US2893990A - Process for producing sugar esters - Google Patents

Description

Uite

PROCESS FOR PRODUCING SUGAR ESTERS Henry B. Hass, Summit, N.J., and Foster D. Snell, New

York, William C. Yorlr, Westbury, and Lloyd I. Osipow, Brooklyn, N.Y., assignors to Sugar Research Foundation, Inc., New York, N.Y., a corporation of New York No Drawing. Application December 12, 1955 Serial No. 552,281

18 Claims. (Cl. 260-234) them. More particularly, the present invention relates to a novel process for producing esters of sucrose or raflinose and fatty acids having from about 6 to 30 carbon atoms and to the esters obtained thereby.

It is an additional object of the present invention to provide a novel and efiicient process for economically producing fatty-acid esters of sucrose or ratfinose in excellent yields.

It is also an object of the present invention to provide a novel and efficient process for producing monoor difatty-acid esters of sucrose or raffinose in excellent yields and in relatively pure form substantially free from contamination of other esters.

Additional objects will be apparent to those skilled in the art from reading the specification which follows.

In recent years much research has been done in the field of synthetic surface-active agents, particularly in the field of synthetic detergents. In spite of this great volume of research, there are few non-ionic surface-active agents commercially available which are solids. Those which are available are comparatively expensive and possess limited detergent properties.

The non-ionic surface-active agents have certain desirable properties for use in the detergent field. For example, they are compatible with both cationic and anionic surface-active agents. They can tolerate the calcium and magnesium ions present in hard waters to a greater extent than can the anionic surface-active agents, they are less dependent upon the anhydrides of the phos phates than are the anionic surface-active agents in providing good detergent properties and, also, they tend to be less tenaciously adsorbed on the substrate than either anionic or cationic surface-active agents.

Surface-active agents are desirably solids, rather than liquids, particularly in the case of detergents sold to the housewife, for they can be readily mixed with the inorganic salts and other ingredients employed in detergent compositions to produce free-flowing powders and spraydried beads. Surface-active agents having these propperties permit the production of detergent products at a lower cost per pound and also the final product may be conveniently packaged and dispensed.

'I he fatty-acid monoor di-esters of sucrose or raffinose, which are produced in accordance with the process of the present invention, suitably combine all of the desirable properties described in the foregoing discussion and they may be manufactured efficiently and inexpensively in accordance with the novel process of the present invention.

Additionally, the fatty-acid monoand di-esters of sucrose of the present invention are suitable for use in foods for human and animal consumption. This is an important advantage of these esters since many of the ates Patent surface-active agents of the prior art have been subjected to criticism by governmental administrative agencies because of suspected toxicity or because of suspected side effects or irritant qualities. The fatty-acid mono-esters of sucrose produced according to the process of the present invention are completely safe and are more watersoluble than the fatty-acid mono-esters of glycerol, which have been. the surface-active agents of choice of the prior art for products intended for human consumption. The esters of sucrose hydrolyze into their fatty-acid and sucrose components in the digestive'tract subsequent to ingestion and are well tolerated by the human body without adverse side effects. The sucrose di-esters of a fatty acid are less soluble in water and furnish a type of emulsifier not previously available.

Because of the beneficial properties of the fatty-acid monoand di-esters of sucrose of the present invention, they have widespread application in the surface-active agent field. For example, because of their high degree of palatability, edibility, digestibility and their high food value, these esters may be employed widely in food products. They may be employed for emulsifying salad dressings and other food products, etc. which are not acidic. By employing them it is possible to emulsify chocolate without first removing its delicious cocoa butter, such as is the present day practice. When they are employed in the diet of people who have difficulty in digesting fat, in particular aged people or very young babies, it appears that it will aid in the absorption of fat from the digestive tract.

The monofatty-acid esters of the invention may be used for various detergent purposes. They are substantially non-irritating to the skin and mucous membranes and are therefore Well tolerated by the human or animal body. They may be formulated into a detergent bar for toilet or laundry use, which may optionally contain a germicidal or bactericstatic agent. They may be incorporated into shampoos which will not produce any stinging or irritation of the eyes of the user. Shaving creams, cosmetics and detergent bars employing these esters are completely free from irritation to the skin and mucous membranes. Fruits and vegetables may be thoroughly cleaned with these esters of the invention without spoiling their flavor and any residues left on are harmless. When these edible, palatable detergents are employed for washing purposes they are relatively unaffected by the hardness of the water. When used for washing dishes, it is not necessary to wipe them dry since, should any small amount of detergent remain on the dishes when dry, it will create no adverse response on the part of the user.

The mono and di-esters of the present invention may also be employed in preparing pharmaceutical products, such as emulsions, toothpastes, etc. When employed in toothpastes they impart no unpleasant flavor or odor to the product such as do present day soaps and some synthetic detergents. Consequently, toothpastes containing these mono-esters of the invention are not only ideally suited for their purpose, but they have a high degree of customer acceptability because of their freedom from unpleasant odor or taste.

The monoand di-esters of the invention may be employed in producing poultry, cattle and swine rations to improve the digestibility of such rations.

The di-esters of sucrose are useful as demulsifiers, emulsifying agents, antispattering agents for frying oils and fats, bread softeners and lubricants.

The esters of the present invention maybe employed for secondary oil for petroleum recovery whereby aqueous whereby solutions of these esters are used to displace residual oil from the underground rock and thereby permit more efficient recovery of petroleum from the ground,

The present invention comprises fatty-acid esters, and particularly the monoand di-esters, of sucrose or raflinose, produced in accordance with the novel process of the present invention, and in which the fatty-acid moiety of the esters contains from about 8 to 30' carbon atoms, inclusive, and more desirably from about 12 to-22 carhon atoms, inclusive. As a particular subclass for use as wetting agents the dieesters having 6 to 12 carbon atoms in the fatty-acid moiety are suitable. Among the fatty acids which may constitute the fatty-acid moiety of the men-esters of sucrose or rafhnose are the saturated fatty acids, including: lauric, myristic,-palmitic, stearic acids, etc., and the unsaturated fatty acids and preferably mono-unsaturated fatty acids, including: A -dodecyh eriic', palmitoleic, 'oleic, ricinoleie acids, etc., or mixtures of these acids.

For the purpose of the present invention, it is intended to include within the scope of the fatty-acid. moiety those higher moleculaf-weight carboxylic acids derived from naturally-occurring materials, such as the so-called rosin acids obtained from rosin or from tall oil. The principal component of rosin is abietic acid and its anhydride, which constitute about 80%90% of the rosin and nearly 50% of tall oil consists of resin acids of analogous structure.

Preferably, however, the products of the invention are fattyaacid monoand di-esters, often of mixed fatty acids, which are produced in accordance with the process of the present invention having mixed fatty acids obtained from naturally-occurring glyceridic oils and fats. These glyceridic fats and oils include: tallow, coconut oil, spermwhale oil, lard, lard oil, cocoa butter, palm oil, castor oil, corn oil, olive oil, soya bean oil, herring oil, menhaden oil, etc. The resulting mixed monoand di-esters contain the fatty acids initially present in the fats and oils in relatively the same proportions in which they occurred in the original fats and oils and the final product appears to have superior properties over those esters containing but a single fatty acid.

7 The present invention further comprises a novel process for producing the fatty-acid esters of sucrose or rafiinose. The process comprises reacting a non-sucrose or nonratfinose ester of a fatty acid with sucrose or raflinose. The reaction is desirably conducted in an aromatic, aliphatic, alicyclic or heterocyclic solvent having an amide group or constituent or a solvent which is a heterocyclic of aliphatic tertiary amine, or a dialkylsulfoxide, although in inany cases the use of a solvent may be dispensed with. The reaction mixture shall contain an alkaline cactalyst. Preferably, substantially anhydrous conditions are employed as e"en small amounts of moisture may retard the rate of reaction. The reaction is produced by heating the reaction mixture at a temperature of from about 20 C. up to about 180 C. The optimum temperature range is from about 60 to 120 C. At the lower temperatures the reaction products are less colored. The reaction time required is usually between about 30 minutes to 24 hours, depending somewhat upon the temperature of the reaction mixture and the alkalinity of the catalyst, although 2 to hours is generally preferred.

The non-sucrose and non-rafiinose esters of the fatty acids employed as starting materials and as a source of fatty acids may be simple esters of a mono-hydric alcohol, such as methyl palmitate, methyl stearate, ethyl laurate, methyl abietate, ethyl abietate, etc., or they may be esters of a polyhydroxy alcohol, or polyol, where the hydroxyl groups of the alcohol are on adjacent carbon atoms, such as thediand tri-esters of glycerol.

We prefer to employ as thenon-sucrose ornon rathnose starting ester, an ester of a fatty acid and a readily volatile alcohol, such as the lower monohydric alcohols, methanol or ethanol. The. volatile alcohol is preferably stripped from the reaction mixture by distillation, desi'rably under reduced pressure, as it is liberated during theformation of the sucrose or raflinose ester. This a l 2,893,990 h permits a more rapid reaction and provides higher yields of the sucrose or rafiinose esters, and'accomplishes a separation of the volatile alcohol from the reaction solvent and the reaction products. Where it is desired to employ mixed fatty acids, such as mixtures which occur in mixed, naturally-occurring glyceridic esters, we prefer to first convert the glyceridic esters to mixed esters of a volatile alcohol by reacting the glyceridic esters with the. alcohol to produce an ester interchange. As an alternative to yacuum' distillation, the volatile alcohol may be removed from the reaction mixture by heating the mixture at substantially atmospheric pressure to a temperature of about the boiling point of the alcohol and sweeping the system withan inert gas, such as air or nitrogen, which will not react with the reactants or the reaction products to any substantial degree.

Among the suitable solvents which may be employed for the reaction are such tertiary amines as: trimethylamine, triethylamine, N-methylmorpholine, pyridine, quinoline, pyrazine, methylpyrazine, N,N-dimethylpiperazine, etc., such amides as: formamide, N,N-dimethylformamide, 2-pyrrolidone, N-methyl-Z-pyrrolidorie, etc. Dimethylsulfoxide is an excellent solvent. Other solvents may be suitably employed. The solvent material employed may contain other additional polar groups in the molecule although such groups preferably exclude mercapto, hydroxyl, ester, primary and secondary amino groups. Desirably the amine or amide shall have not more than 6 carbon atoms for each nitrogen atom present in the molecule and the total number of carbon atoms shall not exceed 12. The preferred solvents employed to date are N,N-dimethylformamide and dimethylsulfoxide. We prefer to employ av solvent which is less volatile than the alcohol, of thenon-sucrose or non-raflinose ester starting material.

Among the alkalinecatalysts which may be employed are several types of metals, hydroxides, inorganic salts and organic compounds, including alkali-metal hydroxides, such as potassium, sodium and lithium hydroxides, salts .of an alkali-metal and a weak acid, such as sodium carbonate, potassium carbonate, etc.; or such alkaline salts as trisodium phosphate; or alkali-metal alcoholates,

- such as sodium methoxide, potassium ethoxide, sodium ethoxide; or organic bases, such as the quaternary ammonium bases, including the mixed alkyl-dimethyl-benzyl ammonium hydroxides, the-alkyl-trimethyl ammonium hydroxides and tetra-alkyl quaternary ammonium hydroxides, such as. tetra-methyl ammonium hydroxide, cetyl-dimethyl-benzyl ammonium hydroxide, etc.; or the alkali-metal sucrates or raflinates, such as sodium sucrate, sodium raffinate, etc. Additionally metals, such as tin-and zinc maybe employed. Alkaline salts and alkali-metal carbonates, and particularly potassium carbonate, are the preferred catalysts.

Generally speaking, the alkaline catalysts which are satisfactory are those which are soluble in the solvents employed and which, when added in a 1% w./v. concentration in a 0.5% w./v. phenolphthalein solution in a solvent containing equal parts by volume of boiled N,N- dimethylformamide and carbon dioxide-free water, gives the. characteristicalkaline phenolphthalein magenta color. The phenolphthalein solution is prepared by first boiling the N,N-dimethylformamide for 15 minutes to remove volatile amines. One gram of phenolphthalein is dissolved in ml. of the boiled N,N-dimethylformarn ide and 100 ml. of carbon dioxide-freewater is added. When 0.1 gram of the alkaline catalyst is added to 10 ml. of the, resulting. phenolphthalein indicator solution, it should give the well knownpinkish-purple or magenta color of alkaline pheno-lphthalein solutions.

Where a reaction solvent is employed which tendsto evaporate at the temperatureof the reaction, or where the volatile alcohol is-removecl as it forms, it is advisable to conduct the reaction in a closed pressure vessel.

m g t m tfl'tant ch raq ri tiq he p cess o an alkoxyl anion. .hydrogen cation generating another sucrate or raifinate tained.

The process of the present invention will provide mono-,, dior other multiple-substituted esters of sucrose 'or raifinose, depending upon the molar ratio of sucrose or raffinose to non-sucroseor non-rafiinose ester present. Thus if thereaction mixture contains a ratio of three or -more 1110168 Of sucrose to 0116 111016 Of non-sucrose ester,

and the alcohol is distilled from the mixture as it forms, the product obtained issubstantially a mono-ester. If one mole of sucrose is employed with two moles ,of a fattyacid ester of a volatile alcohol, the product is essentially a di-ester of sucrose. The .largerthe molar proportion of non-sucrose or non-raflinose ester to sucrose or rafiinose, respectively, the higher will be thedegree of esterification of the sucrose or ratfinose. By using largeenough ratios of non-sucrose ester, it is possible to provide esters ofsucrose in which several hydroxyls are esterified. It is also possible to first prepare a poly-ester of sucrose and react this with-an excess of sucrose equivalent'to a three to one ratio in one of the aforementioned solvents and in the presence of one of the aforementioned alkaline catalysts, tofiorm substantially pure mono-ester. For practical purposes we prefer to employ a 152 to 1:3 ratio of "non-sucrose ester to sucrose.

Based upon evidence available to date, it appears that the mechanism of the reaction which comprises the process of the present invention is based upon initial conversion of the sucrose or raflinose .tothe sucrate or raffinate anions, respectively. This conversion :can be accomplished in :therea'ctionmixture rbythe alkaline catalyst. Thealkaline'cataiyst'appears to combine one of the hydroxyl hydrogen ions of the .sucroseorrafi'inose with :an'

alkalineanion to form'the sucrate or rafiinate anions,

respectively. The sucrate or raffinate anion thenappears to react with the ester of the fatty acid to form the sucrose or rafiinose mono-fatty-acid esters of the invention and The alkoxyl anion then withdraws a anion which continues the chain of reaction. Someof the supply of sucrate or rafiinate anion is depleted during the process. Support for this suggested mechanism is fiound in the fact that the alkali-metal-sucrates are satisfactory catalysts for the process.

As employed in this specification, the terms sucrate and raifinate refer to the anions formedupon replacing one of the hydrogen .ions on oneofthe hydroxyl groups of su- 'crose or raflinose, respectively.

by weight, of alkaline catalyst. This product is suitable for numerous applications, including detergency, without further purification. In some cases it is desirable to recover the sucrose to .bexrecycled in the process. This maybe accomplished by dissolving the dry residue, which remains after distillation, .in three to four times its Weight of water, followed by the addition of about 5% of sodium chloride based on the quantity of Water. This mixture may be heated to about 80*90'C. and maintained at this temperature until thesucrose mono-ester has separated into a separate layer. The curdlayerof sucrose mono-ester is separated and dried. This curd usually contains about 50 to 60% solids of which about 80 to '85%-is alcohol-soluble. The remainder is sucrose and sodium chloride. The aqueous layer which now contains most of the unreacted sucrose may be evaporated ess of the invention.

' .invention will hereinafter be described.

Complete removal 10f the sucrose and sodium chloride may be efliciently accomplished by partitioning the solids obtained after distillation of the solvent between an aqueous 5% sodium chloride solution and nrbutanol. The butanol layer is separated and the butanol distilled 011?. The resulting product isabout sucrosemonoester. The remainder is soap and poly-esters of sucrose. This 90% pure product can berecrystallized from acetone to provide pure sucrose mono-ester.

Where a sucrose di-ester is produced, the residue which remains after simpledistillation of the reaction solvent contains more than 90% pure sucrose di-ester. Further purification is not usually required for most commercial applications.

Another method of purifying-sucrose mono-esters obtained by the hereinabove describedreaction, where one of the amide or tertiary amine solvents are employed, will now be described. While theprecise procedure will vary in accordance with the specific solvent or the nature of the reactants employed, in general, the process comprises distilling off a substantialquantity of the solvent, such as A to /1 of the volume employed, and preferably /2 of the volume employed. The residue is then cooled, desirably to about 20 to 30' C. As a result of cooling, the unreacted esters of 'the fatty acids used as a starting material separate from the residue. This is true of both the unreacted triand di-fatty-acid esters of glycerol and fatty-acid esters of themono-hydroxy alcohols, whichever is employed. The resulting monofatty acid esters of sucrose, and part of any mono-esters degree of purification obtained is adequate for many commercial applications of the mono-esters of sucrose. However, a further and high degree of purification may be achieved by extracting the resulting solution with an aliphatic hydrocarbon solvent, preferably a lower aliphatic saturatedhydrocarbon, such as hexane or pentane. This treatment extracts the last traces of unreacted non-saccharide esters of fatty acids from the solution. This'remaining solution is further distilled toa low volume and then diluted with several volumes of a polar solvent, such as acetone or butanol, to precipitate the unreacted sucrose. The sucrose is filtered to produce a clear'solution of the mono-ester of sucrose. This is distilled and the residue obtained represents a commercially pure mono-ester .of sucrose. Best results with this purification process are obtained when formamide, N-methyl-Z-pyrrolidone or N,N-dimethylformarnide, and particularlythe last, is em- .ployed as the reaction solvent.

In order more clearly to disclose the nature of the present invention, specific examples illustrating the present It should .be understood, however, that this is done solely by .wayof example and is intended neither to delineate the scope of the invention nor limit the ambit of the appended claims. Where conversion yields-.are reported inthe examples .which follow, .it is intended to refer ,to the ratio of sucrose converted to ester compared with the sucrosenot recovered from the reaction mixture in a form suitable for re- ,cycling. Parts are expressed in termssofparts-by weight.

Example I A solution was prepared'by. mixing,.accompanied.by gentle heating, grams (0.293 mole) of sucrose with 400 ml. of N,N-dimethylformamide. To theresulting solution was added 173 grams (0.195 mole) or tristearin and 1.0 gram of sodium methoxide. Themixture was heated for 3 hours in a closed container at about to C. About A. of the dimethylformamide was then distilled from the reaction mixture. .Theresidue .Was

. cooled to between about 20-and 30 C. and unreacted tristearin and resulting distearin separated from the vclimethylformamide and were removed by filtration. The resulting solution was extracted withseveral .timesits volume of normal hexane and then distilled to a thick solution was equivalent to a yield of 29%, and 34% of the sucrose starting material was recovered unchanged.

Example II A solution was prepared by dissolving about 100 grams (0.293 mole) of sucrose in 440 ml. of N,N-dimethylformamide and with this was mixed 94 grams (0.147 mole) of distearin dissolved in 300 ml. of N,N-dimethylformamide. The resulting mixture was placed in a pressure bomb containing about 3 grams of sodium methoxide and the bomb was heated for about 15 hours at about 160 C. About /2 of the solvent (dimethylformamide) was removed by vacuum distillation. The remaining solution was cooled to nearly room temperature, after which unreacted distearin was precipitated. The precipitate was removed by filtration and the filtrate was extracted three times with equal volumes of hexane. The resulting dimethylformamide solution was further distilled in vacuo to a thick syrup, which was precipitated with acetone. The acetone solution was evaporated, producing a residue which was composed of 22 grams (0.036 mole) of relatively pure sucrose mono-stearate, having a melting point of about 5253 C.; M1 +33.2, for an absolute yield of 24.6% based upon the amount of distearin employed in the reaction. The unreacted sucrose obtained above was filtered and dried to be used in subsequent processes. Pure sucrose monostearate was found to have a melting point of 5253 C.

and lul +39.35.

Example III A solution was prepared by suspending about 100 grams (0.293 mole) of sucrose in 600 ml. of pyridine. With this suspension was mixed about 173 grams (0.195 mole) of tristearin dissolved in 300 ml. of pyridine. About grams of sodium methoxide were added to the mixture after which the mixture was heated in a closed pressure bomb for 15 hours at a temperature of approximately 150 C. A major fraction of the pyridine was distilled under vacuum from the reaction mixture and the residue was then dissolved in a minimum quantity of dimethylformamide. When the resulting solution was cooled to below room temperature, it was filtered and the filtrate extracted twice with equal volumes of hexane, and the filtrate diluted with 5 times its volume of acetone. Unreacted sucrose then precipitated from the filtrate and was recovered by filtration. The acetone filtrate was then evaporated to dryness to produce 35 grams (0.058 mole) of sucrose mono-stearate which was equivalent to a yield of 29.5% based upon the amount of tristearin employed.

Example IV A solution was prepared by dissolving about 100 grams (0.293 mole) of sucrose in 500 ml. of N,N-di- 'methylforrnamide. To the resulting solution was added about 170 grams (0.195 mole) of inedible-grade tallow, a

'moved. The remaining dimethylformamide solution was 'purified as described in Example II. sucrose mono-tallowate which was recovered indicated a conversion yield of about 25 The amount of .formamide. grams (0.20 mole) of methyl laurate dissolved in 400 Example V V The procedure of Example IV was repeated except that the tallow fat dissolved in pyridine was replaced with a solution of about 116 grams (0.175 mole) of coconut oil dissolved in 400 ml. of N,N-dimethylformamide. (The coconut oil contained a fatty acid-content of about 45% lauric, 18% myristic, 10% palmitic and 8% oleic acids. The remainder of the fatty acids content was made up of small percentages of other saturated and unsaturated acids.) About 35 grams (0.066 mole) of sucrose mono-cocoate were obtained for a yield of about 37.5% based upon the amount of coconut oil employed.

Example VI A solution was prepared by dissolving about 70 grams (0.208 mole) of sucrose in 400 ml. of N,N-dimethylformamide. With the resulting solution was mixed 92 grams (0.14 mole) of tristearin dissolved in 400 ml. of dimethylformamide. The mixture was placed in a pressure bomb along with 3 grams of trisodium phosphate. The bomb was heated for about 8 hours at a temperature of C. One-half of the dimethylformamide was removed by distillation and the resulting sucrose monostearate was recovered as in Example II. The quantity of recovered substantially-pure sucrose mono-stearate indicated a conversion yield of about 29%.

Example VII A solution was prepared by dissolving about 100 grams (0.293 mole) of sucrose in 500 ml. of N,N-dimethyl- With this solution was mixed about 62 ml. of dimethylformamide. About 2 grams of sodium methoxide were added to the resulting mixture and the mixture placed in a pressure bomb where it was heated .tilled to give a residue which, when recrystallized from acetone, produced 20 grams of sucrose mono-laurate (M.P. 72-80 C.; [a] =+52.0) to provide a conversion yield of about 50%. Pure sucrose mono-laurate was found to have a melting point of 90-91 C. and [a] =+42.5.

Example VIII The procedure of Example VII was repeated replacing the methyl laurate with about 87 grams (0.294 mole) of methyl oleate. As a result of this process there was produced sucrose mono-oleate in an amount equivalent to a yield of 17%.

Example IX A 200-gram (0.397 mole) portion of previously desiccated retfinose was dissolved in 800 ml. of dry N,N- dimethylformamide. To this was added grams (0.263 mole) of coconut oil. The resulting solution was heated to 90 C. and kept at this temperature for 12 hours with constant stirring. During this time four l-gram portions of sodium methoxide catalyst were added. At the completion of the reaction, the solution was extracted four times with equal volumes of hexane. The resulting dimethylformamide solution was distilled 'under a vacuum of 1.0 mm. mercury until a thick syrup was obtained. This syrup was diluted with seven volumes of acetone and the resulting suspension was mixed thoroughly. The precipitated unreacted raflinose was times with equal volumes of hexane. formamide solution was then distilled to /z of its volleached with the acetone solution for four hours. The

suspension was filtered and theinsoluble residue was extracted with n-butanol. The butanol extract was added to the acetone extract and the combined extracts were distilled to solidification. The resulting rafiinose cocoate was dried thoroughly to give 85 grams of product.

Example X A solution was prepared by dissolving about 100 grams (0.293 mole) of sucrose in 400 ml. of N,N-dimethylformamide. "mole) of methyl laurate and 2 grams of solid potassiu'm 'hydroxide. 100 C. in a covered beaker'for 12 hours.

To this was added 62.5 grams (0.293

The resulting mixture was heated to 90- After cooling, the dimethylformamide solution was extracted five The dimethyltune and precipitated with volumes of acetone. The sucrose which thenprecipitated was extracted withhbutanol. The butanol was added to the acetone-dirnethylformamide solution and the combined solvents were disstilled to a thick syrup. A further crop of sucrose was separated at this stage and the filtrate was dried to. give 259 grams (16.9% yield) of sucrose mono-laurate, [a] =+47.6.

Example XI A solution was prepared by dissolving about 100 grams (0.293 mole) of sucrose and 62.5 grams (0.293 mole) of methyl laurate in 400 ml. of N,N-dimethylformamide.

To this was added grams of cocoyl trimethyl am- -monium sucrate as a catalyst, which'had-been prepared by adding 4.4-grams of cocoyl trimethyl ammonium hydroxide to 5.7 grams of sucrose in 20 ml. of dimethylformamide and distilling off all solvents to produce'adry product. The resulting solution was heated at 90-100 C.

for 12 hours in an open beaker. After cooling, the dimethylformamide solution was extracted five times with equal volumes of hexane. The dimethylformamide solution was then distilled to /3 of its volume and precipitated with 5 volumes of acetone. The sucrose which precipitated was filtered and the acetone-dimethylfonnamide solution was distilled to dryness to yield 40 grams of sucrose mono-laurate.

In each of the foregoing examples the unreacted nonsaccharide fatty-acid esters employed as starting materials were almost Wholly recoveralble in a-form-suitable for recycling in the process or for other commercial uses.

Example XII Employing completely dry materials, about 387 grams of sucrose were dissolved in 1275 ml. of dimethylformamide by heating with vigorous agitation. 112.5 grams of methyl stearate and 7.5 grams of potassium carbonate were added to the solution. The resulting'reaction mixture was maintained at 90-95 C. at a pressure of 80 to 1-00 mm. of mercury. The methanol produced during the'course of a reaction was stripped from the system as it formed by means of a six-.platefraction-ating column. After 9 to 12 hours, part of the dimethylformamide was distilled and the residue was dried under vacuum. The

dry .residue was found to contain 53.9% sucrose, 37.9% sucrose monostearate, 1.6% sucrose distearate, 0.0% methyl stearate, 2.9% potassium stearate and 1.3% potassium carbonate.

Example XIII Sucrose monostearate was prepared using high concentrations of reactants in dimethylsulfoxide. The reaction mixture consisted of 150 grams of methyl stearate, 516

grams of sucrose, 350 milliliters of dimethylsulfoxideeand' 15 grams of potassium carbonate. After 7.5 hours at 90 C., 100 mm. mercury pressure, and-sweeping of the system with carbon dioxide-free dry air, the methyl stearate was completely converted to approximately equal parts by weight of sucrose monostearat'eand distearate.

potassium canbonate. stantially anhydrous. duced by subjecting the tallow employed in Example IV,

. amide.

methyl stearate. grams of methyl stearate, 172 grams of sucrose, 850 millifor momoester formation had reacted. After 2 hours,

percent of the methyl stearate and 78 percent ofthe theoretical sugar had reacted to form sucrose monostearate.

Example XV This example describes the preparation of sucrose monotallowate. The reaction mixture consisted of about 112.5 grams of methyl tallowate, 387 :grams of sucrose,

1275 milliliters of dimethylformamide and 7 .5 grams of The reaction mixture was sub The methyl tallowate was proabove, to ester exchange with methyl alcohol, in accord- :ance with well-known procedures and removing the glyc- 'ero1 which formed. After heating the reaction mixture for 12 hours at to C., mm. mercury pressure, without sweeping the system with air, the distribution of tallowate was as follows: 5.3% as unreacted methyl tallowate, 2.4% as soap, 66.4% as sucrose monotallowate and 25.9% as sucrose di-tallowate.

At the completion of the reaction, the solution was distilled to remove about 90 percent of the dimethylform- Then 500 milliliters of n-butanol and 500 milliliters of water were added to the resulting paste. The

' mixture was heated with stirring until solution of the solids in the two liquid phases was complete. The layers were separated while hot and the butanol layer was Washed once with an additional 500 milliliters of cold water. Analysis of the combined water layers showed that 96.5

' percent of the sugar esters were recovered in the butanol layer.

Example XVI Sucrose distearate was prepared by heating a solution consisting of grams of methyl stearate, 82 grams of sucrose, 15 grams of potassium carbonate and one liter of dimethylformamide. The reaction was carried out at 90 C., 100 mm. mercury pressure and carbon dioxidefree dry air was bubbled through the solution. After 12 hours, 97 percent of the methyl stearate had reacted to give a product containing, aside from catalyst, about95 percent sucrose distearate and the remainder methyl stearate and potassium stearate.

Example XVII Sucrose dicocoate was prepared using a 2 to 1 molar ratio of methyl cocoate to sucrose. The reaction mixture consisted of 230 grams of methyl cocoate, 172 grams of sucrose, 680 milliliters of dimethylformamide and 15 grams of potassium canbonate. The methyl cocoate was produced by reacting the coconut oil described in Example V above with methanol to produce ester exchange in accordance with well-known methods and the glycerol which formed removed. The reaction was heated to 90 C. at 100 mm. mercury pressure and carbon dioxide-free dry air was bubbled through the mixture. After 12 hours,

all but 4.5 percent of the methyl cocoate had reacted. Approximately 5 percent of the methyl cocoate was converted to soap. Thus, approximately 1.8 moles of cocoate was esterified per mole of sucrose to produce sucrose dicocoate.

' Example XVIII One mole of sucrose was reacted with four moles of The reaction mixture consisted of 600 liters of dimethylformamide and 5.0 grams of potassium carbonate. The reaction mixture was heated for 12 hours at 90 to 95 C. and 100 mm. mercury pressure, without air bubbling through the solution. Analytical data showed that 2.0 percent of the methyl stearate had been converted to soap and 14.6 percent of the methyl stearate was recovered unchanged. Thus 3.3 moles of methyl stearate per mole of sucrose had reacted to form sucrose poly-stearate.

Example XIX A. Employing completely dry materials, 129 grams of sucrose were dissolved in 425 ml. of dimethylformamide by heating with vigorous agitation. To this solution was added 37.5 grams of methyl stearate and 2.5 grams of potassium carbonate. The reaction mixture was maintained at 90 to 95 C. under 80 to 100 mm. mercury pressure. Dry, carbon dioxide-free air was bubbled through the solution at approximately 100 ml. per minute. A six-plate fractionating column was employed for stripping the methanol from the system. After 10 hours reaction time, the mixture was distilled to dryness. Analysis of this residue showed 76 grams of sucrose monostearate and 86 grams of sucrose.

B. A 100-gram portion of the residue from A above was added to 300 ml. of a 10 percent aqueous sodium chloride solution and 300 ml. of n-butanol. The mixture was warmed, while stirring, until the solids had dissolved completely. The two layers were separated and the hutanol layer was washed with two 150 ml. portions of a 10 percent aqueous sodium chloride solution. The butanol layer was distilled to dryness to give a solid residue containing 93 percent sucrose monostearate.

Example XX The process of Example XIX was repeated. The dry residue (170 grams) was dissolved in 680 ml. of water by heating. Then 68 grams of sodium chloride were added. The batch was aged overnight, and the curd which formed was separated by filtration and dried. The solid residue contanied 67 percent sucrose monostearate. The remainder was salt and sucrose.

Other glyceridic fats and oils and mono-hydric alcohol esters may be used in producing sucrose esters in accordance with the process of the present invention.

More specifically, in place of the tallow fat employed in Example IV hereinabove, equimolecular quantities of one or more of the following glyceridic fats or oils may be substituted: sperm-whale oil, lard, lard oil, peanut oil, cocoa butter, palm oil, castor oil, corn oil, olive oil, soya bean oil, herring oil, menhaden oil, etc. The resulting mixed fatty-acid esters of sucrose or rafiinose contain a fatt -acid content in relatively the same proportions in which they originally occurred in the initial oil.

Other alkaline catalysts may be employed in place of those employed in the examples described hereinabove. In particular, potassium methoxide, sodium ethoxide and other alkali-metal alcoholates may be satisfactorily employed, as wel las alkali-metal sucrates, such as potassium sucrate and alkali-metal hydroxides such as sodium hydroxide and lithium hydroxide.

In place of the solvents employed in the above examples, other solvents may be employed. For example, excellent results have been obtained in employing N-methyl-2- pyrrolidone or 2-methylpyrazine These solvents are particularly stable in the presence of highly basic catalysts. Other amines, such as trimethylamine, are satisfactory, although where the amine is low boiling, precautions must be taken to prevent loss of these materials when subjected to higher temperatures. The reaction system should be a closed one to prevent loss of the solvent. Preferably the solvent shall be less volatile than the alcohol of the non-sucrose ester starting material.

While the sucrose employed in the present process may take the form of the less pure materials which are available as by-products of sugar refining, etc., best results are obtained with the. relatively pure 'solid forms of sucrosewhich'are available in abundance at very low cost.

'As has been expressed hereinabove, the monoand di- 5 esters" of sucrose of the present invention possess excellent detergent, emulsifying, Wetting and dispersing properties and may be used for a wide variety of purposes. When compared with the non-ionic detergents of the prior art, they" demonstrate superior properties; The monoesters of sucrose of the invention have demonstrated excellent properties as a detergent for human cleanliness or for washing clothes, dishes, etc., and the process of employing these esters for cleansing purposes comprises one of the important features of the present invention. When used'for washing clothes, etc., the mono-esters of the invention may be used in the form of a built detergent composition, i.e., in admixture with detergent aids such as will synergize the detergent properties of the sucrose or raflinose esters of this invention. Examples of these synergizing aids are the molecularly dehydrated phosphates, the alkali-metal phosphates, alkali-metal silicates, borates, carbonates, sulfates, chlorides. Sodium carboxymethylcellulose is also a desirable component of such a detergent composition. Detergent compositions containing from 10 to 40% by weight of a mono-ester of sucrose or raffinose ester comprise an important part of our invention.

Exampels of heavy-duty detergent compositions containing sucrose monoesters according to our invention are as follows:

Parts by Weight Example Number 21 22 23 24 25 26 27 Sucrose mono-tallowate (Example IV) Sucrose mono-cocoate (Example V) Sucrose mono-cleats (Example II Sodium tripolyphosphate. Tetrasodium pyrophosphate Sodium silicate (NazO:

SiO2=1:3.2) Sodium silicate (NazO:

BiO2=1'2) Sodium carboxymethy cellulose Moisture Sodium dodecylbenzene sulfonate 10.0

The composition of the above examples may also contain one of the brighteners commonly employed in detergent compositions. Such a composition may be desirably employed in a 0.1% to 0.5% aqueous solution.

The novel detergent compositions of the invention are the subject matter of our copending application, Serial No. 714,490, filed February 11, 1958.

The novel esters of sucrose or rafiinosc and fatty acids produced in accordance with the invention may have admixed with them germicidal or bacteriostatic agents, particularly when the esters are employed in making detergent cakes for toilet use. Among the germicidal and bacteriostatic agents which may be employed are: hexa- '65 chlorophene and the quaternary ammonium salts, such as the alkyl-dimethyl-benzyl ammonium halides sold un der the trademarks Zephiran chloride, Roccal, Triton K-60 and Ammonyx, including cetyl-dimethyl-benzyl ammonium chloride and octylphenoxyethoxyethy1-di methyl-benzyl ammonium chloride (Hyamine).' Other quaternary ammonium salts, such as cetyl trimethylammonium chloride, etc., may be used. Where a quaternary ammonium base is employed as a catalyst in producing the mono-esters of the invention, it may be recovered with the reaction product and converted to the active quaternary ammonium salt by adding dilute mineral acid.

The terms and expressions which we have employed are used as terms of description and not of limitation, and we have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible Within the scope of the invention claimed.

What is claimed is:

l. A process for producing an ester of a fatty acid containing between about 6 and 30 carbon atoms and a saccharide selected from the group consisting of sucrose and raifinose, which comprises treating a member of the group consisting of sucrose and raifinose with an ester of a fatty acid containing between about 6 and 30 carbon atoms and a non-saccharide alcohol, in the presence of an alkaline catalyst, at a temperature in the range from between about 20 and 180 C., and in the presence of a solvent.

2. A process as defined by claim 1 wherein the saccharide is sucrose.

3. A process as defined by claim 1 wherein the saccharide is raifinose.

4. A process as defined by claim 1 wherein the fatty acid moiety is saturated.

5. A process as defined by claim 1 wherein the fatty acid moiety is unsaturated.

6. A process as defined by claim 1 wherein the nonsaccharide ester is a glyceryl ester.

7. A process as defined by claim 6 wherein the glyceryl ester is a mixed fatty acid glyceride.

8. A process as defined by claim 1 wherein the nonsaccharide ester is an ester of a fatty acid and a volatile alcohol.

9. A process as defined by claim 8 wherein the volatile alcohol is a volatile lower monohydn'c alcohol.

10. A process as defined by claim 8 wherein the volatile alcohol which is liberated during the process is removed from the reaction mixture by distillation substantially immediately as it is liberated.

11. A process as defined by claim 1 wherein the process is conducted under substantially anhydrous conditions.

12. A process as defined by claim 1 wherein the solvent employed is less volatile than the alcohol of the non-saccharide ester.

13. A process as defined by claim 1 wherein the alkaline catalyst is one which produces the characteristic phenolphthalein magenta color when added in a 1% w./v. concentration in a 0.5% w./v. phenolphthalein solution in a solvent containing equal parts by volume of boiled N,N-dimethylformamide and carbon dioxide-free water.

14. A process as defined by claim 1 wherein the solvent is N,N-dimethylformamide.

15. A process as defined by claim 1 wherein the temperature of the process is maintained within the range of between about and C. during the process.

16. A process for producing an ester of a fatty acid containing between about 6 and 30 carbon atoms and a saccharide selected from the group consisting of sucrose and raftinose, which comprises treating a member of the group consisting of sucrate and rafiinate anions with an ester of a fatty acid containing between about 6 and 30 carbon atoms and a non-saccharide alcohol, in the presence of an alkaline catalyst, at a temperature in the range from between about 20 and 180 C., and in the presence of a solvent.

17. A process for producing a mono-ester of a fatty acid containing between about 6 and 30 carbon atoms and a saccharide selected from the group consisting of sucrose and rafiinose, which comprises treating a saccharide of the group consisting of sucrose and raflinose with an ester of a fatty acid containing between about 6 and 30 carbon atoms and a non-saccharide alcohol, in the presence of an alkaline catalyst, at a temperature in the range from between about 20 and 180 C., and in the presence of a solvent, the proportion of saccharide being at least about 3 moles for each mole of non-saccharide ester employed.

18. A process for producing a mono-ester of a fatty acid containing between about 6 and 30 carbon atoms and a saccharide selected from the group consisting of sucrose and raflinose, which comprises treating a saccharide of the group consisting of sucrose and raffinose with an ester of a fatty acid containing between about 6 and 30 carbon atoms and a non-saccharide alcohol, in the presence of an alkaline catalyst, at a temperature in the range from between about 20 and 180 C., and in the presence of a solvent, the molecular proportions. of non-saccharide ester to saccharide being between about 1:2 and 1:3, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 1,959,590 Lorand May 22, 1934 2,147,241 Cantor Feb. 14, 1939 2,399,959 Tucker May 7, 1946 2,586,897 Woodstock Feb. 26, 1952 2,594,453 Kosmin, et a1 Apr. 29, 1952 2,602,789 Schwartz et a1 July 8, 1952 2,700,022 Clayton et al. Jan. 18, 1955 OTHER REFERENCES Wright et al.: Oil and Soap 21, pp. -148 (1944). Wolff et al.: Journal of American Oil Chem. Soc. 25, p. 258-260 (1948).

Claims (1)

1. A PROCESS FOR PRODUCING AN ESTER OF A FATTY ACID CONTAINING BETWEEN ABOUT 6 AND 30 CARBON ATOMS AND A SACCHARIDE SELECTED FROM THE GROUP CONSISTING OF SUCROSE AND RAFFINOSE, WHICH COMPRISES TREATING A MEMBER OF THE GROUP CONSISTING OF SUCROSE AND RAFFINOSE WITH AN ESTER OF A FATTY ACID CONTAINING BETWEEN ABOUT 6 AND 30 CARBON ATOMS AND A NON-SACCHARIDE ALCOHOL, IN THE PRESENCE OF AN ALKALINE CATALYST, AT A TEMPERATURE IN THE RANGE FROM BETWEEN ABOUT 20 AND 180*C., AND IN THE PRESENCE OF A SOLVENT.