pentanol (A) Preparation of 2-1nethy1pentanoyl chloride Materials Mole weight Moles Grams 2-methylpentanoic acid Thionyl chloride Pr0cedure.To 1457.5 grams of thionyl chloride in a dry nitrogen-flushed flask, Z-methylpentanoic acid (1242 grams) was added dropwise with stirring. The temperature was maintained at 3545 C. After the addition was completed, the temperature was raised to C. When gas evolution had ceased, the material was fractionated at atmospheric pressure. Z-methylpentanoyl 17 chloride (1176 grams, 82.5 percent) distilled at 137- 139 C.

(B) Preparation of triethylcarbinyl 2-methylpentanoate Materials Mole Moles Quantity weight Ferric nitrate 1 g. Ammonia 2,000 cc. Sodium 22. 997 6. 1 140 g. Triethylcarbinol 116 6 696 g. Z-methylpentanoyl chloride 134.6 6. 13 825 g. Ether 3,000 cc.

Prcedure.To 2000 cc. of liquid ammonia in a dry nitrogen-flushed flask was added 0.5 gram of sodium metal. The blue color was discharged with a stream of dry air; then 1 gram of ferric nitrate was added. The remaining sodium (139.5 grams) was added in small portions with stirring. To this mixture was added a solution of 696 grams of triethylcarbinol in 500 cc. of dry ether. The ammonia was allowed to evaporate overnight, and the reaction mixture was then treated with a stream of nitrogen and heated under reflux for 15 hours, 15 00 cc. of ether being added to the reaction rflask during this time.

Next, a solution of 825 grams of 2-methylpentanoyl chloride in 200 cc. of ether was added dropwise over a 4 h'0ur period. Stirring was continued for 1 hour. Water (l15'00 cc.) was slowly added. The contents of the flask were filtered, and the product was extracted with ether. The ether solution was washed with two 250-cc. portions of 1 0 percent sodium hydroxide and then with water until the wash water was neutral, dried over calcium sulfate, filtered, and freed of solvent at atmospheric pressure. The residue was vacuum fractionated. The product, triethylca-rbinyl 2-methylpentanoate (930 grams; 72.5 percent) distilled at 92-101 C. at Hg.

(0) Preparation of triethylcarbinyl 2-methyl2-ethylpentanoate Pr0cedure.To 2000 cc. of liquid ammonia in a dry nitrogen fiushed flask was added 1.0 gram of sodium. The blue color was discharged with a stream of dry air; then 1.0 gram of ferric nitrate was added. The remaining sodium (99 grams) was added in small portions with stirring. To this mixture, triethylcanbinyl Z-methylpentanoat-e (930 grams) was added dropwise. continued tfior two hours after the addition was completed. Next, a solution of 474 grams of ethyl bromide in 300 cc. of ether was added dropwise. The ammonia was allowed to evaporate, and ether .(1100 cc.) was added to facilitate stirring. Sufficie-nt Water (about 1500 cc.) was added to dissolve the solids formed. The contents of the flask were filtered, and the product was taken up into ether. The ether solution was washed with water until neutral, dried over calcium sulfate, filtered, and freed of solvent at atmospheric pressure. The residue was fractionated. The overhead temperature was taken to 115 C. at 12 mm. Hg. The residue (705 grams) was reduced to the alcohol without further treatment.

Stir-ring was Pr'0cedure.A mixture of grams of lithium aluminum hydride and I1000 cc. of dry ether in a dry nitrogenflushed flask was stirred and heated under reflux 'for 5 hours using a steam bath. Triethylcarbinyl 2-met'hyi-2- ethylpentanoate (705 grams) was added dr-opwise to the reaction mixture. Following the final ester addition, the mixture was refluxed for 16 hours. Water was added very slowly until hydrogen evolution ceased; then 50 percent H SO was added until the solution was acidic. Additional water had to :be added to complete solution of the solids in the flask.

The product was taken up into ether, washed with two 1500-cc. portions of 10 percent sodium hydroxide and with water until neutral, dried over calcium sulfate, filtered, and freed of solvent at atmospheric pressure. The residue was vacuum fractionated. Triethylcanbinol weighing 80.4 grams dis-tilled at 7682 C. at 48 mm. Hg. 2-methyl-2-ethyl-1-pentanol (345 grams; 65 percent) distilled at 80-90" C. at 25 mm. Hg.

Example IX.-Preparation of di-(Z-methyl-Z-ethylpemfyl)2,2,8,8-tetraethylazelate Preparation of 2,2,8,8 tetraethylazelayl chloride Materials Mole Moles Quantity weight 2,2,8,8-tetraethylazelaic acid 300 522 150. 5 g. Thionyl chloride, Eastman grade.-- 118. 98 1. 31 156. 5 g. Benzene, AOS rea ent 200 cc. Pyridine, reagent 2 drops.

Acylation of 2-methyl'2-ethylpentanol with 2,2,8,8-tetraethylazelayl chloride Materials Mole Moles Quantity Weight Ferric nitrate 1 g. Ammonia 1,500 cc. 2methy1-2-ethylpentanol 1 88 245 g. 2 ,2,8,8-tetraethylazelayl chloride 337 94 Ether 2,500 cc. Sodium 22. 997 1. 88 43.2 g.

Pr0cedure.-To 1500 cc. of liquid ammonia in a dry nitrogen-flushed flask was added 0.5 gram of sodium metal. The blue color was discharged with a stream of dry air; then 1 gram of ferric nitrate was added. The remaining sodium (42.7 grams) was added in small portions with stirring over a two-hour period. To the sodium amide mixture a solution of 245 grams of 2-methyl-2- ethylpentanol in 400 cc. of dry ether was added slowly. The ammonia was allowed to evaporate overnight. The mixture was refluxed for eight hours while a stream of nitrogen was passed through it, 500 cc. of dry ether being added to the reaction mixture during this time. Next, the tetraethylazelayl chloride prepared from 0.94 mole of acid was dissolved in 500 cc, of dry ether and added dropwise to the reaction mixture at such a rate as to maintain constant reflux. This was then refluxed for one hour, and water (1500 cc.) was added. The contents of the flask were filtered, and the product was taken up into ether, washed with two 250-cc. portions of 10 percent sodium hydroxide and with water until neutral, dried over calcium sulfate, filtered through Hyflo, and freed of solvent at atmospheric pressure. Volatile materials were removed by heating the mixture to 195 C. (vapor temperature: 88 C.) at 0.5 mm. Hg pressure. The product ester was the residue (436.5 grams; 89 percent).

The residue was refluxed for two hours with 400 cc. of 0.5 N alcoholic potassium hydroxide. The temperature of the reaction mixture was about 78 C. Next, pentane and water were added, and the organic layer was washed with water until neutral, filtered through Hyfio, and reduced to small volume using a water aspirator. The infrared spectrum of the sample showed that it was free of anhydride. Acid number of the product was 0.32. In order to reduce the acid number, the ester was diluted with pentane and percolated through a 12-inch column of basic Amberlite IR-45. The pentane was removed by heating to 120 C. under oil pump vacuum. After filtering through a small inch-thick cake of Hyflo, the ester was still slightly hazy. It was dried over calcium sulfate for several days and filtered again. The product weighed 340 grams and had an acid number of 0.16. After another treatment with IR-45, the acid number was 0.04. Gasliquid partition chromatography indicated that the major component comprised 79.4 percent of the sample.

Example X.Preparation of di-(2,2-dimethylhexyl)2,2, 8,8-zetraethylazelate Materials Mole Moles Quantity weight 2,2-dimethy1hexanol-1 130 4. 62 600 g. Tetraethylazelayl chloride 337 1 0. 75 Ether- 500 cc. Sodium- 22.997 1. 52 35 g.

1 Theory.

Procedure-To 600 grams of refluxing 2,2-dimethylhexanol-l in a dry flask, sodium (35 grams) was added in small portions over a period of 2.5 hours. The mixture was refluxed for one hour, and then a solution of 0.75 mole of crude tetraethylazelayl chloride in 300 cc. of dry ether was added dropwise. The temperature of the reaction mixture remained at 7080 C. during the acid chloride addition without external heating. Refluxing was continued for two hours after the addition. Enough water was added to dissolve the solids formed. The product was taken up in ether, washed twice with 250 cc. of aqueous 10 percent sodium hydroxide and by water until neutral, dried over calcium sulfate, and reduced to small volume at atmospheric pressure. Remaining volatile materials were then removed by heating to 200 C. at 0.5 mm. Hg pressure. Weight of the residue was 378 grams {(96 percent).

Example XI.Preparatin 0f di-(2,2-dimethyl0ctyl)2,2, 8,8-tetraetlzylazelate This product was prepared by the same procedure as used in Example X.

Example XII.Preparati0in of di-(2,2-dimcthyldecyl) 2,2,8,8-tetraethylazelate This product was prepared by the same procedure as used in Example X.

Example XIII .Preparation of di-(2,2-dimethylhexyl) 2,2,6,6-tetramethylpimelate 2,2,6,6-tetramethylpimelic acid was prepared by a pro cedure similar to that used in Example VII.

The ester was prepared by a procedure similar to that used in Example IX.

Example XIV.Preparati0n of 2,8-dimethyl-2,8-dipr0pyl-- azelaic acid (A) Preparation of di-(triethylcarbinyl)2,S-dimethyl-Z,S-dipropylazelate Pr0cedure.$0diun1 amide was prepared from 115 grams of sodium and 2 liters of liquid ammmonia using ferric nitrate as catalyst. Triethylcarbinyl 2-methylpentanoate (1072 grams) was added dropwise, and the mixture was stirred for two hours. A solution of 575 grams of 1,5-dibromopentane and 500 cc. of ether was added dropwise, and stirring was continued for one hour following the addition. Allowing the ammonia to evaporate overnight resulted in loss of part of the reduction mixture through foaming. The mixture was heated for one hour to expel remaining ammonia, and suflicient water was added to dissolve the solids in the flask. The product was taken up into ether, washed with water until neutral, and dried over calcium sulfate. The solution was filtered and freed of solvents by distillation at atmospheric pressure. Distillation at 10 mm. pressure yielded 103 grams at 4095 C. and 106 grams of triethylcarbinyl 2-methylpentanoate at 97101 C. The crude product (residual) weighed 882.5 grams and was hydrolyzed without further purification.

(B) Hydrolysis of di-(triethylcarbinyl)2,S-dimethy1-2,8-dipropylazelate Procedure-To a refluxing solution of 882.5 grams crude di (triethylcarbinyl)2,8 dimethyl 2,8 dipropylazelate in 500 cc. ofdioxane was slowly added concentrated hydrochloric acid (400 cc.). After refluxing two hours, azeotropic distillate was collected which separated into about 700 cc. of an olefinic layer and 280 cc. of dioxane. Additional dioxane (250 cc.) was added to the reaction mixture. The contents of the flask were then poured into two liters of water, and the oily product was allowed to crystallize overnight. The solid was collected on a filter, washed with pentane to remove color, recrystallized from aqueous 10 ethanol-methanol, and washed with pentane. Three crops were obtained. The

Example X V.-Prepamtin 0f di-(2,2-dimethylhexyl) 2,8-dimethyl-2,8-dipropylazelate This product was prepared from 2,2-dimethylhexanol and the acid prepared in Example XIV by a procedure similar to that used in Example IX.

Example X VI .Preparation of 2,8-dimethyl2,8-diethylazelaic acid This material was prepared by a procedure similar to that used in Examples VII and XIV.

Example XVII.Preparati0n of di-(2,2-dimethylhexyl) 2,8-dimethyl-2,8-diethylazelate This product was prepared from 2,2-dimethylhexanol and the acid prepared in Example XVI by a procedure similar to that used in Example 1X.

Example X VIII .-Preparati0n of di-(1H,1H,7H-d0decafluoro-Z -heptyl 2,2,8,8-tetraethylazelate Materials Mole Moles Quantity weight 2,2,8,8-tetraethylazelayl chloride 337 l 1 337 g} Pyridine 79. 1 1. 4 C7 Fluoroalcohol 1. 4 Benzene, AOS reagent 1 Estimated. 2 Theory.

Pr0cedure.--A mixture of 115 grams of pyridine and 100 cc. of benzene was slowly added to a solution of the crude 2,2,8,8-tetraethylazelayl chloride and 1'50 cc. of benzene. After refluxing for one hour, a mixture of 447.5 grams of C7 fluoroalcohol and 100 cc. of benzene was added slowly. The temperature was maintained at approximately 75 C. during the addition. The reaction mixture was then refluxed for three hours. A crystalline material formed in the flask during this time. Sufiicient water was added to dissolve the solids present, and sufficient pentane was added to cause the organic layer to float. The organic layer was washed with dilute hydrochloric acid, water, and 10 percent sodium hydroxide. A large amount of a heavy red liquid settled to the bottom of the separatory funnel with each sodium hydroxide washing. This lower layer, weighing 261 grams, was found to be the fluoroalcohol. When no more fluoroalcohol separated during the sodium hydroxide washing, the organic layer was washed with water until neutral, and dried. An attempt was made to distill the solvents and other volatile materials from the crude ester, but copious acidic fumes were evolved. The crude ester was then filtered through alumina, but acid fumes were evolved again when the product was heated to 195 C. under 0.75 mm. pressure. The infrared spectrum indicated presence of considerable anhydride.

After treating three timess with dilute methanolic potassium hydroxide, the infrared spectrum showed no anhydride. The acid number was 0.67, but it had not proved susceptible of reduction by the base treatment. Gas-liquid partition chromatography furnished an assay of 95.8 percent.

22 Example XIX-Preparation of di-(2,2-rlimethyl0clyl) 3,3-dimethylglufarate This product was prepared from commercially available 2,2-dimethyloctanol and 3,3-dimethy1gultaric acid by a procedure similar to that used in Example IX.

Example XX .Preparation of iii-(2,2-dimethylhcxyl) 3,3,6,6-tetramethylsuberate This product was prepared by the following general procedure:

(1) 3,3-dimethylglutaric anhydride was prepared from 3 ,S-dimethylglutaric acid,

(2) 3,3-dimethylglutaric anyhdride was converted to methyl hydrogen 3,3-dimethylglutarate,

(3) Dimethyl 3,3,6,6-tetramethylsnberate was prepared from methyl hydrogen 3,3-dimethylglutarate,

(4) Dimethyl 3,3,6,6-tetramethylsuberate was transesterified with 2,2-dimethylhexanol to form di-(2,2-dimethylhexyl) 3 ,3 ,6,6-tetramethylsuberate.

Example XXl.-Preparation 0 2-methyl-2-ethyl-1,3- propanediol di-(2,2-dietlzylpentan0rzte) (A) Preparation of 2,2-diethylpentanoie acid 2,2-diethylpentanol was converted to 2,2-diethylpentanoie acid according to the procedure of J. Kenyon and B. C. Platt (J. Chem. Soc., 633, 1939). Yields of 53 and 48 percent were obtained. A typical preparation was as follows:

Materials Mole Moles Quantity,

weight g.

2,2-diethylpentanol-1 144 1 144 NaOH analytical reagent 40 0.75 30 KMnO analytical reagent 158 2 15 340 S0 commercial Pr0cedure.-Potassium permanganate (340 grams) in 3000 cc. of water was added slowly to a well-stirred mixture of 144 grams 2,2-diethylpentano1 and 30 grams sodium hydroxide dissolved in 250 cc. of water. After twelve hours, the heat of reaction had dissipated. The mixture was then heated to C. for one hour. Gaseous sulfur dioxide was introduced into the solution until it was acidic and the manganese dioxide went into solution. The organic layer formed was taken up in ether, washed well with water, and dried over Drierite. The filtered solution yielded 84 grams of 2,2-diethylpentanoic acid, distilling at 133137 C. at 17 mm. Hg pressure. The yield was 53 percent, based on alcohol. Acid number: calculated, 354; observed, 348.

(B) Preparation of 2,2-diethylpentanoyl chloride Materials Mole Moles Quantity weight 2,2-diethylpentanoic acid 1.08 g. Thionyl chloride, practical 2 238 g. Pyridine, purified 2 2 drops.

- Analysts 77 1952 pages 915932, or

1 ma d 1 t1 2,241 tl 1- (O) Acylatlon or z-mettllgilazlgyllsghlorirglreopane 10 W1 1 w W Petroleum Refiner, November 1955, pages 165-169.

4 1 H In addition to the data shown, infrared spectra were Mammals gfi MO es Quan 1 y determined on the various esters.

5 TESTING PROCEDURES (EXAMPLES VIIXXVII 1"6 0. 98 172 glggtlgilggl-lgarllseg,ggggiiffidiol 118 gg i Thermal stability m'glass (copper present) 1 'd' if yn me pm A ZO-gram sample of the ester is placed 1n a tube 60 10 cm. long and 2.5 cm. in diameter and fitted with a side arm 8 cm. from the top of the tube to which is Prsolcfizz/ 25332;}lgtllilfiiglriaf gygocghglr1Z lg attached througga sttlandard tfapehr joint at [lg-tube Colfjlild was 0 t t t t u 50 grams of 2-methY1-2-ethY1-1firropanedml- The r fnci ti iger jo int io hi eh is fit t e d a s top co ck with action mixture was externally heated during the addition, an 8 mm tube extending inside the test tube to and sol d began forming at 88 C. It was then heated within 10 cm. of the bottom. The stopcock is opened,

a a 1 t 't' t se was added. and the product w taken up ether, washes ilfminfiifi ifafiiiillid healed 30 663 13331 48 2.52 with hydrochloylq a hil d llfh g 5;? The weight loss due to volatility, the percent viscosity neutral dned Over F q dlstl g1 h 1 6 change, and the acid number increase are noted. Per- 2 Y 1,3 d1 let yopcntanoa centage decomposition is calculated from the acid numwelghlggh 9-1 d gg dlstlne: 3 2 ber increase, using the theoretical saponification num- 6 X Was Parcen F on a c her as representative of 100 percent decomposition. The liquid partition chromatography indicated that the ester 25 test was Conducted in the presence of a 1 by 6 cm coppgr was Percent homogeneous' strip. The weight change of the copper is determined.

Example XXII .Preparation of 2-methyl-2-cthyl-L3- Th l stability i steel propanedmldl'lcdezhybz'lsopmpylhexanoate) A 20-m1. sample of the ester is placed in a cylinder 7 Thi d t was prepared b th f ll i general inches long made from three-quarter-inch stainless Steel procedure: tubing. A gauge is attached for pressure reading. The bomb is sealed under one atmosphere of nitro en and y f j y chlorldi Was Prepared from immersed in an aluminum block bath for 6 hours at 600 exarlolc aCl F. (316 C.). The gauge pressure durin the test'and f i iifii iii fio fifiifi ?ififi iieahii$555 -Z fli Pemnmg; Yiscgsitt chzmge i? the aci num er lncrease are 0 tame ercentage ecom: Tflethylcafblnyl 1 1 P PY Was position is calculated from the acid number increase using p p l 1fromfltrleflflylcafblllyl z'ethylheXanofite and the theoretical saponification number as representative of P PY foml 100 percent decomposition. (4) Triethylcarbinyl 2-ethyl-2-isopropylhexanoate was 40 H d I I hydrolyzed to form 2-ethyl-2-isopropyl hexanoic acid, ync Stabhty (5) 2-ethyl-2-1sopropyl h xan lC 3 11 was Converted to Hydrolytic stability was determined by means of saponthe chlonde h 1 1 h ification number. The saponification number obtained (6) Y was my med Wlt 0n the sample was compared to the theoretical saponificae-ethyl-2-1sopropylhexanoyl chloride to form the tion numben Product The procedure used a 2 hour reflux of the ester sample In the examples the expression GLPC refers to gas i g ASTM procedure BT94 was liquid partition chromatography. This analytical techp y Physical tests nique is adequately described in either of the following publications:

The various physical tests employed ASTM procedures.

TABLE V.II'IYSICAL PROPERTIES OF ESTERS IN EXAMPLES VII-XXII Pour Kinematic viscosity (cs.) Flash Ester polnt, ASTM point,

F. slope F.

-40 F. 100 F. 210 F.

Di- (2-methyl-Zethylpeutyl) 2,2,8,8-tetraethylazelate -20 144. 3 9. 50 0. 847 465 Di-(2,2-dimethylhexyl)2,2,8,8-tetraetl1ylaz late -25 106. 1 8. 47 0.830 450 Di- (2,2-dimethyl0ctyl) 2,2,8,8-tetraethylazelate -40 93. 91 8.82 0. 776 460 Di-(2,2-dimethyldecyl)2,2,8,8-tetraethy1azelate -45 112. 7 10. 51 0. 742 495 Di-(2,2-dimethylhexyl)2,2,6,6-tetramethylpimelate 44, 822 20. 56 3.71 0.813 380 Di-(1H,1H,7H-dodecafluor0-1-heptyl)2,2,8,8-

tetraethylazelate -20 105. 47 7. 27 0. 900 Di (2,2dimethyloetyl)3,3-dimethylg1utarate -05 13, 282 20. 83 3. 93 0. 775 Di-(2,2-dimethylhexyl)3,3,6,6-tetramethylsuberate 30, 000 41.13 5. 55 0. 790 Di-(2,2-dimethylhexy1)2,8-dirnothyl-2 8-Clipropylazelatc -40 69. G4 6. 67 0. 842 2methyl-2-ethyl-1,3-propanodi0l di-(2-2,di-

ethylpentanoate) -40 32. 98 4. 43 852 Z-methyl-Z-ethyl-l,3-propanediol di-(2ethy1-2- isopropylhexanoato) -40 109. 4 7. 97 862 1 Data not obtained.

TABLE IX.-DATA ON THERMAL STABILITY IN STEEL PRESSURE CYLINDER ESTERS OF EXAMPLES VII-XXII Viscosity at 100 F. (03.)

Acid num- Percent Ester ber increase decomposi- Original Final Percent tion 2 change Di- 2 Z-dimeth lhex l 2 2 8 S-tetraeth laze- Di-(2,2-dimethylhexyl)3,3,6,6-tetrarnethyl suberate 41. 13 40. 85 0. 7 1. 3 0. 5 Di-(2,2-dimethyloctyl)3,3-dimethylglutarate. 20. 83 19. 51 6. 3 2. 1 0.8 Di-(1H,1H,7H-dodecafluor0-1-heptyl)2,2,8,8-

tetraethylazelate 105. 45 93. 27 11. 6 2. 8 2. 4 Di-(isooctyl) azelate 12. 58 10. 94 -13. 0 32.4 11.9 EDi-(2-ethylhexyl) sebacate 12. 59 11.63 -7. 6 30. 2 11.5 Di-(2,2-diethylpenty1) azelat 25. 32 11.96 --52. 8 58. 1 22. 8 2-methyl-2-ethyl-1,3-propane ethylpentanoate) 32. 98 31. 91 -3. 2 5. 4 1. 9

1 A -ml. sample is maintained at 600 F. (316 C.) for six hours under nitrogen. 2 Percentage decomposition=100 (acid number increase)/(theoret1cal saponificatlon number).

TABLE X.PHYSICAL PROPERTIESESTE RS OF EXAMPLES XXIII-XXVII Viscosity in centistokes ASTVI Poutr Fliasli 1 pom p0 n slope F. F. 40 F. 100 F. 210 F.

2,2-dimethylvalerates:

2-ethyl-2-loutyl-1,3-propanediol 10, 610 13. 41 2. 87 0. 82 65 330 2,2,5,5-tetramethyl-1,G-hexanediol 20,280 17.72 3. 48 0.80 70 345 2-methyl-2-ethylhexanoates:

2-methyl-2-propyl-1,3-propanediol 23. 88 3. 67 0. 87 60 375 2,2,5,5-tetramethyl-1,fi-hexanediol 46. 15 5. 22 0. 86 -60 380 2-2-dimethyltetradecylate: 2-methyl-2-propyl- 1,3-pr0panediol 10,616 36.82 6.35 0. 69 -55 485 1 Viscosity at F.

TABLE XI-THERMAL AND HYDROLYTIC STABILITY from the dro in funnel at a rate which maintained en- DATA ESTERS OF EXAMPLES XXIII-XXVII fie reflux (gopfilingutes) g 2 2 th 1 mates The reaction was refluxed for 30 minutes, and then 1 lme y Va liter of tetrahydrofuran was distilled from the flask with stirring. The flask was cooled with an ice bath; then -2- 2, t ilgrfi fil gfifi i ifig ifi 40 300 ml. of H 0 were added, very carefully at first, foldiol lowed by 150 ml. of concentrated sulfuric acid in 1 liter of water and finally by 600 ml. of ether. $5- M6 In a separatory funnel, the water phase was drawn oif Percent chang 1 vis and discarded. The ether phase was extracted with 250 ggg g gggg -g -i; ml. of 10 percent sodium bicarbonate. Acidification of Hydrolytic stabilit the bicarbonate extract gave 31.5 grams of unreacted acid. 15 minutes:

saponificafion NO 20.9 2M This was lmmedlately reduced by the procedure ust Iercent saponification 7. 2 7. l e I 30 gggfgh No 39 0 96 0 The ether solutions from both reductions were com- Percent saponification 1314 9:3 bined, dried with sodium sulfate and calcium chloride,

Example XXIII.Preparati0n 0f 2-ethyl-2-butyl-1 ,3- propanediol ester of 2,2-dimethylvaleric acid The preparation of the acid employed a procedure similar to that used in Example VII, with the exception that a monobromide, instead of a dibromide, was used.

The glycol used was commercially available.

The esterification procedure was similar to that used in Example IX.

Example XXIV.Preparati0n of 2,2,5,5-letmmethyl-I,6-

hexanediol ester of 2,2-dimethylvaleric acid dropping funnel, and reflux condenser with drying tube,

36 grams (0.95 mole, metal hydrides) of lithium aluminum hydride were slurried in 600 ml. of dry tetrahydrofuran. While the slurry was rapidly stirred, 126.2

grams (0.625 mole) a,a,a',a'-tetramethyladipic acid dissolved in 1,150 ml. of dry tetrahydrofuran were added and stripped of ether. The product, a tan solid, was distilled in a Koelsch flask at 0.5 mm. The yield of white, waxy material, M.P. 7679 C., was 76.8 grams (0.441 mole, 71 percent).

No carbon-hydrogen analysis was made of this new diol itself, but the composition of its pivalate ester was determined and found to check with the theoretical value.

The ethyl ester of a,a,a',a-tetramethyladipic acid was also made and reduced to the diol.. A solution of 35 grams (0.173 mole) of the crude acid, 300 ml. of absolute ethanol, and 5 ml. of concentrated sulfuric acid was refluxed for 14 hours and poured into a separatory funnel with ether and water. After extraction with 10 percent NaI-ICO and drying, the ether solution was stripped of ether. Distillation through a short Vigreux column gave 28.5 grams (0.111 mole, 64 percent) of colorless liquid, B.P. 92-94" at 2 mm.

Using a 1-liter, 3-necked flask equipped with Trubore stirrer, reflux condenser, and dropping funnel, 28.5 grams (0.111 mole) of the ester were added at reflux rate to a slurry of 4.5 grams (0.119 mole, metal hydrides) of lithium aluminum hydride in ml. of ether. The mixture was refluxed for 30 minutes after the addition. About 40 ml. of H 0 were added carefully to the cooled flask, followed by 22 ml. of concentrated sulfuric acid in 200 29 ml. of H 0. The resulting ether solution of product was worked up just as in the acid reduction. The yield of diol (undistilled) was 17.6 grams (0.101 mole, 91 percent).

The esterification procedure was similar to that used in Example IX.

Example XXV-Preparation f 2-methyl-2-pr0pyl-L3- propanediol ester of Z-methyl-Z-ethylhexanoic acid The preparation of the acid employed a procedure similar to that used in Example VII, with the exception that a monobromide, instead of a dibromide, was used.

The glycol used was commercially available.

The esterification procedure was similar to that used in Example IX.

Example XX VI.Preparati0n of 2,2,5,5-tetrwmethyl-l,6- hexanediol ester 0 2-methyl-2-ethylhexan0ic acid The preparation of the acid employed a procedure simi lar to that used in Example VII, with the exception that a monobromide, instead of a dibromide, was used.

The preparation of the glycol is described in Example XXIV.

The esterification procedure was similar to that used in Example IX.

Example XXVlI.-Preparati0n of 2-methyl-2-pr0pyl-1,3- propanediol ester of 2,2-dimethyltetradecanoic acid The preparation of the acid employed a procedure similar to that used in Example VII, with the exception that a monobromide, instead of a dibromide, Was used.

The glycol used was commercially available.

The esterification procedure was similar to that used in Example IX.

While particular embodiments of the invention have been described, it will be understood, of course, that the RH O R:

where R is an acyclic alkyl group of from 1 to 4 carbon atoms, R is an acyclic alkyl group of from 1 to 10 carbon atoms, R is an acyclic alkyl group of from 1 'to 4 carbon atoms and n is an integer of from 1 to 9.

2. The chemical compound di-(2,2-dimethylhexyl)-3,3, 6,6-tetramethylsuberate.

References Cited by the Examiner UNITED STATES PATENTS 8/58 Airs et al. 260485 9/58 Henne et al. 260485 6/59 Blake et al. 260-485 8/62 Emrick 260--410.6

OTHER REFERENCES Asano et al.: Chemical Abstracts, vol. 45, p. 56170 (1951).

Birch et al.: Chemical Abstracts, vol. 47, p. 1031d (1953).

LORRAINE A. WEINBERGER, Primary Examiner.

Claims (1)

1. CHEMICAL COMPOUNDS HAVING THE FORMULA