Esterification methanol

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... 

Surprisingly, there is limited nonproprietary experimental data on methanol esterification with acetic acid (29). Studies have been confined to liquid-phase systems distant from equilibrium (30), in regions where hydrolysis is unimportant. A physical study of the ternary methanol—methyl acetate—water system is useful for design work (31). Methyl acetate and methanol form an azeotrope which boils at 53.8°C and contains 18.7% alcohol An apparent methanol—water azeotrope exists, boiling at 64.4°C and containing about 2.9% water. These azeotropes seriously complicate methyl acetate recovery. Methyl acetate is quite soluble in water, and very soluble in water—methanol mixtures, hence two liquid phases suitable for decanting are seldom found. 

Their laboratory PVMR consisted of a reservoir in which the reactants were placed together with Nafion pellets, which acted as the catalyst. The liquid in the reservoir was continuously recirculated through the membrane tube, which was placed externally to the reactor. The membrane, itself, was also shown to be catalytic. A flow of inert gas (rather than vacuum) was used to remove the vapors and water from the membrane permeate. For the methanol esterification reaction the improvement in yield was modest (final conversion 77 % vs. 73 % corresponding to equilibrium), because the membrane was not very permselective towards the reaction products. Significant improvements, on the other hand, were observed with the butanol reaction (final conversion 95 % vs. 70 % corresponding to equilibrium), as the membrane is more permselective towards the products of this reaction. Exchanging the acidic protons in the Nafion membranes with cesium ions significantly improved the permselectivity, but also reduced membrane permeance. 

Chemical equilibrium is a key issue in process design. Chemical equilibrium might set in many cases an upper limit for the achievable conversion, if nothing is done to remove one of the products from the reaction space. Because the equilibrium conversion is independent of kinetics and reactor design, it is also convenient to use it as reference. Note that important industrial reactions take place close to equilibrium, as the synthesis of ammonia and methanol, esterification of acids with alcohols, dehydrogenations, etc, particularly when the reaction rate is fast. Therefore, the investigation of chemical equilibrium should be done systematically in a design project. 

Patnaik, P., and J. Khoury. 2005. Determination of acid herbicides in water by GC-MS A modified method using single extraction and methanol esterification. American Laboratory News Edition, 37(7) 12-16. 

Aspartic acid and glutamic acid residues in wool can be esterified [13,242] using an alcohol and dilute hydrochloric acid. With methanol, esterification occurs at room temperature, but raised temperatures are needed for esterification with higher alcohols. 

The major nitrile products produced in addition to acrylonitrile, HCN, and acetonitrile have significant commercial value in their own right. HCN is used mainly in the manufacture of methyl methacrylate. Methyl methacrylate is prepared by acid dehydration and methanol esterification of acetone cyanohydrin produced from the reaction of HCN and acetone. HCN is also a feedstock for the production of methionine, an important animal feed supplement, and is used to produce pesticides and herbicides. For example, HCN is utilized to manufacture disodium iminodiacetate, which is a key intermediate in the production of the widely used herbicide Roundup (Monsanto Co., St. Louis U.S.A.). It is also valuable as a feedstock for the production of adiponitrile by the hydrocyana-tion of butadiene. Adiponitrile is a feedstock for the manufacture of Nylon. In... 

Two derivatization procedures, pentafluorobenzylation and BF3/methanol esterification, were compared for their applications to GC analysis of phenoxy acid herbicides... 

The parameters considered were the reaction time, the amount of reagent (penta-fluorobenzylbromide, PFBBr) or catalyst (BF3), and the reaction temperature. On derivatiz-ing with pentafluorobenzylation, the most critical factors were foimd to be the concentration of PFBBr and the interaction "temperature-time," which improve the derivatization efficiency. Therefore, after optimization, BF3 /methanol esterification followed by GC—MS is as sensitive as pentafluorobenzylation used with GC-ECD, and more reproducible. 

Generation of Solutions of Anhydrous Hydrogen Chloride in Methanol. Esterification of alcohols by AcCl proceeds in the absence of HCl scavengers. For example, on addition of AcCl to methanol at rt, a solution of hydrogen chloride and methyl acetate in methanol forms rapidly. This reaction provides a more practical method for access to solutions of HCl in methanol than the apparently simpler method of bubbling anhydrous HCl into methanol because of the difficulty of controlling the amount of anhydrous HCl delivered. Solutions of anhydrous HCl in acetic acid can presumably be prepared analogously by addition of AcCl and an equimolar amount of H2O to HOAc. 

In these experiments, the concentrations of reactants and products at the exit of the reactor were observed under steady state conditions for different liquid velocities and molar ratio of reactants in a temperature range of 298 - 363 K. Typical results are shown in Fig. 5.1 for acetic acid-methanol system. For acetic acid with butanol and maleic acid with methanol esterification the results are shown in Fig 5.2 and 5.3 respectively. From these data the conversion of acid as a function of liquid velocity was also evaluated for all the systems. For example, the acetic acid conversion obtained for esterification with methanol is presented in Fig. 5.4 and 5.5 for 318 and 328 K respectively. 

The conversion of acetic acid obtained for acetic acid with methanol esterification is shown in Fig. 5.6 for different liquid velocities and mole ratios. As expected the conversion falls with increase in velocity. The agreement with model predictions and experimental data for different reactant concentration was very good. 

Carbon-tnesoporous silica (CS) composite functionalized with sulfonic acid Carbonization of sucrose impregnated in SBA-15 mesopoiDus silica and its subsequent sutfonation Esterification of palmitic acid and methanol, palmitic acid, and TE of soybean oil and methanol Esterification conversion = 98% TE yield 99% 2012 Fang et al. (2012)... 

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