Esterification product

Uses. Neopentyl glycol is used extensively as a chemical intermediate in the manufacture of polyester resins (see Alkyd resins), polyurethane polyols (see Urethane polymers), synthetic lubricants, polymeric plasticizers (qv), and other polymers. It imparts a combination of desirable properties to properly formulated esterification products, including low color, good weathering and chemical resistance, and improved thermal and hydrolytic stabiUty. 

Many of the physical properties are not affected by the optical composition, with the important exception of the melting poiat of the crystalline acid, which is estimated to be 52.7—52.8°C for either optically pure isomer, whereas the reported melting poiat of the racemic mixture ranges from 17 to 33°C (6). The boiling poiat of anhydrous lactic acid has been reported by several authors it was primarily obtained duriag fractionation of lactic acid from its self-esterification product, the dimer lactoyUactic acid [26811-96-1]. The difference between the boiling poiats of racemic and optically active isomers of lactic acid is probably very small (6). The uv spectra of lactic acid and dilactide [95-96-5] which is the cycHc anhydride from two lactic acid molecules, as expected show no chromophores at wavelengths above 250 nm, and lactic acid and dilactide have extinction coefficients of 28 and 111 at 215 nm and 225 nm, respectively (9,10). The iafrared spectra of lactic acid and its derivatives have been extensively studied and a summary is available (6). 

The oxidation reactor effluent and methanol ate sent to the esterification reactor, which operates at up to 250°C and a pressure sufficient to maintain the Hquid phase. This latter is about 2500 kPa (25 atm). The oxidation products are converted to methyl -toluate and dimethyl terephthalate without a catalyst. Excess methanol is suppHed, and steam and vaporized methanol ate removed and enter a methanol recovery column. The esterification products flow to a cmde ester column, which separates the toluate from the terephthalate. The overhead stream of methyl -toluate is returned to the oxidation reactor, and the bottoms stream of dimethyl terephthalate goes to a primary distillation. The distillate is dissolved in methanol, crystallized, and sohd dimethyl terephthalate is recovered. The dimethyl terephthalate can then be either recrystallized or distilled to yield the highly pure material needed for the polyesterification reaction. 

ThioglycoHc acid can be identified by its in spectmm or by gas chromatography. Most of the by-products and self-esterification products are also detected by liquid chromatography, eg, thiodiglycolic acid, dithiodiglycolic acid, linear dimers, and polymers. Iron content can be assayed by the red sensitive complex of 1,10-phenanthroline [66-71-7] and ferrous ion of a mineralised sample. Ferric ion turns an aqueous ammonia solution deep red-violet. 

About 69% of the total 1988 U.S. consumption of isobutyraldehyde, went into the production of isobutyl alcohol and isobutyraldehyde condensation and esterification products. The other principal isobutyraldehyde derivative markets (as a percentage of total 1988 U.S. isobutyraldehyde consumption) are neopentyl glycol (15%) isobutyl acetate (6%) isobutyric acid (5%) isobutyUdene diurea (2.5%) and methyl isoamyl ketone (1.7%). 

Completion of Esterification. Because the esterification of an alcohol and an organic acid involves a reversible equiUbrium, these reactions usually do not go to completion. Conversions approaching 100% can often be achieved by removing one of the products formed, either the ester or the water, provided the esterification reaction is equiUbrium limited and not rate limited. A variety of distillation methods can be appHed to afford ester and water product removal from the esterification reaction (see Distillation). Other methods such as reactive extraction and reverse osmosis can be used to remove the esterification products to maximize the reaction conversion (38). In general, esterifications are divided into three broad classes, depending on the volatility of the esters ... 

The ability of a-hydroxyalkylphosphines with acceptor substituents to eliminate benzene on esterification with diphenylboric acid esters is so characteristic that it is impossible to obtain the intermediate esterification product even in the presence of pyridine. Instead of pyridinium dioxabora-taphosphoniarinane, the complex (110) of dioxaboraphosphorinane with pyridine was isolated [Eq. (66)] (86IZV643). 

Figure 2.28 Dependency of the reaction progress on film thickness and time PET esterification product (prepolymer, Pn o = 2-3), with no catalyst added [8]...

Figure 2.29 Mass-transfer coefficient, M, eg, in molten PET as a function of polycondensation and temperature for the uncatalyzed polycondensation (no additional metal catalyst added) of esterification product (Pn,o = 2-3) at atmospheric pressure [115]...

The monomers TPA and EG are mixed upstream to the esterification reactor in a jacketed slurry preparation unit equipped with a stirrer for highly viscous fluids (e.g. Intermig ). The typical molar ratio of EG to TPA lies between 1.1 and 1.3. The esterification temperature and the molar ratio of monomers are the main controlling factors for the average degree of polycondensation of the esterification product (prepolymer), as well as for its content of carboxyl end groups and DEG. The latter mainly occurs as randomly distributed units of the polymer molecules. 

To a portion of the esterification product (11 mmol) in methanol (18 mL) was added triethylamine (1 mL), then hexylamine (2.53 g, 25 mmol), and the reaction mixture was refluxed overnight. The reaction mixture was cooled to room teitherature and the solid product (2) isolated by vacuum filtration, washed with cold... 

Dimethylxylaramide 1- To a 250 mL round-bottom flask equipped with a magnetic stirrer was added methanol (50 mL) and the xylaric acid - methanol esterification product (6.7 mmol in 10 mL of methanol) prepared as described above. Triethylamine (6.5 mL, 46 mmol) and methylammonium chloride (1.0 g, 14.7 mmol) were then added to the methanol solution and the reaction mixture was refluxed with stirring overnight. The mixture was concentrated and the residue was washed several times with methanol. The... 

Initially, the oxidation conditions chosen for 154 to 157 were the modified ruthenium tetraoxide conditions of Sharpless and co-workers.44 The crude oxidation products were converted to methyl esters 106,160, 161, and 162 and their C-2 epimers 163 to 166 using either diazomethane or trimethylsilyldiazomethane.77 The epimer ratios were determined from integration of the H NMR spectra of the crude esterification products to ensure that accurate ratios were obtained without losing minor isomers during chromatography. The results obtained are summarized in Scheme 60 and Table 15. 

Predict the esterification products of the following acid/alcohol pairs. 

Some sulfur containing polyesters having properties of synergistic AO were described, like a product formed from 2-(2-hydroxyethylthio)-l-methyl-4-[2-(2-hydroxyethylthio)-l-methylethyl]cyclohexane and dimethyl 3,3 -thiodipropionate [183] (141), an esterification product of 3-n-dodecylthiopropionic add with poly(ethylene ycol) [184] (142) or a polycondensate of sebacoyl chloride with 4,4 -dimercaptodiphenyl sulfide [185]. 

A structured, lipid-containing dairy fat is covered by a U.S. patent (95). The invention relates to a frawi-esterification product of a mixture of fatty acids and triglycerides, including milkfat, in the form of cream or butter as the main component. The product has nutritional applications and may also be used as an enteral or parenteral supplement. 

Pretreatment/activation involves swelling mostly chemical pulp fibers with glacial acetic acid and 4-7% moisture (on cellulose basis). Activation ensures uniform acetylation. Esterification involves the treatment of preactivated cellulose with a mixture of acetic acid and acetic anhydride at a consistency of about 10%. The acetic anhydride content of the mixture is approximately 25%, and this amounts to a 10-40% excess over stoichiometric requirement. The reaction proceeds at 50 °C. Hydrolysis refers to a process step in which the DS of the esterification product is reduced from its level of >2.9 to a level between 2.3 to 2.7 by the addition of 5 to 10% water. The temperature during hydrolysis is maintained at 40 to 80 °C. The consequence of hydrolysis is a uniform release of acetyl groups from the cellulose backbone so as to assure uniform solubility. Precipitation involves either the addition of the acetylation mixture into water or dilute acetic acid to produce a flake product, or the addition of water... 

The product mercaptoacetic acid will self-esterify on storage or heating. The self-esterification products are primarily the linear dimer (x = 1), along with some cyclic dimer, oligoesters (x = 2-I-), and solid orthothioester. These self-esterification reactions, with the exception of the formation of the orthothioesters, can be readily reversed in water with dilute acid or base catalyst. 

In studies on the FAEE synthase enzyme, it was demonstrated by Tsujita and Okuda that carboxylesterase is capable of catalyzing the FAEE synthesis reaction (Tsujita, 1992 Tsujita, 1994b). They demonstrated that purified carboxylesterase was able to promote the synthesis of FAEEs in a number of organs. In support of the findings of Tsujita et al., who showed that carboxylesterase can promote the synthesis of FAEE, we reported that purified FAEE synthase also has cocaethylene (an esterification product of ethanol and cocaine) synthetic capacity (Heith, 1995). Cocaethylene synthase, like FAEE synthase, has been shown to have carboxylesterase activity (Dean, 1991), linking FAEE synthesis again to carboxylesterase. 

During the course of reaction, the formation of monoester, owing to its hydrophilicity and surfactant activity, leads to a huge increase in fructose solubility hence, the need for solvent is diminished. In addition, the presence of tert-butanol deters the evaporation of the other esterification product, water. ... 

Over the years a variety of uses have been found for the isobutyraldehyde by Eastman Chemical and others.219 It is converted to isobutyl alcohol, neopentyl glycol, isobutyl acetate, isobutyric acid, isobutylidenediurea, methyli-soamyl ketone, and various hydrogenation and esterification products (1.22). 

Fatty acids are saturated and unsaturated carboxylic acids containing between twelve and twenty-four carbon atoms. Fatty acids with even numbers of carbon atoms occur most frequently in nature. The reactions of fatty acids are identical to those of carboxylic acids. They include esterification, production by acid hydrolysis of esters, saponification, and addition at the double bond. Prostaglandins, thromboxanes, and leukotrienes are derivatives of twenty-carbon fatty acids that have a variety of physiological effects. 

In fact, however, some triester (ro)2P(S)-SR and probably some polymeric product is also formed. In careful synthetic work, the esterification is carried out by slowly adding the theoretical amount of P S q to the hydroxylic compound ROH. If the hydroxylic reactant is a liquid, it acts as its own solvent for the reaction otherwise an appropriate inert solvent is used. In preparing pure phosphorodithioic esters, useful intermediates are the ammonium salts, which are well defined solids formed by the action of dry gaseous ammonia on the crude initial esterification product. These salts can be purified by recrystallization from a solvent such as benzene. The metallic salt is prepared by metathesis in aqueous solution at carefully controlled pH for example ... 

The acylation of anisole with C2 - C12 acids was carried out under the same conditions as that of toluene, except a shorter reaction time (5 h). The acylated anisole formed as the major product para/ortho = 59 1 - 96 1 and no meta isomers) together with esterification products - methyl esters of carboxylic acids and phenol. No phenyl esters formed. The selectivity to esters increases from acetic to dodecanoic acid, reaching 40% for the latter. The acylation of anisole, in contrast to that of toluene, is most efficient with C2 - C6 acids, giving a 62 - 65% yield of acylated products and only 2 - 6% of methyl esters. 

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