Propanol esterification

Carbonylations (methanol, propanol). Esterifications, manufacture of sulfuric acid, adipic acid, oxamide and so on... 

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 ... 

Fig. 13.5 Concentration profiles in the pervaporation-assisted esterification of 1-propanol and propionic acid.

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... 

Exercise 15-28 In the conversion of 2-propanol to 2-propanone with chromic acid, which is the redox step, esterification or elimination What is the change in oxidation level of carbon in this reaction ... 

By coupling an ultrasonic probe with a microwave reactor and propagating the ultrasound waves into the reactor via decalin introduced into their double jacket design, Chemat et al. studied the esterification of acetic acid with propanol and the pyrolysis of urea to afford a mixture of cyanuric acid, ameline and amelide (Scheme 9.19)136. Improved results were claimed compared to those obtained under conventional and microwave heating. The MW-US technique was also used to study the esterification of stearic acid with butanol and for sample preparation in chemical analysis137,138. 

To avoid difficulties related to the growth of pressure in a sealed vessels as well as temperature measurement, the esterification reaction of acetic acid with propanol was carried out in an open vessel under reflux conditions. It was found that ester concentrations during the course of the reaction were comparable under both conventional and microwave conditions [20]. In a similar reaction (i.e., the esterification of trimethylben-zoic acid with propanol), the kinetic parameters of the reaction under the Arrhenius law were estimated for conventional conditions. Then ester concentrations were calculated theoretically and compared with the results obtained for the reaction under microwave conditions. It was found that the theoretical values correlated well with the experimental results so microwave irradiation did not influence the rate of the reaction [21]. 

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