Propylene glycol esterification

Alginate is a polymer composed of uronic acid monomers. While this acidic polysaccharide can be recovered from bacteria, the commercial source is brown seaweed. Both propylene glycol esterification and acetylation of the polymer cause an increase in the thickening capabilities of the gum. The acetylation of alginate by pseudomonal species demonstrates alternative biochemical methods for polysaccharide modification. 

The properties of polymers formed by the step growth esterification (1) of glycols and dibasic acids can be manipulated widely by the choice of coreactant raw materials (Table 1) (2). The reactivity fundamental to the majority of commercial resins is derived from maleic anhydride [108-31-6] (MAN) as the unsaturated component in the polymer, and styrene as the coreactant monomer. Propylene glycol [57-55-6] (PG) is the principal glycol used in most compositions, and (i9f2v (9)-phthahc anhydride (PA) is the principal dibasic acid incorporated to moderate the reactivity and performance of the final resins. 

Polyesters from propylene glycol and dicarboxylic acids, especially adipic and sebacic acid, are commercial products suggested for PVC as well as for cellulose esters. The well known Paraplex resins of Rohm Haas, which are compatible with nitrile and GRS rubber, belong to this group. Other products are the Ultramolls of Farbenfabriken Bayer. Some polyesters of this type have a tendency to exude on storage, especially if esterification is not complete. 

Many food colloids are stabilized from proteins from milk or eggs [817]. Milk and cream, for example, are stabilized by milk proteins, such as casein micelles, which form a membrane around the oil (fat) droplets [817]. Mayonnaise, hollandaise, and bearnaise, for example, are O/W emulsions mainly stabilized by egg-yolk protein, which is a mixture of lipids (including lecithin), proteins, and lipoproteins [811,817]. The protein-covered oil (fat) droplets are stabilized by a combination of electrostatic and steric stabilization [817]. Alcohols may also be added, such as glycerol, propylene glycol, sorbitol, or sucrose sometimes these are modified by esterification or by... 

Lehtonen et al. (1998) considered polyesterification of maleic acid with propylene glycol in an experimental batch reactive distillation system. There were two side reactions in addition to the main esterification reaction. The equipment consists of a 4000 ml batch reactor with a one theoretical plate distillation column and a condenser. The reactions took place in the liquid phase of the reactor. By removing the water by distillation, the reaction equilibrium was shifted to the production of more esters. The reaction temperatures were 150-190° C and the catalyst concentrations were varied between 0.01 and 0.1 mol%. The kinetic and mass transfer parameters were estimated via the experiments. These were then used to develop a full-scale dynamic process model for the system. 

Mares et al. [52] recently concluded that hydrogen-ion catalysis during this esterification was not likely and that catalysis by undissociated acid occurred together with a reaction in which, kinetically at least, no form of catalysis was involved. On the other hand, Vansco-Szmercsanyi et al. [53] concluded that polyesterification of maleic, fumaric and succinic acids with ethylene glycol or 1,2-propylene glycol was catalysed by protons. Much work clearly remains to be done on defining the detailed mechanism of catalysis by the acidic species during esterifications. 

Solubility soluble in dilute organic acids and water, forming stable, viscous, colloidal solutions at pH 3. Depending upon the degree of esterification, propylene glycol alginate is also soluble in aqueous ethanol/water mixtures containing up to 60% w/w of ethanol (95%). 

In the present work we have studied the dynamics of formation and structure of the air-water interface in the presence of (3-lg - - PS at 20°C and at pH 7 in a drop tensiometer. As PS with interfacial activity we have used propylene glycol alginates (PGA). To evaluate the effect of the degree of PGA esterification and viscosity, different commercial samples were studied. Xanthan gum (X) and X-carrageenan (X-c) were studied as nonsurface active polysaccharides. 

Degree of Esterification and Viscosity of Propylene Glycol Alginates... 

The protein-covered oil (fat) droplets are stabilized by a combination of electrostatic and steric stabilization [19]. Alcohols may also be added, such as glycerol, propylene glycol, sorbitol or sucrose sometimes these are modified by esterification or by reacting them with ethylene oxide [1]. There are several reviews of food emulsifiers [1, 20-22]. 

Propylene glycol mono-methyl-ether acetate (PMA) is produced by the esterification of propylene glycol mono-methyl ether (PM) in acetic acid (HOAc) ... 

An example of a typical batch preparation of a polyester is one where 1.2 moles of propylene glycol, 0.67 mole of maleic anhydride, and 0.33 mole of phthalic anhydride are combined. Propylene glycol is used in excess to compensate for loss during the reaction. The condensation at 150-200 °C lasts for 6-16 hours, with constant removal of water, the byproduct. An aromatic solvent, like toluene or xylene, is often added to the reaction mixtures to facilitate water removal by azeotropic distillation. Esterification catalysts, like toluene sulfonic acid, reduce the reaction time. In addition. 

Dehnition Obtained by esterification of anthranilic acid with ethanol in presence of acid catalysts Empirical C9H11NO2 Formula NH2C6H4COOC2H5 Properties Colorless to amber liq. fruity odor sol. in alcohol, propylene glycol, fixed oils m.w. 

CAS 105-54-4 EINECS/ELINCS 203-306-4 UN 1180 (DOT) FEMA 2427 Synonyms Butanoic acid, ethyl ester Butyric acid, ethyl ester Butyric ether Ethyl butanoate Ethyl n-butyrate Ciassification Butanoic acid ester Dehnition Obtained by esterification of n-butyric acid with ethyl alcohol in presence of Twitchell s reagent or MgCb Empirical C6H12O2 Formula CH3CH2CH2COOC2H5 Properties Colorless liq., banana-pineapple odor sol. in water, fixed oils, propylene glycol misc. with alcohol, ether insol. in glycerin 121 C m.w. 116.18 dens. 0.874 m.p. -100.8 C b.p. 

Definition Obtained by esterification of decanoic acid and ethyl alcohol in presence of HCI or H2SO4 Empiricai C12H24O2 Formuia CH3(CH2)8COOC2Hs Properties Colorless liq. fragrant odor sol. in fixed oils misc. with alcohol, chloroform, ether insol. in water, glycerin, propylene glycol m.w. 200.32 dens. 0.862 (20 C) m.p. -20 C b.p. 243-245 C flash pt. 216 F ref. index 1.425 (20 C)... 

Definition Obtained by esterification of isovaleric acid with ethyl alcohol in presence of cone. H2SO4 Empirical C7H14O2 Formula (CH3)2CHCH2COOC2H5 Properties Colorless oily liq., apple odor sol. in propylene glycol si. sol. in water 135 C misc. with alcohol, fixed oils, benzene, ether m.w. 130.21 dens. 0.868 (20/20 C) b.p. 135 C m.p. -99 C flash pt. 77 F ref. index 1.395-1.399 Toxicology LD50 (oral, rabbit) 7031 mg/kg, (IP, rat) 1200 mg/kg mod. toxic by IP route mildly toxic by ing. skin irritant TSCA listed Precaution Flamm. liq. when exposed to heat, flame, or sparks... 

Figure 4.11 Effect of the monomer feed ratio on the conversion of the acid end groups (a), molar fraction of unreacted succinic acid (b), and propylene glycol (c) as a function of time in the esterification of PPSu at 190°C [43].

Carboxylic acids and PO give a mixture that contains the monoesters of the primary and the secondary alcohol groups of PG. The monoesters may then react with additional acid to form the glycol diester. With a sufficient concentration of epoxide, the monoester may add PO to yield the ester of dipropylene glycol, higher poly(propylene glycols) and their esters, and the glycol diester. The esterification is catalyzed with sodium or potassium hydroxide, and anhydrous chromium... 

The properties of monoglycerides can also be modified by esterification of one of the hydroxyl groups with acetic, lactic, fumaric, tartaric or citric acids. Similar emulsifiers are synthesised by reacting propylene glycol with saturated fatty acids to give a mixture of mono- and diacyl esters, which can be molecularly distilled to prepare concentrates containing about 90% propylene-glycol monostearate. 

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