Showing papers on "Transesterification published in 1979"

Method for producing cacao butter substitute

Abstract: There is provided a method for producing a cacao butter substitute by transesterification of fats and oils containing glycerides rich in the oleyl moiety at the 2-position with an alcohol ester of stearic acid and/or palmitic acid in the presence of a lipase having reaction specificity to the 1,3-position of triglycerides and not more than 018% by weight of water based on the total weight of the reaction mixture By this method, a cacao butter substitute, rich in 1,3-distearyl-2-oleyl compound and 1-palmityl-2-oleyl-3-stearyl compound is obtained, in a high reaction yield with few by-products

Polyisocyanurate foams based on esterified DMI oxidation residue additive

Abstract: Polyisocyanurate foams are disclosed which are characterized by a combination of a high degree of fire resistance with low smoke evolution, low foam friability yet high compressive strength, and, most unexpectedly, the formation of a protective intumescent char over unburnt foam when the foam is subjected to combustion. This combination of advantageous features is achieved by employing in the foam forming reaction a minor amount of a polyol mixture prepared by the transesterification, with a glycol of molecular weight from about 60 to about 400, of a residue obtained from the manufacture of dimethyl terephthalate.

Process for the manufacture of high molecular weight poly-(ethylene terephthalate)

Abstract: In a process for preparing high molecular weight poly-(ethylene terephthalate) in two stages, comprising, in the first stage, reacting a dialkyl ester of terephthalic acid with ethylene glycol in the presence of 35 to 290 ppm of manganese, in the form of a manganese-II salt effective as a catalyst, together with 6 to 95 ppm of cobalt, in the form of a cobalt-II salt effective as a catalyst, at a temperature of 170° to 220° C. to give a low molecular weight precondensate; then adding 45 to 140 ppm of phosphorus in the form of a phosphorus compound effective to minimize discoloration of the product poly-(ethylene terephthalate) due to said transesterification catalysts; and, in the second stage, effecting complete condensation of the precondensate thus obtained, in the presence of catalysts at a temperature of 270°-290° C. and under low pressure, to give high molecular weight poly-(ethylene terephthalate), an improvement is provided wherein, in the second stage, 115 to 230 ppm of germanium, in the form of a germanium-IV salt effective as a catalyst, and 2 to <20 ppm of titanium, in the form of a titanium-IV salt effective as a catalyst, all quantity data for the catalyst components being based on the weight parts of terephthalic acid units, are added to the reaction mixture as the catalysts.

Process for the preparation of polymers with diphenol carbonate end groups

Abstract: This disclosure is concerned with a single step process for the production of diphenol terminated polycarbonates by the transesterification of diphenols, bis-aryl carbonates and polymeric diols with aliphatically bound terminal hydroxyl groups. These diols are selected from polyesters, polyethers, polythioethers and polyacetals. The transesterification is carried out at elevated temperatures under vacuum optionally in the presence of a catalyst with the ratios of the reactants being such as to avoid the retention of any terminal aliphatic hydroxyl groups or aryl carbonate groups.

Gas chromatographic determination of free fatty acids in vegetable oils by a modified esterification procedure

Abstract: Free fatty acids in small vegetable oil samples were determined by gas liquid chromatography after a modified BCl3 or BF3/methanol esterification procedure with methylurea. This compound was found to sufficiently reduce triacylglyceride transesterification during free fatty acid esterification with BC13 or BF3 methanol. Good results were obtained using this new procedure on neutral lipid oils containing known amounts of free fatty acids. Good agreement between the new method and the A.O.C.S. titration method was also demonstrated on commercial and laboratory-extracted crude oils. Because very small oil samples (200 mg) can be analyzed, the new method could be applicable for oilseed physiological studies.

Terephthalic acid esterification kinetics: 2‐(2‐methoxyethoxy)ethyl terephthalates

Abstract: The process of esterification of terephthalic acid is characterized by a mechanism that involves three equilibrium reactions. Two are esterification-hydrolysis equilibria entailing the reactions of the two terephthalic acid carboxyl groups with alcoholic hydroxyl groups, whereas the third one is a transesterification-acidolysis equilibrium that is concerned with the reaction between two terminal terephthalic acid moieties. The products of these three interrelated equilibria are terephthalic acid, its monoester and diester, the particular alcohol, and water. The alcohol used in the present study was 2-(2-methoxyethoxy)ethanol. Equilibrium constants and rate constants were developed from experimental data obtained at 230°C. The esterification-hydrolysis reactions were found to be catalyzed by carboxyl groups, and the rate of transesterification was found to be a function of the terephthalic acid concentration. With the constants developed, the system of nonlinear differential equations, as derived from the mechanism postulated, was integrated numerically using the Runge-Kutta method. Good agreement between calculated and experimental values was observed.

Chemistry of Succinyl Succinic Acid Derivatives. Part V. On the transesterification of succinyl succinates

Abstract: The unique stabilization of the ester link in dialkyl succinyl succinates is explained and a facile route to known as well as to hitherto inaccessible succinyl succinates is suggested. New representatives of this series are described.

Polymers of 2-ketopentafluoropropanesulfonic acid and related acids with ethylene or fluorinated unsaturated monomers

Abstract: 2-Ketopentafluoropropanesulfonic acid is obtained as a product of the reaction of sulfur trioxide and ethyl pentafluoroisopropenyl ether or by transesterification from corresponding esters. Similar sulfonic acids may be obtained by the latter process. The new compounds are useful as monomers for producing polymers, particularly moldable, dyeable, fluoropolymers, and as cationic initiators, e.g., for tetrahydrofuran polymerization.

Ethoxylation

Abstract: The translation of the potentially hazardous, highly exothermic alkoxylation reaction to the rapid, safe and completely reliable industrial technology that it is today has been a noteworthy development. Commercially, the reactions of ethylene oxide with fatty acids are conducted in the presence of alkaline catalysts at temperatures above 100 C. The reaction proceeds in two steps. The first step is relatively slow and the product is predominantly ethylene glycol monoester. The second step occurs after approximately one mole ethylene oxide is reacted and all of the fatty acid is consumed. An increase in the ethylene oxide addition rate is observed, and polyethylene glycol esters are formed. Rapid transesterification also occurs, and the molar proportions of monoester, diester, and free polyol in the product approaches those predicted by the equilibrium assuming random esterification of the polyethylene glycol hydroxyl groups. The composition of polyoxyethylated fatty acids is similar to that obtained by the direct esterification of fatty acid with polyethylene glycol. The distribution of the ethylene oxide chain lengths in the polyethylene glycol portion of the product can be approximated assuming random addition of the epoxide.

2-Ketopentafluoropropanesulfonic acid and related acids

Abstract: 2-Ketopentafluoropropanesulfonic acid is obtained as a product of the reaction of sulfur trioxide and ethyl pentafluoroisopropenyl ether or by transesterification from corresponding esters. Similar sulfonic acids may be obtained by the latter process. The new compounds are useful as monomers for producing polymers, particularly moldable, dyeable, fluoropolymers, and as cationic initiators, e.g., for tetrahydrofuran polymerization.

Process for the preparation of polycarbonates

Abstract: Linear aliphatic polycarbonates having terminal hydroxyl groups are produced by transesterification between a diol and diethyl carbonate, the transesterification being carried out in two stages: (a) in the first stage, the reaction is carried out in the presence of a basic catalyst at a temperature below 150.degree.C, and (b) in the second stage, the reaction is completed in a thin film evaporator, the heating medium supplied to the evaporator being at a temperature above 160.degree.C. The products obtained by this process are useful for the production of polyurethane elastomers which are resistant to hydrolysis.

Mixed sulpho-succinate half ester prodn. - from jojoba oil by saponification, conversion to acyl-alkanol:amide then reaction with maleic anhydride and sulphite

Abstract: The parent patent describes a process for washing a mixt. of sulpho-succinates of formulae RO.CO.CHY.CHY'. -COOM (I) and R'CO.NR''.X.O.CO.CHY.CHY'.COOM (II) (R is residue of fatty alcohols from sperm oil or spermacetic oil. R' is residue of fatty acids from the same oils. X = >=2C opt. branched hydrocarbyl; R4 = H, (hydroxy)alkyl with the total no. of C in X and R'' = 2-6. M is an equivalent of a water-solubilising cation suitable for washing compsns.; Y=H and Y' = SO3M or vice versa). The method involves saponification or transesterification (with 1-3C alcohols) of the oil; converting the liberated fatty acid (or ester) to acylalkanolamides in presence of the liberated fatty alcohol, then reaction of the mixt. with maleic anhydride and a sulphite. In this addn., jojoba oil (A) is used in place of sperm oil or spermacetic oil. Prods. from (A) are generally equivalent to those from sperm oil which is now in short supply. In some respects they are superior e.g. reduced foaming power and lower swelling value in synthetic detergent soaps.

Polyolefin stabiliser - comprises ester prepd. from pentaerythritol or isocyanurate and alkyl-beta:mercapto-propionic acid (ester)

Abstract: Stabilisers for polyolefins contain esterification or transesterification prods. of pentaerythritol or tris-(2-hydroxyethyl)isocyanurate with alkyl-beta-mercaptorpropionic acids or lower esters of these acids. The acid alkyl radicals are pref. 6-28C. The acids are pref. prepd. by reacting beta-mercaptopropionic acid with an alpha-olefin in the presence of an organic peroxide or azonitrile catalyst. The prods. impact resistance to heat and UV light to polyolefin resins.