US2923719A - Preparation of condensation products of acid anhydrides - Google Patents

Description

PREPARATION OF CONDENSATION PRODUCTS OF ACID ANHYDRIDES Johannes Donatus von Mikusch-Buchberg and Karlheinz Hermann Mebes, Hamburg-Harburg, Germany, assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Application October 1, 1956 Serial No. 612,940

Claims priority, application Great Britain October 7, 1955 9 Claims. 01. 26(l343.5)

. described a process for obtaining condensation products from fatty acids. It has now been found that useful condensation products may be obtained by heating fatty acid anhydrides, particularly anhydrides of unsaturated fatty acids, at temperatures between 180 and 300 C., provided that the water formed during the reaction is removed.

The present invention provides therefore a process for WQQ.

2 Fatty acids for use according to the invention have the formula R.COOH

where Rhas the same meaning as above. Suitable fatty acids are linoleic acid, linolenic acid, or the highly unsaturated acids occurring in marine oils, such as herring oil, whale oil, pilchardoil, and sardine oil.

Fatty ketones" for use according to the invention have the formula R.CO.R'

where .R and R have the same meaning as above and may be the same or different.

Fatty acid anhydrides, fatty acids, or fatty ketones which contain only one double bond may be used in starting materials for the preparation of condensation products according to the invention but it is preferred to use at least a proportion of fattycompounds containing unsaturated alkyl groups with two or more double bonds.

The starting material may contain a minor proportion of other constituents such as, for example, fatty oils, mono-, dior triglycerides or resin acids. These constituents have a tendency to slow down the desired reaction andhence too great a proportion should be avoided.

The temperature and time of heating employed and the proportion of unsaponifiable matter which can be obtained depend to somedegree on the types of fattyan- I hydrides, ,acids and ketones which are used as starting thepreparation of condensation products which comprises heating a non-hydroxylated fatty acid anhydride between 180 and"300 C. with removal of the water'formed in the reaction until'the product contains a substantial proportion of unsaponifiable matter having a mean molecular weight in accordance with that calculated for a. condensation product of at least 3 molecules. of the fatty acid corresponding to the fatty acidanhydride.

The starting material may also contain fatty acidsin admixture with the fatty acid anhydride. The fatty acids maybe the same or different fatty acids as those from which the fatty acid anhydrides are derived. The. starting material may further contain fatty .ketones which may be derived from the same or different fatty acids as those from which the fatty acid anhydrides are derived. Fatty acid anhydrides for use according to the invention should have the formula where R and R are hydrocarbon groups, preferably long saturated or unsaturated hydrocarbon chains, which are preferably unsubstituted. The hydrocarbon chain must not contain hydroxyl groups. .It is preferred that R and R are unsaturated alkyl groups having a chain length of from.9 to'25 carbon atoms, the most preferred chain length being from 17 to 21 carbon atoms. Thus, fatty anhydrides containing from 20 to 52 carbon atoms are preferred, most preferably from 36 to .44 carbon atoms. R.and:R .are preferably identical,.but may bedifferent.

..;Examples of suitable fatty acid anhydrides are the fatty acid anhydrides derived from groundnut oil andthe anhydrides derivedfrom the treatment of linseed oilfatty acids with acetic anhydride.

- materials.

Thus, with fatty compounds which have a relatively low iodine value, heating can be carried out at highternperatures for a long time and high proportions of unsaponifiable matter, for example 70% to nearly can be obtained. With' fatty compounds of high iodine, value, for example over 150, heatingmay have to be discontinued earlier, since gelation may take place and the proportion of unsaponifiable matter may then be lower, for example 40 to 60%.

According to the purposes for which it is desired to use the condensation products of the invention the degree ofconversion of the free fatty anhydrides to unsaponifiable matter having the characteristics specified may vary within wide limits. For certain purposes, a degree of conversion of from 20 30%' .may'be suflicient, whilst for other purposes a degree of conversion of from 3040% may be sufficient. It is preferred that the degree of conversion should be at least 40%.

I The fatty compounds used as starting materials may, in some cases, be purified with advantage according to the usualmethods.

It is preferred to have a catalyst present, particularly if substantial amounts of fatty acids or fatty ketones are present. The catalyst used in the processes of the invention may be a boron compound. It is preferred to use oxygen-containing boron compounds. Preferred inorganic boron compounds are boric acid and its derivatives and boric oxide. Boron salts such as, for example, the .alkali pentaborates, preferably ammonium pentaborate, may also be used with advantage. Borax has only slight activity as a catalyst, however. Boron compounds with oxidizing properties may be undesirable.

Preferred organic boron compounds are the esters of boric acid, such as boric acid t-rimethyl ester, boric acid triethyl ester, and boric acid mannitol ester, the mixed anhydride of boric acid and acetic acid or the mixed anhydride of boric acid and higher fatty acids such as are obtained, for example, from groundnut oil.

The catalyst may be supported on a suitable carrier, for example an oxide of silicon such as kieselguhr, diatomite or silica gel. When a supported catalyst is used the catalyst may be dissolved or suspended in water and the carrier material added, the resultant mixture being dried in an oven.

The amount of catalyst may vary widely, for example, between 0.1% and by weight of the starting material. Generally, 0.1% to 2% is sufficient when mixtures containing a large proportion of fatty acid anhydride are used as starting materials. The catalyst may be mixed with the starting material or added during the heating in the reaction vessel, or it can be placed in the reflux column.

The mixture in the vessel is heated to temperatures between 180 and 300 C. It is desirable to keep the reaction mixture at temperatures between 240 and 300 C. for at least the latter part of the time during which the reaction is effected, especially if it is desired to obtain a product with superior drying properties. The reaction may be carried out at atmospheric pressure, for example under an inert gas such as carbon dioxide, but preferably under vacuum.

Heating is preferably carried out in such a manner that refluxing of the higher boiling compounds occurs.

The reflux column may be packed, for example, with helices, Raschig rings or the like. The reflux column may also be regulated in such a way that part of the fatty acids are allowed to distil off.

After heating, any unchanged fatty compounds in the reaction mixture may be dissolved out by a suitable solvent, for example, alcohol. Alternatively, the reaction mixture may be distilled, if desired, under vacuum, to remove unchanged fatty materials. The residue after solvent treatment or distillation is the desired product. Preferably the reaction mixture is filtered, washed with hot water to remove the catalyst and dried under vacuum before solvent treatment or distillation.

The distillate or solvent extract may be reused for a further reaction since it consists substantially of unchanged starting material. If thereaction is allowed to proceed to a stage where only a small proportion of unchanged starting material is contained in the reaction mixture there may be no need to remove the unchanged starting material.

The residue, obtained as described above. forms the main product. When the starting material contains unsaturated fatty anhydrides the product shows better drying properties than the corresponding triglycerides and decreased volatility and increased viscosity when compared with the fatty anhydrides forming the starting material. The changes in these properties become more evident with increased time or temperature of heating. The analytical figures show the formation of a substantial proportion of unsaponifiable matter which is different from known fatty ketones. This unsaponifiable matter is mainly responsible for the good drying properties and when isolated shows outstanding film forming properties.

The invention also includes the novel condensation products obtained by these processes as such, or in admixture with unchanged fatty anhydrides and acids.

The condensation products of the invention are characterised by a substantial amount, preferably at least 40%, of unsaponifiable matter, a low acid and saponification value, an increased iodine value, according to Wijs, as compared to the starting material and a high mean molecular weight. The mean molecular weight of the unsaponifiable matter is roughly in accordance with, or higher than, the calculated molecular weight of a theoretical condensation product of three molecules of fatty acid. The condensation product has drying properties when the iodine value (determined according to Wijs method) is 100 or higher. Condensation products containing from 20 to 30% of unsaponifiable matter have been found useful for certain purposes whilst for other purposes condensation products containing from 30 to 40% of unsaponifiable matter are valuable.

The condensation products have a molecular structure which contains at least three alkyl chains. The preferred products are those in which the alkyl chains are those of unsaturated acids derived from fatty oils, or are shorter than the chains of unsaturated acids derived from fatty oils by the loss of one carbon atom in the condensation reaction.

The invention also includes the use of the above mentioned products having an iodine value (determined by Wijs method) of 100'or higher, to replace drying materials, such as drying oils, oleo resinous varnishes, or alkyd resins in the paint, varnish, linoleum and allied industries.

The new products may be mixed with the usual siccati ves based on cobalt, lead or manganese and may be diluted with turpentine, mineral spirits or othervolatile solvents to the desired viscosity.

Zinc white enamels prepared from the condensation products showed no signs of livering.

The invention will now be illustrated by the following examples. In the examples the temperatures quoted are those of the metal bath surrounding the reaction vessel, except when otherwise indicated. The temperature within the reaction mixture was lower, by about 20 and C. during the initial stages and by about 10 C. during the final stages of the reaction.

Example 1 100 grams of groundnut fatty acid anhydride (acid value 101.3; saponification value 199.8; iodine value 101.4; unsaponifiable matter 4%) and 2 grams of finely pulverized boric acid anhydride were heated over 3 hours up to a temperature of 290 C. in an evacuated flask fitted with a reflux cooler. After the heating had been continued at this temperature for 4% hours under reflux conditions the reflux conduit was disconnected and the heating was continued for a further /2 hour at the same temperature whilst the distillate was collected in a receiver. Throughout the experiment the apparatuswas evacuated to about 3 mms. mercury pressure. The treatment gave the following materials:

Grams Residue (inclusive of catalyst) 83.04 Distillate 6.25 Fatty matter in the conduits 3.35 Water 6.46 Carbon dioxide 2.70 Loss 0.20

The residue was found to possess very good film-building properties and, after the solid catalyst had been filtered off and 0.3% lead and 0.02% manganese had been added as naphthenates, became dry to the touch in 8 hours and practically non-tacky in 17 hours. Analysis of the residue gave an acid value of 4.9, a saponification value of 26.9, an iodine value of 115.4 and 96.4%- of unsaponifiable matter. The distillate consisted of fatty acids and had an acid value of 133.7, a saponifi cation value of 209.3 and an iodine value of 92.4.

Example 2 66 grams of groundnut fatty acid anhydride and 34 grams of linseed oil fatty acid were heated with 2 grams of boric acid over 3 hours up to 290 C. and the mixture was heated for 4 hours at 290 C. undera vacuum of 3 mm. mercury under reflux conditions. The reflux conduit was disconnected for the last 10 minutes of the heating so that the distillate collected in a receiver. The residue, weighing 77.5 grams without catalyst, was gelatinous, but when boiled with water became a viscous liquid once more. It had an acid value of 9.6, a saponification value of 43.9, an iodine value of 154.0 and contained 92.6% of unsaponifiable matter. The viscous liquid product was diluted with half its weight of a solvent consisting of 1 part of turpentine to 1 part of mineral spirits and siccativated with lead/manganese naphthenate. The resultant material dried as a thin film in 2% hours.

Example 3 38.4 grams of groundnut fatty acid ketone obtained from groundnut fatty acids with an iodine value of 96.8 and 41.6 grams of groundnut fatty acid anhydride, obtained from the same groundnut fatty acids by boiling with acetic acid anhydride in the presence of a little phosphoric acid, were heated with 1.6 grams boric acid over 3 hours up to 290 C. in an evacuated reflux apparatus and were then heated at 290 C. for a further 5 hours. During the last half hour the reflux conduit was disconnected and the condensate was collected in the receiver. The residue was 66.9 grams after removing the boric acid and had an acid value of 8.0, a saponification value of 21.8, an iodine value of 155.6. When siccativated the product was dry to the touch in 5 days and completely dry in about 7 days.

We claim:

1. A process for preparing condensation products, which comprises heating an anhydride of the formula R.C0.0.CO.R' where R and R each consists of an unsubstituted long chain hydrocarbon radical, at a temperature of 180 to 300 C., in the presence of a catalyst selected from the group consisting of boric acid, boric oxide, ammonium pentaborate, trimethyl borate, triethyl borate, m-annitol borate and the mixed anhydrides of boric acid and fatty acid, until the reaction mixture contains at least 40% by weight of unsaponifiable matter derived from the anhydride and of mean molecular weight at least three times that of an acid of which the anhydride is a derivative, the heating being carried out under such conditions that water liberated during the reaction is removed from the reaction zone as it is formed but the loss of the major part of the anhydride is avoided.

2. A process for preparing condensation products, which comprises heating an anhydride of the formula R.C0.0.CO.R where R and R each consists of an unsubstituted long chain hydrocarbon radical, at a temperature of 180 to 300 C., in the presence of a catalyst selected from the group consisting of boric acid, boric oxide, ammonium pentaborate, trimethyl borate, triethyl borate, mannitol borate and the mixed anhydrides of boric acid and fatty acid, until the reaction mixture contains at least 40% by weight of unsaponifi-able matter derived from the anhydride and of mean molecular weight at least three times that of an acid of which the anhydride is a derivative, the heating being carried out under such conditions that water liberated during the reaction is removed from the reaction zone as it is formed but the loss of the major part of the anhydride is avoided, and the reaction mixture being kept at 240 to 300 C. at least during the latter part of the reaction.

3. A process according to claim 2 wherein any sub- 6 stantial amounts of uncondensed fatty material are ultimately removed.

4. A process according to claim 1 wherein the treated anhydride contains from 20 to 52 carbon atoms.

5. A process according to claim 1 wherein the treated anhydride contains from 36 to 44 carbon atoms.

6. A process according to claim 2 wherein R and R are identical unsaturated hydrocarbon radicals containing from 9 to 25 carbon atoms in chain formtaion.

7. A process according to claim 2 wherein R and R are identical unsaturated hydrocarbon radicals containing 17 to 21 carbon atoms in chain formation.

8. A process for preparing condensation products, which comprises heating an anhydride of the formula R.C0.0.CO.R where R and R each consists of an unsubstituted long chain hydrocarbon radical, at a temperature of to 300 C., in the presence of a boric acid catalyst, until the reaction mixture contains at least 40% by weight of unsaponifiable matter derived from the anhydride and of mean molecular weight at least three times that of an acid of which the anhydride is a derivative, the heating being carried out under such conditions that Water liberated during the reaction is removed from the reaction zone as it is formed but the loss of the major part of the anhydride is avoided.

9. A process for preparing condensation products, which comprises heating an anhydride of the formula R.C0.0.CO.R where R and R each consists of an unsubstituted long chain hydrocarbon radical, at a temperature of 180 to 300 C., in the presence of a boric oxide catalyst, until the reaction mixture contains at least 40% by weight of unsaponifiable matter derived from the anhydride and of mean molecular weight at least three times that of an acid of which the anhydride is a derivative, the heating being carried out under such conditions that water liberated during the reaction is removed from the reaction zone as it is formed but the loss of the major part of the anhydride is avoided.

References Cited in the file of this patent UNITED STATES PATENTS 1,987,559 Hintermaier Jan. 8, 1935 2,251,550 Lieber Aug. 5, 1941 2,411,567 Fisher Nov. 26, 1946 2,465,073 Dombrow et al Mar. 22, 1949 2,465,337 Miller et al Mar. 29, 1949 2,513,825 Sorensen July 4, 1950 2,544,365 Sorensen Mar. 6, 1951 2,730,530 Ohlson et-al Jan. 10, 1956 OTHER REFERENCES Man et al.: J. Am. Chem. Soc., vol. 72, pp. 3294-5 (1950).

Claims (1)

1. A PROCESS FOR PREPARING CONDENSATION PRODUCTS, WHICH COMPRISES HEATING AN ANHYDRIDE OF THE FORMULA R.CO.O.CO.R'' WHERE R AND R'' EACH CONSISTS OF AN UNSUBSTITUTED LONG CHAIN HYDROCARBON RADICAL, AT A TEMPERATURE OF 180 TO 300*C., IN THE PRESENCE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF BORIC ACID, BORIC OXIDE, AMMONIUM PENTABORATE, TRIMETHYL BORATE, TRIETHYL BORATE, MANNITOL BORATE AND THE MIXED ANHYDRIDES OF BORIC ACID AND FATTY ACID, UNTIL THE REACTION MIXTURE CONTAINS AT LEAST 40% BY WEIGHT OF UNSAPONIFIABLE MATTER DERIVED FROM THE ANHYDRIDE AND OF MEAN MOLECULAR WEIGHT AT LEAST THREE TIMES THAT OF AN ACID OF WHICH THE ANHYDRIDE IS A DERIVATIVE, THE HEATING BEING CARRIED OUT UNDER SUCH CONDITIONS THAT WATER LIBERATED DURING THE REACTION IS REMOVED FROM THE REACTION ZONE AS IT IS FORMED BUT THE LOSS OF THE MAJOR PART OF THE ANHYDRIDE IS AVOIDED.