Propanols esterification with

The esterification with propanols raises the problem of breaking the azeotrope that the alcohol forms with water. The solution of this problem passes by the use of an entrainer forming a heterogeneous ternary azeotrope. Suitable entrainers are hydrocarbons and oxygenated species, as esters and ethers. The solution is in principle similar for u-propanol with the notable difference that the reaction rate is much slower for the last when using the same catalyst. 

Determination of the composition of different oils and fats is a very common application of the GC analysis of fatty acids. The samples under analysis are usually hydrolysed first and free fatty acids are esterified. Kleiman et al. [138] used the methanol—BF3 method for determining acyl groups in oils. Barnes and Holaday [139] started directly with ground peanuts when analysing the composition of their fats. After hydrolysis for 8 min by heating at 80°C with a methanolic solution of NaOH they carried out the esterification with 10% of methanol—BF3 at 95°C for 5 min. n-Propyl esters were utilized for the analysis of fatty acids in soaps [140]. After evolving fatty acids with the aid of orthophosphoric acid, the esters were prepared by heating with /7-propanol at 90°C for 2 min. 

RC = CCH,X — RCX = C==CH,. /S.y- and 7,S-Acetylenic alcohols can be transformed to the halides in better yields by an alternative procedure, which consists in their esterification with p-toluenesulfonyl chloride and subsequent cleavage of the ester by the action of sodium iodide, lithium chloride, or calcium bromide in an appropriate solvent (60-90%). Halo ethers are prepared by the action of phosphorus tribromide on hydroxy ethers, as in the preparation of /3-ethoxyethyl bromide (66%). In a similar manner, /3-halo esters have been prepared without appreciable dehydration of the /3-hydroxy ester (40-60%). The reaction of cyanohydrins leads to a-halo nitriles. Treatment of 2-nitro-l-propanol with phosphorus pentachloride gives l-chloro-2-nitropropane (47%). ... 

Acid catalysed dehydration of diacetone alcohol to form mesityl oxide followed by selective hydrogenation Acid catalysed esterification of relevant alcohol (methanol, ethanol, propanols, butanols) with acetic acid Tischenko reaction via acetaldehyde is also used for ethyl acetate... 

The chemistry and technological principles of methacrylic acid esterification with aliphatic alcohols is fairly well known. However, the reports dealing with the kinetics studies of esterification of methacrylic acid with n-propanol and isopropanol have not been found. 

The objective of this work was a determination of specific kinetic model describing methacrylic acid esterification with n-propanol and isopropanol with sulfuric acid as a catalyst. 

Results from the comparisons between theoretically calculated (solid lines) and experimentally measured (individual symbols) acid numbers are shown for the esterification of methacrylic acid using n-propyl alcohol (Figures 1-3), and for the esterification of metharylic acid using isopropyl alcohol (Figures 4-6). The average error of fit of experimental results to proposed kinetic model is, respectively, 3.5% and 5.7%, for 9 sets of data concerning the reaction with n-propanol, for 9 sets for the esterification with n-isopropanol. 

Similar activity for esterification with 1-propanol and methanol. 

A layout consisting of a semibatch tank reactor, loaded with a sulfonic acid functionalized poly(styrene divinylbenzene) copolymer (Amberlyst) as catalyst and connected to an external pervaporation module equipped with a commercial PVA membrane, has been used for esterification studies of acetic acid/isopropanofi ° and lactic acid/ethanofi systems. A similar arrangement was reported by Lauterbach and Kreis for the propionic acid/propanol esterification. 

Buchaly et al propose a hybrid process combining reactive distillation and pervaporation for the propionic add/propanol esterification. The membrane module equipped with a commercial PVA membrane is located in the distillate stream in order to selectively remove the produced water. The desired product, n-propyl propionate is removed at the bottom of the distillation column, which is packed with Amberlyst 46 as catalyst, in a reactive zone. 

Esterification of certain aromatic acids with p-aminoethanol and propanol derivatives frequently results in molecules that show local anesthetic... 

Risocaine (28) manages to retain local anesthetic activity even without having a "basic ester" moiety.10 Its synthesis follows classic lines involving esterification of p-nitrobenzoic acid with thionyl chloride followed by reaction with propanol, and then catalytic reduction to complete the scheme. 

Chemat et al. have reported several microwave reactors, including systems that can be used in tandem with other techniques such as sonication [68], and ultraviolet radiation [69]. With the microwave-ultrasound reactor, the esterification of acetic acid with n-propanol was studied along with the pyrolysis of urea. Improved results were claimed compared with those from conventional and microwave heating [68]. The efficacy of the microwave-UV reactor was demonstrated through the rearrangement of 2-benzoyloxyacetophenone to l-(2-hydroxyphenyl)-3-phenylpropan-l,3-dione [69]. 

Using this information, it was possible to optimize the reaction conditions to achieve a particularly high rate enhancement. The rate enhancement of the esterification of benzoic acid with 1-propanol (Scheme 4.1) was increased from 18 to 60 times when the volume was increased from 10 mL to 20 mL at 560 W and increased further to 180 times by increasing the power level to 630 W. 

Later, in a more carefully controlled comparison, Pollington et al. [57] showed that the esterification of acetic acid with 1-propanol also occurred at the same rate under MW and conventional reflux. 

Similar results were obtained in the esterification of acetic acid with 1-propanol performed in the presence of a heterogeneous silica catalyst [39]. The results showed that for this reaction microwave irradiation and conventional heating had similar effects on the reaction rate. 

Esterification of stearic acid and acetic acid with propanol and butanol in the presence of Fe2(S04)3/KSF montmorillonite [37]. The rate enhancement observed (1.5-2.5 times) was ascribed to the higher temperature of the catalyst bed (calculated to be 9-18 K above the bulk temperature). Reaction conditions batch (no stirring) and a stirred single-mode tank reactor, catalyst particle size 5 mm, 10-fold excess of alcohol. 

Esterification of acetic acid with 1-propanol in the presence of Si02 [39]. Reaction conditions reflux, tenfold molar excess of 1-propanol, batch reactor. 

Another method is based on the same principle,112 in which the [14C]labelled methyl ester of D-galacturonan is prepared by esterification of pectic acid with [,4C]diazomethane. In the course of the enzymic de-esterification, aliquots are removed, and the unreacted substrate is precipitated with acidified ethanol or 1-propanol. After centrifugation, the labelled methanol in the supernatant liquor is determined in a liquid scintillation counter. An advantage of this method lies in the possibility of using, as substrates, short-chain oligo-D-galactosiduronates partially esterified with [14C]methanol. These substrates, beginning with the trisaccharide, are not soluble in 1 4 80% phenol-diethyl ether, which is used for the extraction of enzymically released, labelled methanol. 

Izumi and Urabe [105] found first that POM compounds could be entrapped strongly on active carbons. The supported POMs catalyzed etherization of ferf-butanol and n-butanol, esterification of acetic acid with ethanol, alkylation of benzene, and dehydration of 2-propanol [105], In 1991, Neumann and Levin [108] reported the oxidation of benzylic alcohols and amines catalyzed by the neutral salt of Na5[PV2Mo10O40] impregnated on active carbon. Benzyl alcohols were oxidized efficiently to the corresponding benzaldehydes without overoxidation ... 

A process performance study has been conducted by David et al. [47] taking the coupling of pervaporation with the esterification reactions of 1-propanol and 2-pro-panol with propionic acid as a model system. Toluene sulfonic acid was appHed as the homogeneous acid catalyst A PVA-based composite membrane from GFT was used. Fig. 13.5 shows the comparison between the esterification reaction with and without pervaporation. Without pervaporation, the conversion factor reaches a hm-it, which corresponds to the equihbrium of the esterification reaction. Coupling of the esterification to pervaporation allows the reaction to reach almost complete conversion. 

Following extraction/cleanup, quinoxaline-2-carboxylic acid can be detected by electron capture, or mass spectrometric techniques, after gas chromatographic separation on capillary or conventional columns. A prerequisite of quin-oxaline-2-carboxylic acid analysis by gas chromatography is the derivatization of the molecule by means of esterification. Esterification has been accomplished with methanol (419, 420, 422), ethanol (421), or propanol (423) under sulfuric acid catalysis. Further purification of the alkyl ester derivative with solid-phase extraction on a silica gel column (422), thin-layer chromatography on silica gel plate (420), or liquid chromatography on Hypersil-ODS, 3 m, column (423), has been reported. 

As appears from the examination of the equations (giving the best fit to the rate data) in Table 21, no relation between the form of the kinetic equation and the type of catalyst can be found. It seems likely that the equations are really semi-empirical expressions and it is risky to draw any conclusion about the actual reaction mechanism from the kinetic model. In spite of the formalism of the reported studies, two observations should be mentioned. Maatman et al. [410] calculated from the rate coefficients for the esterification of acetic acid with 1-propanol on silica gel, the site density of the catalyst using a method reported previously [418]. They found a relatively high site density, which justifies the identification of active sites of silica gel with the surface silanol groups made by Fricke and Alpeter [411]. The same authors [411] also estimated the values of the standard enthalpy and entropy changes on adsorption of propanol from kinetic data from the relatively low values they presume that propanol is weakly adsorbed on the surface, retaining much of the character of the liquid alcohol. 

Fig. 14. Taft correlation with polar substituent constants (a ) of the vapour phase esterification of acetic acid with alcohols ( ) and of the olefin formation from alcohols (O) over Na-poisoned silica—alumina at 250°C [126]. 1, Methanol 2, ethanol 3, 1-propanol 4, 1-butanol 5, 2-methyl-l-propanol 6, 2-propanol 7, 2-butanol 8, 2-methyl-2-propanol.

For a PW12HPA/MCM-41 catalyst containing 33 wt% HPA, the HPA is present inside the MCM-41 channel system after preparation of the catalyst. However, after use as a catalyst for the liquid-phase esterification of hexanoic acid with 1-propanol (solvent toluene), the HPA particles have sintered into large particles on the external surface of the mesoporous material.4... 

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