Патент USA US2408906код для вставки
2,408,905 Patented Oct. 8, 1946 UNITED STATES PATENT OFFICE 2,408,905 PREPARATION OF SYNTHETIC GLYCERIDES Howard C. Black and Charles A. Overley, Chi cago, 111., assignors to Industrial Patents Cor poration, Chicago, 111., a corporation of Dela ware No Drawing. Application November 29, 1941, Serial No. 420,942 9 Claims. (Cl. 260—d10.6) 1 2 This invention relates to the preparation of chemically pure esters of polyhydroxy compounds ing one unsaturated bond are the acids of the and unsaturated acids. ' oleic acid series such as acrylic, crotonic, angelic, tiglic, methacrylic, lauroleic, myristoleic, palmi ’ toleic, oleic, erucic, brassidic, elaidic and ricin oleic acids. Examples of monocarboxylic acids having two unsaturated bonds are the acids of 'One of the objects of this invention is to pro vide a method for the synthesis of pure esters of polyhydroxy compounds, for example, polyhy droxy alcohols, and unsaturated organic acids. Other objects and advantages of this inven— tion will become apparent from the description and claims which follow. It has been found difficult to produce pure es ters of unsaturated acids and polyhydroxy com the linoleic acid series, such as tariric and linoleic acids. Examples of monocarboxylic acids hav ing three unsaturated bonds are linolenic and 10 elaeostearic acids. Examples of dicarboxylic acids, having one unsaturated bond are aconitic,_ itaconic, citraconic, maleic and fumaric acids. The unsaturated acid is ?rst brominated to protect the unsaturated bonds. The bromine ad pounds, for example, glycerol, by direct esteri ?cation due to oxidation ‘and polymerization of the unsaturated acids at the unsaturated bonds 15 dition product is then converted to an acid chlo ride by the use of, for example, thionyl chloride, during the attempted synthesis. To facilitate the esteri?cation and prevent oxidation and poly merization of the unsaturated acids during the phosphorus trichloride or phosphorus pentachloa ride. In the preparation of glycerides, for ex ample, the acid chloride of the bromine addition chlorides or anhydrides of the unsaturated acids 20 product is then dissolved in a solvent in which, glycerol or acetoneglycerol and a nitrogenous before reacting the materials with the polyhy base is also soluble, such as chlorinated hydro‘ droxy compound. In forming the acid chlorides carbons, for example, dry chloroform, carbon tet or anhydrides of the unsaturated acids, oxida rachloride, ethylene dichloride, and acetylene tet tion, polymerization and ‘decomposition of the acids at the unsaturated bonds occur, and yields 25 rachloride. The purpose of employing a solvent is to produce a single homogeneous phase of the of pure acid chlorides or anhydrides of the un reaction mixture. 'If the solvent is not employed, saturated acids are low. After the pure acid mixing of the reagents is difficult. chloride or anhydride has been produced, some Acetonegl'ycerol ‘is a condensation product oxidation and polymerization of the unsaturated bonds occur during the reaction of the acid chlo 30 formed by the reaction of glycerol and acetone in reaction, it has been proposed to form the acid the presence of anhydrous sodium sulphate and ride or anhydride with the polyhydroxy com hydrochloric acid. Two of the hydroxyl groups pound. The resulting synthetic esters of the poly hydroxy compound and the unsaturated, acids of the glycerol are thereby covered or removed from the sphere of reaction, leaving but one hy consist of a variety of individual compounds and the product is not a pure ester of the polyhy 35 droxyl group free to react with the acid chloride of the bromine addition product, and the for droxy compound and the unsaturated acids. mation of the‘ monoacid ester is thereby assured. The present invention contemplates the prep The formation of acetoneglycerol may be repre aration of the acid chlorides of bromine addition sented by the following equation: . products of unsaturated acids, which are then reacted with the polyhydroxy compound, and 40 the subsequent removal of the bromine to yield the pure ester of the polyhydroxy compound and the unsaturated acids. The method of the pres ent invention may be employed, for example, in the preparation of pure synthetic monoacid, di acid, and triacid esters‘of glycerin and unsatu rated acids, monoacid and diacid esters of eth ylene glycol, monoacid and diacid esters of di ethylene glycol, and ‘the like. This method may also be employed in preparing mixed glycerides H2 0 OH 0 H3 / —-—» \ 45 H2OOH Glycerol 50 55 HO O Nazs 0 4 HCOH + O=C of unsaturated “acids ‘and mixed glycerides of saturated and unsaturated fatty acids. , The method of this invention is applicable to the preparation of any ester of a polyhydroxy compound and unsaturated organic acids. Ex amples of monocarboxylic unsaturated acids hav H2 C O H C ‘ H Cl CH3 0 Hz \ / + H20 / \ ' H200 Acetone (_1) CH3 Acetoneglycerol The solution of the acid chloride of the bro mine addition product is then added to a cold mixture of acetoneglycerol and quinoline, or other suitable nitrogenous base, such as pyridine, ani line, and the like. Quinoline, or other nitrog enous base is employed to react with the hydrogen chloride liberated by the reaction between the acid chloride of the bromine addition product and acetoneglycerol. ' . 2,408,905 l 3 4 The mixture is allowed to stand for a number of hours and is then taken up in ether and washed successively several times with cold dilute sul phuric acid, saturated sodium bicarbonate solu small proportions through the condenser over at period of about one hour to convert the tetra-i bromostearic acid into 9, 10, 12, 13-t/etrabromo- , stearoyl chloride which may be represented by tion, and water. The ether solution is dried over anhydrous sodium sulphate and is then held at a low temperature to precipitate the ester formed by the reaction between the acid chloride of the the formula RCOCl. The mixture was then al lowed to cool to room- temperature and held at room temmrature over night. The oily mass was taken up in about 250 cc. of anhydrous petroleum ether and the solution bromine addition product and acetoneglycerol. The ester may be removed by ?ltration and re 10 was then cooled to about —26 degrees C., and held at this temperature for several hours. The tetra crystallized from a mixture of equal parts of ether and petroleum ether. The ester formed by the reaction of the polyhydroxy compound and the bromostearoyl chloride crystallized into shiny acid chloride of the bromine addition product ‘ perature and washed with cold petroleum ether white ?akes which were ?ltered at the low tem until most of the excess thionyl chloride was re may be liberated from the acetone condensation moved. The product was then carefully dried product by replacing the hydroxyl groups in the glycerol or polyhydroxyl part of the reaction under vacuum. If desired, the tetrabromostear oyl chloride may be recrystallized from anhydrous product or hydrolyzing the reaction product by ether or petroleum ether. The yield of product dissolving the crystallized or precipitated material in ether and adding cold concentrated hydro 20 in following the procedure set forth was rI8 grams of tetrabromostearoyl chloride. chloric acid. In the preparation of the monoacid ester of The mixture may be allowed to stand over night at low temperatures to crystallize the glycerol and linoleic acid, a cold mixture of 10 grams (0.075 mole) of acetoneglycerol and 9.6 brominated ester, after which the ester may be ?ltered from the liquor and washed free of chlo 25 grams (0.075 mole) of quinoline was placed in a rides with cold water. The ester may then be glass stoppered flask, and 45 grams (0.073 mole) dried in a vacuum and recrystallized from ether, of tetrabromostearoyl chloride dissolved in 20 cc. if desired. of dry chloroform added to the cold mixture of acetoneglycerol and quinoline in small portions The brominated ester is then debrominated by treatment with zinc and anhydrous alcohol. 30 while cooling and agitating the mixture. The Other solvents may be employed in place of al mass was then allowed to stand for about forty eight hours at room temperature. cohol, such as benzene, toluene and xylene, but We prefer to employ alcohol. The alcohol may be The slight excess of acetoneglycerol is em re?uxed and the zinc removed by ?ltration. The ployed to insure that no free acid chloride re ?ltrate is washed several times with water and mains in the reaction mixture. Free acid chlo ?nally dried over anhydrous sodium sulphate and ‘ ride will be converted into the free fatty acid evaporated in vacuo. The liquid is then taken when the product is taken up in ether and washed up in a mixture of equal parts of ether and v with water. The fatty acid is more di?icult to petroleum ether and is allowed to crystallize at separate from the ester than the acetoneglycerol. reduced temperatures. The crystals of pure un 40 Equimolar quantities of the acid chloride and saturated esters may be removed from the liquor acetoneglycerol, however, may be used. A slight by ?ltration, and then dried. excess of quinoline is also employed to insure a By way of illustration, but not by way of limi complete removal of the hydrogen chloride tation, the present method is speci?cally described formed by the reaction. in the preparation of monoacid, diacid, and tri 45 The reaction may be represented by the follow ing equation: acid esters of glycerol and linoleic acid. The bromine derivative of linoleic acid, namely, tetrabromostearic acid, was prepared by bromina tion of the acetone soluble fraction of cottonseed oil fatty acids. The acetone soluble fraction of 50 cottonseed oil fatty acids was obtained by dissolv ing the mixture of fatty acids derived from cot tonseed oil in about 4 volumes of acetone. The solution was then cooled to —15 degrees C. and maintained at this temperature for several hours. The precipitated acids were removed by ?ltration, and the acetone in the ?ltrate was removed by evaporation. The acids obtained by evaporation of the acetone were dissolved in dry petroleum ether and bromine added while maintaining the 60 mass at about 20 degrees C. and continuing the bromine addition until no more bromine was ab sorbed. The tetrabromostearic acid separated in white crystals which were removed by ?ltration, and puri?ed by recrystallization from a mixture of ether and petroleum ether. The bromine de rivative of linoleic acid is 9, 10, 12, 13-tetrabromo stearic acid and may be represented by the for mula RCOOH. In a speci?c example, 80 grams of tetrabromo H 0 CE 2 110001 itJ,t10,bl2, 13e rs romo stearoyl chloride + H3O \ / OCH + Quinoline /C\ 0 H30 ——-> B1 Acetoneglycerol R C 0 O CH: [BC 0 CH \C/ 113C / \ + Quinoline-HCI (2) 0 CH2 Ester of brominated acid and accloncglycerol The material was taken up in about 150 cc. of cold ether and washed successively several times with cold 0.5 N sulphuric acid, saturated sodium bicarbonate solution, and water. The ether solu tion was dried over anhydrous sodium sulphate and was then cooled to about —26 degrees C. The gummy precipitate was ?ltered and recrys tallized from a mixture of ether and petroleum ether at a temperature of about —26 degrees C. be yield was about 35.5 grams of the ester. The monoacid ester of glycerol and tetrabromo stearic acid was placed in a flask and heated in an stearic acid was liberated from the acetone con oil bath to a temperature of about 120 de— grees C. The ?ask is preferably provided with a groups in the glycerol part of the ester or by hy densation product by replacing the hydroxyl re?ux condenser, and after the acid has been drolyzing the reaction product by dissolving the melted, 15 grams of thionyl chloride was added in 75 recrystallized precipitate in about 300 cc. of ether, 2,408,905, 5 cooling the liquid in an ice bath, and adding about 360 cc. cold concentrated hydrochloric acid in portions while vigorously agitating the mass. The mixture was then cooled to about —.26 de grees 0., and the semicrystalline solid ?ltered and washed free of chlorides with cold water. H2(|'J.OH HOOH + 01 The I solids were then dried under vacuum and, re H2O OH crystallized from about 500 cc. ether at zero de Glycerol CG + pyridine Dry _-_> I grees C. The recrystallized product appeared as plates when examined under a high powered mi 10 croscope. The yield was 26 grams of the mono 'l‘riphenylmethyl chloride acid ester of glycerol and tetrabromostearic. acid. The replacement of the hydroxyl groups, or the hydrolysis of the reaction product,‘ or the libera tion of the monoacid ester of glycerol and tetra bromostearic acid from the acetone condensa tion product may be represented as follows: RC 0 0 ?H2 (3) H30 H3O \ / 0011 Ether OCHz H2COOOR H1O OH Monoacid glyceride 7 . H2? OH H? OH HzCO-———(IJ——C> + Pyridine-H01 CH3 I 9 l 1 13' CH3 Acetone a-monotrytylglycerol A cold mixture of the above described glycerol derivatives and quinoline in the proportion of about 1 mole of glycerol derivative to 2 moles of quinoline was placed in a glass stoppered flask and tetrabromostearoyl chloride dissolved in dry o tetrabromosteanc acid The monoacid ester of glycerol and tetrabro mostearic acid was then debrominated t0 rees tablish the unsaturated bonds by treating‘ 20 gram portions of the tetrabromo derivative with 20 grams of ?nely granulated zinc and 50 cc anhy drous alcohol. The granulated zinc is first thor oughly washed with dilute hydrochloric acid and then with water and carefully dried before use. After mixing the tetrabromo derivative, zinc, and anhydrous alcohol in a ?ask, the mixture was chloroform was added to the cold mixture in small proportions While cooling and agitating the mix ture. The quantity of tetrabromostearoyl chlo ride added was slightly in excess of two moles. A slight excess of the tetrabromostearoyl chloride is employed to insure that no free hydroxyl groups remain in the glycerol derivative, and insure an esteri?cation of both hydroxyl groups. Free acid chloride will be converted into free fatty acid when the product is taken up in ether and washed with water. The fatty acid is easier to separate from the diacid ester than the monoacid esters of glycerol which are formed when less warmed gently in a Water bath until a vigorous exothermic reaction occurred and the ?ask of material was then transferred to an, ice bath. The ?ask was ?tted with a re?ux condenser and the alcohol re?uxed for about one half hour. The zinc was then removed by ?ltration. The ?ltrate was taken up in ether and washed several times with water to remove the alcohol and any than 2 moles of acid are used in the reaction. However, the acid chloride and the glycerol de rivative may be employed in the proportion of inorganic substances which may be present, and ?nally dried over anhydrous sodium sulphate. 2 to 1, if desired. A slight excess of quinoline is The liquid Was then evaporated under a vac preferably employed to insure a complete removal of the hydrogen chloride liberated by the reac tion. The reaction may be represented by the follow uum, and the nearly colorless oily material was taken up in 30 cc. of a mixture of equal parts of ether and petroleum ether and cooled to about —-26 degrees C. (5) The solution was held at this temperature over night to crystallize the ester. The crystals were removed by ?ltration and dried at a low temperature. On raising the tempera ture of the dry crystalline material to about room temperature, the crystals melted to form a color less viscous oil. The yield of monoacid ester of ing equation: . H 0 CH2 RC 0 01 glycerol and linoleic acid was about 8.9 grams. The iodine value of the synthetic monoacid es ter of glycerol and linoleic acid was 142.1, where as the calculated iodine value for the pure ester (ill is 143.3. The saponification value of the ester was 158.5 whereas the calculated saponi?cation value for the ester is 158.3. The melting point of the I + , .O\ HO OH R C 0 01 I Tetrabromo- \ + quinoline ———-> I O-GH; orll’lOnOIJl‘Ytyl stearoyl chloride glycerol ester was determined as being 14.0-15.0 degrees C. In the preparation of the diacid esters of glycerol and linoleic acid, a-Il'lOlflOlOdOhYdflll or a-monotrytylglycerol may be used. The forma tion of these glycerol derivatives may be repre sented by the following equations: RC 0 O CH: _ ' R000 CH + quinoline-HCl 70 Glycerol Hydrogen iodide a-monoiodohydrin 75 Ester of brominated acid and wmonotrytylglycerol (6) 2,408,905 7 8 The reaction mass is then allowed to stand at over anhydrous sodium sulphate. This procedure room temperature for about 48 hours. The mass is then taken up in cold ether and washed suc is suf?ciently vigorous to cause the a-, ?-diacid cessively several times with cold dilute sulphuric acid, saturated sodium bicarbonate solution and 04-, a-diacid glyceride. The dried ?ltrate may then be evaporated un der a vacuum and the only residue may be taken up in a mixture of equal parts of ether and petro leum ether and cooled to about —26 degrees C. The solution may be held at this temperature over night to crystallize the diacid esters of glycerol and linoleic acid and the crystals may then be removed by ?ltration and dried at a low tempera ture. On raising the temperature of the dry crystalline material to about room temperature, the crystals melt to form a colorless viscous oil. In the preparation of the triacid ester of glycerol and linoleic acid, in a speci?c example, a cold mixture of 2.2 grams (0.024 mole) glycerol and 9.6 grams (0.075 mole) quinoline was placed in a ?ask, and 45 grams (0.073 mole) tetrabromo stearoyl chloride dissolved in 30 cc. dry chloro form was added in small portions While cooling and agitating the mixture. The semisolid mass was permitted to stand at room temperature for two days and then taken up in 600 cc. of ether. The solution was then washed successively with water. glyceride to be at least partially converted to the The ether solution is then dried over anhydrous sodium sulphate and cooled to about —26 degrees C. The precipitate may be ?ltered from the ether solution and recrystallized from a mixture of ether and petroleum ether at a 10 temperature of about —26 degrees C. The diacid ester of glycerol and tetrabromo stearic acid may be liberated from the ester of the triphenylmethyl glycerol condensation prod uct by dissolving the recrystallized precipitate in 15 ether, cooling the solution in an ice bath, and adding hydrogen chloride in portions while vigor ously agitating the mass. The mixture may be then cooled to and held at about —26 degrees C. and the semicrystalline ester ?ltered and washed 20 free of chlorides with cold water. The ester may be then dried under vacuum and recrystallized from ether. The liberation of the diacid ester of glycerol and tetrabromostearic acid or the replacement as of the hydroxyl groups in the glycerol part of the ester may be represented as follows: RCOOCH: 0.5 N sulphuric acid, saturated sodium bicarbon ate solution and water. The ether solution was then dried over anhydrous sodium sulphate and 30 cooled to a temperature of about zero degrees C. The liquid was held at this temperature over night, and the crystals which were formed were removed by ?ltration and recrystallized from ether. The recrystallized material appeared to 35 be needlelike in form under a lower power micro ether ROOOOH + H01 --—> Geo-em scope and appeared to be long thin plates under high power. The yield was 30.5 grams of glycerol tritetrabromostearin. (7) The slight excess of acid chloride is employed 40 in preparing triacid glycerides to insure the esteri?cation of all hydroxyl groups of the glycerol and to insure that no monoacid or diacid glyc HzCOOCR erides remain in the product. The free fatty acid ‘La LI formed from the excess acid chloride when the product is taken up in ether and washed with water is separated with greater facility from the triacid glyceride than monoacid and diacid glyc erides. Equimolar quantities of the acid chloride tetrabromo stearic acid and glycerol, however, may be used. A slight ex Triphenyl-metliyl 550 cess of quinoline is employed to insure a complete chloride removal of the hydrogen chloride formed by the reaction. Although, in the equations above, the use of The reaction may be represented by the follow u-monotrytylglycerol has been illustrated, it is ing equation: apparent that a-monoiodohydrin may be repre Diacid glyceride of sented in a similar manner. However, in the re moval of iodine from the ester of a-monoiodo hydrin, the conditions are sui?ciently vigorous to cause rearrangement of the acid radicals to form the (1-, a-diacid glyceride. The iodine is removed by heating the iodine compound in alcohol in the 60 presence of silver nitrite. The diacid ester of glycerol and linoleic acid is formed by debrominating the ester of glycerol and tetrabromostearic acid, whereby the unsatu rated bonds are reestablished in the acid radicals. Debromination may be effected by treating the ester of glycerol and tetrabromostearic acid with ?nely granulated zinc and anhydrous alcohol. After mixing the glycerol derivative, zinc and an hydrous alcohol in a ?ask, the mixture may be warmed gently, for example, in a water bath, until a vigorous exothermic reaction occurs and the ?ask is then transferred to an ice bath. The zinc may be removed ‘by ?ltration and the ?ltrate washed several times with water and ?nely dried R C 0 01 HO OH: RC 0 C1 + HO OH + quinoline --> R O 0 Cl H 0 CH2 9,10,12,13stearoyl Glycerol tetrabromo chloride HzC-O 0 C R HC-O O C R + quinolino.HCl (8) HzC—O O C R Glycerol tritetra bromostearin The ester was then debrominated to reestablish the unsaturated bonds by treating 20 gram lots with 20 grams of ?nely granulated zinc and 50 cc. anhydrous alcohol. The zinc was ?rst washed with dilute hydrochloric acid, then with water, _ and carefully dried before being employed in this step. The ?ask was then warmed gently in a 2,408,905 10 9 . water bath until a vigorous exothermic reaction set in, and the flask was then transferred to an ice bath. The flask was ?tted with a reflux con denser, and the alcohol was re?uxed for about one half hour, after which the zinc was removed by ?ltration. The ?ltrate was taken up in ether and washed several times ‘with water and ?nally dried over anhydrous sodium sulphate and evap~ orated under vacuum. On dissolving the color less oil in a mixture of equal parts of ether and petroleum ether and holding the solution at —25 degrees C. over night, no crystals were produced. The solvent was removed by evaporation under which one of the hydroXYl groups is replaced ‘by linoleic acid and the other two replaced by lino lenic acid, the monoacid ester of the tetrabromo stearic acid and glycerol is ?rst prepared by re- , acting the tetrabromostearoyl chloride with the acetoneglycerol condensation product in the pres ence of nitrogenous base such as ,quinolin'e, as represented by Equation 2. The ester of tetrabromostearic acid and ace toneglycerol is then treated with water, ether and hydrochloric acid to liberate the monoacid ester of tetrabromostearic acid and glycerol, as illustrated in Equation 3. vacuum. The ester is then reacted with the hexabromo The triacid ester of glycerol and linoleic acid 15 stearoyl chloride in the presence of quinoline or had an iodine value of 171.2 whereas the calcu other nitrogenous base to form a mixed glyceride lated value for the ester is 173.3. The saponi?ca illustrated in the following equation: tion value of the ester was 191.2 whereas the cal~ culated saponi?cation value is 191.5. The melt ing' point of the product is 5.0-4.0 degrees C. 20 R’COCI That the acid radical of the esters prepared R’COOI by the above procedures is linoleic acid may be RCOOCH: HO H + quinoline --—> HOCHz easily determined by saponifying the esters by HzGOOCR treatment with 5 per cent alcoholic sodium hy HGOOCR’ + quinoline-HvCl droxide and isolating the fatty acid by acidi?ca tion and extraction with petroleum ether. For HzCOOCR’ (9) _ example, 6 gram samples of the monoacid ester and the triacid ester Were allowed to stand over The ester of glycerol and linoleic and linolenic night with 75 cc. of 5 per cent alcoholic sodium acids may be formed byv debromination of the hydroxide. The fatty acids were isolated by acidi 30 bromine derivative to reestablish the unsaturated ?cation and extraction ‘with petroleum ether. The acids so isolated may then be brominated and the tetrabromostearic acid may be identi?ed by a melting point determination. For example, the acids isolated from the esters as described above were brominated by taking 5 grams of the acid and brominating the acid bonds by treatment with ?nely granulated-puri ?ed zinc and anhydrous alcohol. The reactions, crystallization and drying » of the materials at the different stages in the proc css may be carried out as described above in the preparation of monoacid esters and triacid. esters of glycerol. in 80 cc. of petroleum ether at about 20 degrees It is apparent that if desired, a diacid glyceride C. The yield of the brominated product was 4.5 may ?rst be prepared by reacting the acid chlo grams of crystalline material, which had a melt ride with a-monoiodohydrin or d-monotrytylgly ing point of 115.5 degrees C. Similarly, 5 grams 40 cerol in the presence of quinoline, for example, of linoleic acid obtained by debromination of the as illustrated in Equation 6. vThe diacid ester tetrabrornostearic acid was brominated to yield of the brominated acid and the glycerol deriva 4.5 grams of crystalline material having a melt tive is then liberated from the condensation prod ing point or 115.5 degrees C. The tetrabromide uct to form the diacid glyceride of the bromi of the acid isolated from a mixture of the mono nated acid. The diacid glyceride of the bromi acid and triacid esters prepared as above also nated acid is then reacted with the acid chlo had a melting point of 115.5 degrees C. ride of the second acid in the presence of quinc In the preparation of mixed glycerides, for line to form the mixed triacid ester of glycerol example, triglycerides, containing two different and the two acids. The successive reactions may acid radicals, the monoacid glyceride of an acid be illustrated by the following’ equations: may ?rst be formed and the monoacid glyceride then reacted with an acid chloride of a di?erent acid. If desired, the diacid glyceride of an acid may first be formed and then treated with an acid chloride or" a different acid to form the B0001 HOG/‘H2 B0001 HOOH + quinoline —) mixed glyceride. If desired, each of the hy droxyl groups of .the glycerol may be replaced with a different acid radical. For example, the method of the present inven tion may be illustrated by the preparation of a 60 triglyceride in which one of the hydroxyl groups is replaced by linoleic acid and the other two hy droxyl groups may be replaced by linolenic acid. ‘The acids are ?rst lorominated to protect the unsaturated bonds. The bromine derivative of linoleic acid is 9, 10, 12, 13-tetrabromostearic acid. The bromine derivative of linolenic acid is 9, 10, 12, 13, 15, 16-hexabromostearic acid. The bro mine addition products are then converted into acid chlorides, namely, 9, 10, 12, 13-tetrabromo stearoyl chloride and 9, 10, 12, 13, 15, 16-hexa bromostearoyl chloride, which may be repre sented by RCOCl, and R’COCl, respectively. In the preparation of an ester of glycerol in 75 RC 0 0 CH1 R00 0 OH + quinoline'HCl (10) Geo-e 2408305 "11 12 The resulting product is then reacted with the acid chloride of the second brominated acid and the resulting ester then converted to the diacid ester of glycerol and the two brominated acids, as represented by the Equations 14 and 15. In RCOOCH: ether RCOOCH + 1101 —-—> 1 O +011: the conversion to the ester of glycerol, the re action may be su?iciently vigorous to cause at least a portion of the 41-, ?-diacid glyceride to be converted to the 04-, u-diacid glyceride. 10 RCOOCH: R'COC1+ HOCH + quinoline —-—+ 3000013, R000 3+ 01- Q (11) noon, Roooorn RCOOCH: R'COC1+ 110002;}: + quinoline ---> ‘ HO H: R'COO IH + quinolinc.HCl (l4) <3 —-<»—@H, 120000111 RG00 H + quinoline-HCI (12) R’OOOOH: If it is desired to prepare a triacid ester of 30 glycerol in which each of the hydroxyl groups of the glycerol are replaced by a different acid radical, the unsaturated acids are ?rst bromi nated to protect the unsaturated bonds. The 35 brominated acids are then converted to acid chlorides. It is apparent that if one of the hy droxyl groups is to be replaced by a saturated acid, the acid need not be brominated before converting it into the acid chloride. The acid 40 chlorides may RCOOCH, ether R’COO$H + H01 ——-> Owe-CH be represented by RCQCL, R’COCL and R"COCL. _ In the preparation of the glycerol ester, a monoacid ester is ?rst prepared by reacting the brominated acid chloride with acetoneglycerol in 45 the presence of quinoline. The ester of the brominated acid and acetoneglycerol condensa tion product is then converted to the monoacid ester of the brominated acid and glycerol. These reactions are represented by Equations 2 and 3. 50 The monoacid ester is then reacted with tri phenylmethyl chloride to protect one of the hy droxyl groups of the glycerol part of the mono acid ester, as illustrated by the following equa tion: 55 RCOOE‘JH; H0511: a'oooon + 0-0-01 (1s) The diacid ester is then reacted with the acid chloride of the third acid to form a triacid ester ‘of glycerol in which each of the hydroxyl groups of the glycerol molecule are replaced by different acid radicals. This reaction may be represented RCOOCH: by the following equation: I Q I -c1 + Boon + pyridine _-, HOCH: RCOOCH, R”COCl + R’COOCH + quinoline -——-§ HOCH: RCOOCH; R'COO H + quinoline.HC1 RC 0 0 OH: HO CH + pyridine.HCl (13) (16) R"COOCHI The puri?cation of the various products and the conversion of the esters of the acids and the glycerol derivatives into the esters of the acids and glycerol are carried out in the same manner as described hereinbefore with respect to the preparation of monoacid, diacid, and triacld 75 esters of glycerol. 2,408,905 14 be dried and cooled and the mixture allowed to crystallize. The ester of the sugar and the bro mine addition product of the acid, if an unsat urated acid is employed, ‘or the ester of the sugar and the saturated acid may be liberated from the condensation product, if a derivative of the sugar has been employed, in a manner similar to that described above with respect to the prepara tion of'esters of glycerol. If a bromine addition product was employed as the starting acid radical, the esters may be debrominated to reestablish the unsaturated bonds by the use of, for example, alcohol, as described above, to form the ester of Diacid esters of ethylene glycol and diethylene glycol may be prepared in a similar manner. For example, the glycol and quinoline may be dissolved in chloroform and the acid chloride added to the solution in small proportions. The reaction mixture is cooled continuously and agi tated until all of the acid chloride has been added. The reagents are employed in the ratio of one part of the glycol to two parts of the acid chlo ride to two parts of quinoline or pyridine. As pointed out in connection with the preparation of glycerides, we prefer to employ slightly more than two parts of acid chloride and the nitrog enous base, such as quinoline or pyridine, to in the sugar and the unsaturated acid. ' It is apparent that the method of the present sure a complete esterification of the hydroxyl 15 invention permits of the preparation of esters of groups of the glycol and to insure a complete removal of the hydrogen chloride from the re polyhydroxy compounds and unsaturated acids action mixture. The mass is then allowed to with a minimum of impurities since the unsat~ stand for about 4.8 hours at about room tempera urated bonds of the acids are protected from poly ture. 20 meriZation, oxidation, and other types of reac» The esters may then be taken up in cold ether tions during the preparation of the esters. After and washed several times consecutively with the esters of the polyhydroxy compounds and the cold dilute sulphuric acid, saturated sodium bi bromine addition product of the acid have been carbonate solution and water. The ether solu formed, the unsaturated bonds in the acid rad tion may then be dried over anhydrous sodium ical may be reestablished or restored as the final sulphate and cooled to permit crystallization of step in the preparation of the esters. When the the esters. debromination is carried out in a neutral alco If the acid employed in forming the diacid holic solution, there is no evidence of interesteri esters is an unsaturated acid, it is obvious that ?cation. However, when hydrochloric acid or the unsaturated bonds are ?rst protected by 30 free hydrogen chloride is present, small amounts bromination. The acid chloride is then formed, of esters, such as ethyl linoleate, may be formed. which is employed in the reaction with the ethyl Solvents other than alcohol which are satisfac ene glycol. If a saturated acid is to be employed tory for the purposes of this invention include in the reaction with the glycol, the acid chloride benzene, toluene and xylene. of the acid is ?rst formed and the acid chloride O1) We have described the use of bromine in con reacted with the glycol. If the bromine addi verting the unsaturated acids to saturated acids, tion product of an unsaturated acid has been however, it is apparent that other substances may used, the crystallized ester of ethylene glycol be employed. For example, iodine may be em and the bromine addition product of the acid is ployed, but the reaction is not as practical as that then debrominated by treatment with ?nely 40 which occurs when bromine is employed. The granulated zinc and alcohol to form the esters various intermediate products, such as the halo of ethylene glycol and the unsaturated acids. genated acids, and esters, are not as readily sep Esters of other polyhydroxy compounds may arated from the reaction mixtures by crystal also be prepared in accordance with the present lization as the products prepared by the use of invention. An example of a further class of poly bromine. hydroxy compounds is the sugars. Esters of The use of chlorine also is not as practical as monosaccharides, for example, galactose, glucose, the use of bromine. When chlorine is employed in fructose and mannose, and disaccharides, for ex preparing the saturated acids, there is a tendency ample, sucrose, maltose, and lactose, may be pre and some danger that the chlorine will replace pared in a manner similar to that described above. 50 some of the hydrogen atoms along the carbon The sugar or sugar derivative is mixed with quin chain. If such substitution or replacement occurs, oline or pyridine in a suitable solvent and the acid there is a tendency for hydrogen and chlorine chloride then added. It is obvious that the molec atoms on adjacent carbon atoms to split out to ular proportions of pyridine and the acid chloride form hydrogen chloride and produce an unsat with respect to the sugar must be in an appropriate urated bond where there had been previously a relation to e?ect the desired esteri?cation of the saturated bond. Furthermore, if the replacement sugar. Certain of the hydroxyl groups of the or substitution occurs at adjacent carbon atoms, sugar may be protected or removed temporarily and if the substituted chlorine remains linked by reaction with a ketonic compound, for ex to the adjacent carbon atoms throughout the ample, acetone or benzaldehyde. For example, various reactions, the ?nal reestablishment of two adjacent hydroxyl groups of the glucose may the unsaturated bonds in the ?nal product by be protected by reaction with acetone in a man removal of the chlorine will result in the estab ner similar to the reaction between glycerol and lishment of new unsaturated bonds in the acid acetone as set forth in Equation 1. Certain of the radical portion’ of the ester. hydroxyl groups may be protected by reaction In the preparation of various esters, it is not with triphenylmethylchloride in a manner similar necessary that the acid chlorides be employed. to that employed in the preparation of diacid For example, triacid glycerides and diacid glycols may be prepared by reaction of glycerol or glycol glycerides. The reaction mass formed by reaction of the with the bromine addition product of the unsat sugar derivative and the acid chloride of the bro 70 urated acids. mine addition product is then allowed to stand for We claim: n .. one or two days after which the mass is taken up in cold ether and washed consecutively with 1. The method of preparing esters of polyhy droxy compounds and unsaturated higher fatty acids which comprises saturating the unsatu cold sulphuric acid, saturated sodium bicarbonate solution and water. The ether solution may then 75 rated bonds of an unsaturated higher fatty acid 2,408,905 15 16 ' by halogenation to form a saturated higher fatty rated bonds of unsaturated higher fatty acid acid, converting the acid so saturated into an by halogenation to form a saturated acid, con verting the acid so saturated into an acid chlo acid chloride, reacting the acyl derivative with at least one hydroxyl group of a polyhydroxy compound to form an ester and thereafter de ride, reacting the acyl derivative with at least halogenating the acid radical portion of the ester in a mutual solvent to form an ester and there to reestablish the unsaturated bonds. after dehalogenating the acid radical portion of the ester to reestablish the unsaturated bonds. 6. The method of preparing esters of polyhy 2, The method of preparing esters of polyhy droxy compounds and aliphatic unsaturated one hydroxyl group of a, polyhydroxy compound higher fatty acids which comprises reacting the 10 droxy compounds and unsaturated higher fatty acid chloride of a bromine addition product of acids, which comprises halogenating the unsat an aliphatic unsaturated higher fatty acid with at least one hydroxyl group of a polyhydroxy compound to form an ester, and thereafter de urated bonds of an unsaturated higher fatty acid, converting the acid so saturated into an acid chloride, reacting the acyl derivative with brominating the ester. 15 a derivative of a polyhydroxy compound having 3. The method of preparing esters of glycerol at least one reactable hydroxyl group and at least and aliphatic unsaturated higher fatty acids one unesteri?able group replacing at least a part which comprises halogenating the unsaturated of a hydroxyl group to esterify the reactable bonds of an aliphatic unsaturated higher fatty hydroxyl group, hydrolyzing the reaction prod acid, converting the acid so saturated into an 20 not to reestablish all of the hydroxyl groups in the polyhydroxy compound portion of the prod acid chloride, reacting the acid chloride with at least one hydroxyl group of the glycerol to form an ester, and thereafter dehalogenating the acid radical portion of the glycerol ester to re establish the unsaturated bonds. 25 4. The method of preparing monoacid esters uct except the esteri?ed group or groups and dehalogenating the acid radical portion of the reaction product to reestablish the unsaturated bonds. 7. The method according to claim 4 in which of polyhydroxy compounds and aliphatic unsat the derivative of the polyhydroxy compound hav urated higher fatty acids which comprises re ing one reactable hydroxyl group is acetoneglyc acting the acid chloride of a, bromine addition erol. product of an aliphatic unsaturated higher fatty 30 8. The method of preparing triacid esters of acid with a derivative of a polyhydroxy com polyhydroxy compounds and aliphatic unsatu pound having only one reactable hydroxyl group rated higher fatty acids which comprises react and at least one unesteri?able group replacing ing the acid chloride of a bromine addition prod at least a part of a hydroxyl group to esterify uct of an unsaturated higher fatty acid with a the reactable hydroxyl group, hydrolyzing the 35 derivative of a polyhydroxy compound having reaction product to reestablish all of the hy three reactable hydroxyl groups to esterify said droxyl groups in the polyhydroxy compound por three hydroxyl groups and then debrominating tion of the product except the esteri?ed group, the resulting ester. and debrominating the resulting product. 9. The method according to claim 8 in which 5. The method of preparing esters of polyhy 40 the polyhydroxy compound is glycerol. droxy compounds and unsaturated higher fatty HOWARD C. BLACK. acids, which comprises saturating the unsatu CHARLES A, OVERLEY.