US2459116A - Mineral oil composition - Google Patents

Description

Patented Jan. 11, 1949 MINERAL OIL COMPOSITION Edward Oberright, Woodbury, N; J., assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application July 6, 1945, Serial No. 603,594

8 Claims. (Cl. 252-4237) This invention has to do in a general way with mineral oil compositions and is more particularly related to compositions comprised of mineral oil and a minor proportion of an addedingredient which will improve the oil in one or more important respects. a

It is well known to those familiar with the art that mineral oil fractions refined for their various uses are in and of themselves usually deficient in one or more respects so that their pracfor which they have been refined. For example,

mineral oil fractions refined for use as lubricants have a tendency to oxidize under conditions of use, with the formation of sludge or acidic oxidation products; also, the lighter fractions such as gasoline and kerosene tend to oxidize with the formation of color bodies, gum, etc. In order to prevent the formation of these products and thereby extend the useful life of the oil fraction, it is common practice to blend with such oil fraction an additive ingredient which will inhibit'oxidation, such ingredients being known to the trade as oxidation inhibitors, antioxidants, sludge inhibitors, gum inhibitors, etc.

It is also the practice to add other ingredients to mineral oil fractions for the purpose of improving oiliness characteristics and the wear-reducing action of such mineral oils when they are used as lubricants, particularly when the oils are used for the purpose of lubricating metal surfaces which are engaged under extremely high pressures and at high rubbing speeds.

Various other ingredients have been developed for the purpose of depressing the pour point of mineral oil fractions which have been refined for use as lubricants. Most refining treatments provide oils containing a small amount of wax which, without the added ingredient, would tend to crystallize at temperatures which render the oil impracticable for use under low temperature conditions. Additive agents have also been developed for improving the viscosity index of lubricating oil fractions. In the case of internal combustion engines, particularly those operating with high cylinder pressures, there is a decided tend,- ency for the ordinary lubricating oil fractions to form carbonaceous deposits which cause the piston rings to become stuck in their slots and which fillthe slots in the oil ring or rings, thus materially reducing the efficiency of the engine. Ingredients have been developed which, when added to the oil, will reduce this natural tendency of the oil to form deposits which interfere with the function of the piston rings.

It has also been discoveredthat certain types of recently-developed hard metal alloys, such as cadmium-silver alloy bearings, are attacked by ingredients in certain' types of oils, particularly oils of high-viscosity index obtained by various methods of 1 solvent refining. This corrosive action on such alloyshas led to the development of corrosion inhibitors which may be used in solvent-refined oils to protect such bearing meta against this corrosive'action: v 7 g In the lighter mineral oil fractions, such-as those used for fuel purposes, particularly in internal combustion engines, it has been found that the combustion characteristics of the fuel may be controlled and improved by-adding minor-proportions" of various improving agents thereto.

' The'various ingredients which have been developed for use in mineral oil fractions to improve such fractions in the several characteristics enue merated above are largely specific'to their. particularapplications. Therefore, it has been the practice to add a separate ingredient for each of the improvements which is to be effecte,d.,,

The. present invention is predicated upon the discoveryof; a group or class of, oil-soluble reaction, products, or compounds which, when added to mineral oil fractions'in minor proportions, will improve the oil fractions in several respects.

The novel addition agents contemplated by this invention as multi-functional improvers for mineral oils are oil-soluble, sulfur-containing reaction products obtained by reacting elementary sulfur or asulfur halide, or a mixture thereof, with a condensation product of an aldehyde, a heterocyclic amine and a hydroxyaromatic compound (and metal salts thereof), the condensation products and their corresponding metal salts being represented by the general formula:

out n l J j R i|i- (II-Y wherein A is an aromatic nucleus, either monoor poly-cyclicyR' is either hydrogen or an alkyl, aralkyl, alkaryl, aryl, cycloalkyl, alkoxy or aroxy group; a represents the number of R groups atat a secondary (heterocyclio) nitrogen atom to the carbon atom of a l I ia group; and c represents the number' of groups attached to an aromatic nucleus A and is an integer from 1 to 3. It will be cleanthatwhem A is a phenyl nucleus, the sum of a, b and 0 will not exceed 5; and when A is a naphthalene nucleus or other poly-cyclic nucleus; thesumimaygf" exceed 5.

Aldehydes contemplated by the present invena tion are the aliphatic aldehydes, typified by formaldehyde (such as'trioxymethylene), ,acetfurfu-ral; etc.

and the like; in short, any substituent which does not take a major part in the reaction; Pref.- erence, however, is given to the aliphatic aldehydes, formaldehyde being particularlypreierred, i

The secondary heterocyclic amines are those characterized by attachmentpf a hydrogen atomto a nitrogenatom 'in the; heterocyciicz; roup.

Representative of the amines contemplated herein are morpholine, thiomorpholine, pyrrole, pyrro" indole, pyrazole, pyrazoline;

line, .pyrrolidine, pryazolidine, piperidine, phenoxazine; phenthiazinc and their C-substituted analogs. Substituent groups, attached to the carbon "atoms. of'these,

amines are typified by alky, aryl, alkaryl, iaralkyl, cycloalkyl, etc. Preferred of th'eseaminess'is morpholine. e l r Representative hydroxyarom'atici compounds contemplated by the present invention.. are phenol, resorcinal, hydroquin'one; catechol cresol, xylenol, hydroxydiph'enyl, benzylphenol, phenylethylphenol, phenol resins, methylhydroxydi phenyl, guiacol, alpha 'and'beta-naphthol, alpha and beta methylnaphthol, tolylnaphthol,xylylnaphthol, benzylnaph-thol, anthranol, phenylmethylnaphthol, phenanthrol, monometh'yl'ether of catechol, methoxyphenol, phenoxyphen'ol; chlorphenol, and the like; Preferenceingeneral is to the monohydroxy phenols otherwise unsub stituted, particular preference being givento phenol and alpha and beta naphthol.

The hydroxyaromatic compounds may also con tain one or more substituent groups such as'car boxyl, metal carboxylate, halogen, nitro, amino and the like; here again, any substituent which does not take a predominant part in the conden-i sation with the aldehyde and the heterocyclic amine. Preferred vof such substituents are carboxyl and metal carboxylate groups.

As indicated hereinabove-the'hydroxyaromatic compound may contain one or more'alkyl sub stituents, such as short-chain groups typified by methyl, ethyl, amyl, etc.; orldng-chain, relatively high molecular weight hydrocarbon groups having at least twenty carbon atoms, typified by alkyl groups derived from petroleum wax, which is a predominantly straight-chain aliphatic hydrocarbon oiat least'twentycarbon atoms. {It will be obviousto those ski-ll'ed'inthe-art that the maximum 1 number of alkyl groups is "limited by 4 the number of valences on the aromatic nucleus available for substitution. Naturally, the maximum number of such groups which can be attached to a single aromatic nucleus will vary as the nucleus is monoor poly-cyclic and as the nucleus is otherwise substituted, with such groups as. carboxy; nitroa amino halogen and the like. "A- typical} and *also preferred; alkylsubstituted hydroxyaromatic compound which may be used isa wax-substituted phenol, wax-phenol. The termjfwax as used herein designates petroleum waxes aliphatic hydrocarbons or hydrocarbon i 5 groups ofthe typeiwhich characterize petroleum wax: Tl'i'esesocalled wax substituents may be 16 'ob'taihedb'y alkylation of the phenol or hydroxyv.ammatic hydrocarbon with a relatively high L molecular weight aliphatic hydrocarbon or mixwax) byany suitable alkylation procedure such, for example, as by a Friedel-Crafts condensation of chlorinated petroleum wax with phenol.

The condensation products are b'elievedto be formed 'inithe manner indicated in the following equation, wherein formaldehyde, phenol and Iiiorpholine are used as illustrations:

Inpreparing the condensation products, the reactants may be added to each other in any. I order.

aldehyde to an alcohol solution of the hydroxyaromatic compound andthe heterocyclic amine. The reaction may also be carried out in thepresence of other diluents or solvents such, for example, as benzol, chlorbenzene, tetrachlorethane; mineral oil, etc. In the event that mineral oil is used as a diluent, the mineral oil may be retained, rather thanseparated from the condensation product, thereby providing a mineral oil concentrate which may be reacted with a sulfurizing agent. Oil concentrates of the sulfurecom taining reaction products, and metal sa'lts'there of, are similarly obtained.

The reaction temperature may be varied con-'- siderably, dependingupon the time ofreaction, the. specific-reactants used, etc. For example, the reactionican' beicarried out at 20-25 C. for a relatively long period of time or at the refiux temperature of the reaction mixture over acornparativelyrshortperiod. By way of illustration, the-reactants in quantities such as shown in the following example, may bethoroughly mixed at 20-25" C. for several hours and the reaction completed at'the reflux temperature of the reaction mixture for an additional period of several hours.

The condensation product may be Water washed'to assure "complete removal of any unreacted amine and this is recon'imen'ded when the amine is high boiling. In general, however, the procedure involvesdistilli'ng ofl the solvent which also removes any unreacted amine, water of reaction and water added-withthe-reactants ,ture of. such hydrocarbons (such as petroleum A typical-procedure involves adding'the (formaldehyde, for example,.is generally used in a 37% aqueous solution). i 1

The ratio of "the reactants used may be varied to provide: one or moremethylene heterocyclicamine groups; 1

Metal salts of the condensation products may be prepared by any of the well-known procedures for replacing a hydroxyl or carboxyl hydrogen or both. Typical methods include: addition of an alcohol solution of a metal oxide or hydroxide to thecondensation product; addition of a metal alcoholate in alcohol solution to the condensation product; addition of an alcohol solution of a metal salt to the sodium salt of the condensation product'followed by removal of the alcohol and the sodium salt formed by double decomposition; etc.

As indicated hereinabove, the reaction products contemplated herein are prepared by reacting a condensation product of the type described above with elementary sulfur, a sulfur-halide or a mixture' thereof. This reaction is preferably carried out in the presence of an inert diluent such as tetrachlorethane, benzene, chlorbenzene, mineral oil, etc. These diluents-except heavy mineral oilsare removed after the reaction by distillation of the reaction mixture which contains the desired reaction product. When mineral oil is used'as the diluent, however, it may be retained, thereby providing a mineral oil concentrate=containing the reaction product. 1

The reaction temperature may be varied considerably, depending upon the reaction time and the specific sulfurizing reactant used. Generally, higher reaction temperatures and longer reaction times are required when elementary sulfur is used than when a sulfur halide is used. The preferred procedure involves adding the sulfurizing reactant to the condensation product at 2il-25 C. and thereafter heating the reaction mixture so formed at the reflux temperature of the diluent for several hours. Preference is given the sulfur halides and, of these, sulfur monochloride is particularly preferred.

Metal salts of the aforesaid sulfur-containing reaction products, as indicated above, also fall within the scope of the present invention. Any metal'may be used the oxide or hydroxide of which (in alcohol solution, if necessary) can be reacted with the intermediate condensation product,- or a salt of which can be reacted in alcohol solution with the sodium salt of the intermediate product. Among the metals contemplated for this purpose are: copper, beryllium, magnesium, calcium, strontium, barium, radium, zinc, cadmium, mercury, germanium, tinylead, vanadium, chromium, manganese, iron, cobalt, nickel, ruthenium, palladium, platinum, aluminum, antimony, arsenic, bismuth, cerium, columbium, gallium, gold, indium, iridium, molybdenum, osmium, ru-

bidium, selenium, tantalum, tellurium, thorium'-,-

titanium; tungsten, uranium, and zirconium? Preference isgiven to metalsnof-th'e alkaline-earths group, particularly:tombarium. As noted above; the metal is preferably'iintroduced by reaction of its oxide or; hydroxide with the-intermediate:condensation product. Where necessary,.aarria'lcohol solution of the oxide oils-hydroxide is used. The metal salts can also be prepared by reacting thesodium salt of the intermediate product with an alcohol solution of a salt of the desired'metal, such as stannous chloride, lead acetate, thorium nitrate, titanium tetrachloride, etc.

These metal salts may be prepared by any of the procedures'referred to hereinabove;for%in-' troducing metal into the intermediate or reaction products.

The sulfur-containing reaction products are illustrated by. the following typical example.

: 7 EXAMPLE Fifty grams of wax-phenol (2-18), prepared as described in U.-S. Patent No. 2,191,499, and 7.7 grams'of morpholinetwere dissolved in butyl alcohol, and 14.6 grams of Formalin (37%) 'wereaddeddropwise thereto, addition taking about 20- minutes.- The reaction mixture thus obtained: was stirred forZ /Z hours at room temperature,

20-25? C., and thereafter heated at reflux,

C., for 8-hours. Benzol was added to thereaction mixture, and was removed therefrom, with butyl:alcohol and water ofreaction and added water of the Formalin used, by distillation to a maximum temperature'of C. at 10 m'ms. pressure. The reaction product thus obtained was wax hydroxy benzyl morpholine (2-18); nitrogen analysis revealed 1.7%.nitrogen, compared with a theoretical nitrogen content of 2.0%.

Fortygrams of wax hydroxy benzyl morpholine (2-18) was blended in 80 grams ofmineral oil (S. U. V. of 65 secondsat 210 F.) and Stoddard, Solvent. chlorbenzene were added slowly during'a- 30-min ute period to the mineral oil-Stoddard Solvent blend, being introduced below the liquid surface.

:' The'reaction mixture thusobtained became viscous whereupon additional chl-orbenzene was addedthereto; There was no evolution ofI-ICl" gas and, for-this'ueason, the reaction mixture was washed with sodium acetate solution 'to remove any-HClassociated with ail-amino group; Thereafter, the reaction mixture was filtered through Hi-Flo' clay and thefiltratetherefrom' was distilled to a maximum temperature of 180* C. at l0 'mms. pressure, thereby removingStod dard Solvent and chlorbenzene. The reaction productProduct"One-is a 1 t 2' mineral oil blend and contains nitrogen andsulfur.

' As stated hereinbefore, the reaction products contemplated by this invention and illustrated by the above example, when added to lubricating oils in minor proportions, have been found to improve these oils in several important respects. This phenomenon is demonstrated by the following tables, which give the results of the various-tests conducted to determine the effectiveness of these" oil-:in -the-.followingf tables is-the per cent of concentratedmaterial and does not include the oil in which time product, was made.

R UR POINT DEPRESSION Testswere conducted in the conventional manner' 'to determine th'e Ai- 'Su pouripoin'ts of blends od these' reactiorr products with a Mid Four grams of sulfur monochloride in A. S. 'l. M. Pour Point Values Addition Agent Per Cent None Product One Do SocoNY-VAcUUM TURBINE Tns'r added 1 gram of iron granules and 24 inches of 18 gauge copper wire. The samples were then heated to a temperature of 200 F, with 5 liters of air per hour bubbling therethrough. Two cc.

of distilled water were added each day. The results of the tests which were made for color and acidity or neutralization number and amount of sludge'formed after certain time intervals are set forth in Table II below.

Table II Per Cent Sludge Added Addition Agent Hours g,' g, N. N. (in mom) None 17. 8 Product 0nc OPERATION TEST To demonstrate the effectiveness of the reaction products under actual operating conditions of an automotive engine, unblended oils and improved oils, containing the reaction products, were subjected to the Lauson engine test. The tests were carried out in a single-cylinder Lauson engine operated continuously over a time interval of 16 hours with the cooling medium held at a temperature of about 212 F., and the oil temperature held at about 280 F. The engine was operated at a speed of about 1830 R P. M. At the end of each test the oil was tested for acidity (N. N.) and viscosity. The base oil used here is a solventrefined oil having an S. U. V. of 44 seconds at 210 F.

- Table III .Per Cent Addition Age Added i suvni 210F. k

None Product One one used in their preparation and present in the reaction product.

The amount of improving agent used varies with the mineral oil fraction with which it is blended and with the properties desired with the final oil composition. These reaction products, and the metal salts thereof, may be added to mineral oil in amounts of from about 0.01% to about 10%, but amounts of 0.1-5% generally provide satisfactory improvement.

It is to be understood that although I have described certain preferred procedures which may be followed in the preparation of the novel reaction products contemplated herein as multifunctional addition agents for mineral oils and have indicated representative reactants for use in their preparation, such procedures and reactants are merely illustrative and the invention is not to be considered as limited thereto or thereby but includes within its scope such changes and modifications as fairly come Within the spirit of the appended claims.

Iclaim:

1. An improved mineral oil containing a small proportion, sufficient to inhibit said oil against the deleterious eiTects of oxidation, of an oilsoluble, sulfur-containing reaction product obtained by reacting (1) two molar equivalents of a condensation product of the general formula on Iii R'Fa- CY in which A is an aromatic nucleus; R is selected from the group consisting of hydrogen, alkyl, aralkyl, alkaryl, aryl, cycloalkyl, alkoxy and aroxy groups; (1 represents the number of R groups attached to the aromatic nucleus A and varies from 0 to 3; M is selected from the group consisting of hydrogen and metal; R is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, cycloalkyl and aryl groups; Y is a secondary heterocyclic amine group attached at the nitrogen atom thereof to the carbon atom of the group; and 0 represents the number of groups attached to the aromatic nucleus A and varies from 1 to 3; with. (2) about one molar equivalent of a sulfurizing material selected from the group consisting of elementary sulfur, a sulfur halide and a mixture thereof, in the presence of an inert diluent, at a temperature falling within the range varying between about 20 C. and the reflux temperature of the diluent and for a time sufficient to effect sulfurization of said condensation product.

2. An improved mineral oil containing a small proportion, from about 0.01 per cent to about 10 per cent, of an oil-soluble, sulfur-containing reaction product obtained by reacting (1) two molar equivalents of a condensation product of the general formula in which A is an aromatic nucleus; R is selected taceegere -fromithe-group consisting-of:hydrogen; =alkyl,. ar- -a1kyl',':alka-ryl,raryl cycloalkyh'alkoxy and aroxy roups'; 1a representsthenumbenof R groups attached :to i the aromatic 'nucleus A and waries from to 3; lvLis selected from the group con-' sisting of hydrogen and metahR is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, cycloalkyl and aryl groups; Y is a sec- :endary heteroeyclic amine-group: attached: at. the

.nitrogenuatom;thereof,to the carbon=;.ato m o the .group; and c representsthenumber of groups attached to the aromatic nucleus A and varies from 1 to 3; with (2) about one molar equivalent ofrazsulfurizing material selected: from the group consisting of elementary sulfur, a sulfur halide and a mixture thereof, in the presence of an inert diluent, at'a temperature falling within the range varying between about 20 C. and zthe reflux temperature. of ,the; diluent, and, for a ttimegsuificient to efiectrsulfurizyation i said orildensation, product. c

.13. *An improved mineral ,oilcontali ning :pmportion, *TSHfiiCiQIlt to [inhibit said, oil against =:.the, deleterious effects of; oxidation or nanoilnsoluble, sulfur-containing reaction product ob- :tainedaby meeting. ('1) a two, molar equivalents of a condensation product of the general; formula ;,inwhichrA is an aiiomaticrnucleus; 3 is, selected from the group consisting of ,drog n- ,,alkyl, aralkyl, ,alkaryl, .aryl, cycloalkyl, alkoxy and aroxy groups; a represents the number of R groups attached to the aromatic nucleus r-Amnd varies from 0 to..3; M. is selected -fromtthe group consisting of hydrogen .andwmetal; R istselected I from 'the group consisting of hydrogenmalkyl, alkaryl, .aralkyl, cycloalkylandiaryl groups;i- Y is a secondary heterocyclic. aminergroupfattached at the nitrogen atom .thereof-to the carbonatom of-the a 2.x

l .4 It

group; and e represents the number of Pd-O-El I 110 I :iita'ned by -reacting: (1) tWo molar equivalents o condensationproduct of the general formula 0M it REA in which Ais an aromatic nucleus; R is selected from the group 1 consisting of hydrogen, alkyl, aralkyl, alkaryl, aryl, cycloalkyl, alkoxy and aroxy groups; a represents the number of R :groups-v attachedsto the: aromatic nucleus A and tvaries' from-'0 to' '3; is selected from' the group 1 consisting of 'hydrogen -and metal; R I is selected from the group consistingof hydrogen, alkyl,

* alkarylg aralkyl,rcycloalkyl and aryl groups; Y

is a secondary heterocyclic amine :group attached "atthe nitrogen atom thereof to the carbon atom dfthe 2 I I z: J1

t group; and c representsrthe number of groups attached to thearomatic nucleus A and varies from 1 to 3; with (2) about one molar equivalent of sulfur monochloride, in the pres- -ence of an inert diluent, at a 1 temperature falling =wi'thin-tlre range varying between about C. and the refiux temperature of the diluent and for a ti-ine suflicient' to efiect=-sulfurization of said *conden'sation productl ;Q-5. -An improved mineral oil containing a small -proporti'on,'-sufiicient to inhibitsaid oil against the deleterious effects -of-- oxidation, of an oilsoluble; sulfur containing reaction product 010- I tained by reacting (1) twomolar equivalents of 'a conden-sation productfof' the general'formula in w chAjisan aromatic'hucleus; Ris selected f the group consisting of'hydroge'n, "alkyl, lla k yl aryl "c c o yt, a y and p3, v yap sjrornoto mlMis selected fromthe group consisting of" hydrogen and metal; "R is: selected ,fromthe ,ereupeqnsis iu o hydro en, al yl," ljalkarvlfi elkyl;,cyclqalkyland aryl groups; Y

is a. secondary heterocyclic amine groupattached at the nitrogen atom thereof to the carbon atom of the group; and c represents the number of H e as e y i groups attached to the aromatic nucleus A and varies from 1 to 3; with (2) about one molar equivalent of elementary sulfur, in the presence of an inert diluent, at a temperature fallin Within the range varying between about 20 C. and the reflux temperature of the diluent and for a time sufficient to effect sulfurization or said condensation product.

y grou'psyd repr'esentsj'the number of R 6. An improved mineral oil containing a small proportion, sufiicient toinhibit said oilv against the deleterious effects of oxidation, of an oilsoluble, sulfur-containing reaction product obtained by reacting (1) two molar equivalents of a condensation product of the general formulain which A is an aromatic nucleus; R is a paraflin wax hydrocarbon group containing at least twenty carbon atoms; a represents the number of R groups attached to the aromatic nucleus A and varies from to 3; M is selected from the group consisting of hydrogen and metal; R is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, cycloalkyl andaryl groups; Y is a secondary heterocyclic amine group attached at the nitrogen atom thereof to the carbon atom of the group; and 0 represents the number of groups attached to the aromatic nucleus A and varies from 1 m3; with (2) about one molar equivalent of a sulfurizing material selected from the group consisting of elementary sulfur, a sulfur halide and a mixture thereof, in the presence of an inert diluent, at a temperature falling within the range varying between about 20 C. and the reflux temperature; of the diluent and for a time suificient to effect sulfurization of said condensation product.

7. An improved mineral oil containing a minor proportion, suflicient to inhibit said oil against the deleterious efiects of oxidation, of an oilsoluble, sulfur-containing reaction product obtained by reacting about two molar equivalents of a paraffin wax-hydroxy-benzyl morpholine with about one molar equivalent of sulfur monochloride, in the presence of an inert diluent, at

a temperature falling within the range varying V between about 20 C. and the reflux temperature proportion, suflicient to inhibitsaid oil against the deleterious effects of oxidation,-of an oilsoluble, sulfur-containing reaction product obtained by reactin (1) two molar equivalents of a condensation product of the general formula in which A is an aromatic nucleus; R is selected from the group consisting of hydrogen, alkyl, aralkyl, alkaryl, aryl, cycloalkyl, alkoxy and aroxy groups; or. represents the number of R groups attached to the aromatic nucleus A and varies from 0 to 3; R is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, cycloalkyl and aryl groups; Y is a secondary heterocyclic amine group attached at the nitrogen atom thereof to the carbon atom of the group; and c represents the number of EDWARD A. OBERRIGHT.

REFERENCES CITED 'Th e following references are of record in the file or this patent:

.- UNITED STATES PATENTS Number Name Date 2,263,445 Reiii Nov; 18, 1941 2,282,710 Dietrich May 12, 1942 2,322,379 McCleary June 22, 1943 2,334,594 Zimmer Nov. 16, 1943 2,336,006 Fuller Dec. '7, 1943 2,340,036 Zimmer Jan. 25, 1944 2,353,192 Sargent et al. July 11, 1944 2,363,134 McCleary Nov. 21, 1944 Certificate of Correction Patent N 0. 2,459,116. January 11, 1949.

EDWARD A. OBERRIGHT It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 12, line 30, claim 8, after the word from" insert the group;

and that the said Letters Patent should be reed with this correction therein that the same may conform to the record of the case 111 the Patent Oifice.

Signed and sealed this 14th day of June, A. D. 1949.

THOMAS F. MURPHY,

Assistant Oammz'ssioner of Patents