Acetic acid from -butenes

A process to convert butenes to acetic acid has been developed by Farbenfabriken Bayer AG (137) and could be of particular interest to Europe and Japan where butylenes have only fuel value. In this process a butane—butylene stream from which butadiene and isobutylene have been removed reacts with acetic acid in the presence of acid ion-exchange resin at 100—120°C and 1500—2000 kPa (about 15—20 atm) (see Acetic acid and its derivatives, acetic acid). Both butenes react to yield j -butyl acetate which is then oxidized at about 200°C and 6 MPa (about 60 atm) without catalyst to yield acetic acid. 

The production of acetic acid from n-butene mixture is a vapor-phase catalytic process. The oxidation reaction occurs at approximately 270°C over a titanium vanadate catalyst. A 70% acetic acid yield has been reported. The major by-products are carbon oxides (25%) and maleic anhydride (3%) ... 

The reaction conditions are approximately 100-120°C and 15-25 atmospheres. The oxidation step is noncatalytic and occurs at approximately 200°C and 60 atmospheres. An acetic acid yield of 58% could he obtained. By-products are formic acid (6%), higher boiling compounds (3%), and carbon oxides (28%). Figure 9-1 shows the Bayer AG two-step process for producing acetic acid from n-butenes. ... 

Figure 9-1. The Bayer AG two-step process for producing acetic acid from n-butenes. ...

In addition, undesired species may originate from reactions with impurities present in the fresh feed, such as ethylene giving acetaldehyde and acetic acid, or butenes leading to heavies. For this reason the concentration of non-C3 alkene in the fresh propylene feed has to be limited to a maximum of 0.5%. 

Scbwerdiet, W, Make acetic acid from n-butenes , Hydrocarbon Processing, 49 (11)117-120 (1970). Morrison, J Hfils develops acetic add from butenes route , Oil md Gas J. Internal 11 (10) 26-29 (1971). Rhone-Poulenc/Mdle-Bezons improve acetic add process , Europ. Chem. News, 27 (20 Oct 1972). 

Prospective Processes. There has been much effort invested in examining routes to acetic acid by olefin oxidation or from ethylene, butenes, or j -butyl acetate. No product from these sources is known to have reached the world market the cost of the raw materials is generally prohibitive. 

Acetic acid is obtained from different sources. Carbonylation of methanol is currently the major route. Oxidation of butanes and butenes is an important source of acetic acid, especially in the U.S. (Chapter 6). It is also produced by the catalyzed oxidation of acetaldehyde ... 

Pd2+ salts are useful reagents for oxidation reactions of olefins. Formation of acetaldehyde from ethylene is the typical example. Another reaction is the formation of vinyl acetate by the reaction of ethylene with acetic acid (16, 17). The reaction of acetic acid with butadiene in the presence of PdCl2 and disodium hydrogen phosphate to give butadienyl acetate was briefly reported by Stem and Spector (110). However, 1-acetoxy-2-butene (49) and 3-acetoxy-l-butene (50) were obtained by Ishii and co-workers (111) by simple 1,2- and 1,4-additions using PdCl2/CuCl2 in acetic acid-water (9 1). 

The most important reaction is the oxidative addition of two moles of acetic acid to butadiene to form 1,4-diacetoxy-2-butene (21) with the reduction of Pd2+ to Pd°. In this reaction, 3,4-diacetoxy-l-butene (127) is also formed. In order to carry out the reaction catalytic with regard to Pd2+, a redox system is used. This reaction attracts attention from the standpoint of industrial production of 1,4-butanediol. For this purpose, the formation of 127 should be minimized. Numerous patent applications have been made (examples 113-115), but no paper treating the systematic studies on the reaction has been published. 

Many other compounds have been shown to act as co-catalysts in various systems, and their activity is interpreted by analogous reactions [30-33]. However, the confidence with which one previously generalised this simple picture has been shaken by some extremely important papers from Eastham s group [34], These authors have studied the isomerization of cis- and Zraws-but-2-ene and of but-l-ene and the polymerization of propene and of the butenes by boron fluoride with either methanol or acetic acid as cocatalyst. Their complicated kinetic results indicate that more than one complex may be involved in the reaction mechanism, and the authors have discussed the implications of their findings in some detail. 

The first studies of chlorine addition to the simplest diene, 1,3-butadiene, carried out in solvents of various polarity, showed58 that the reaction always led to mixtures of 1,2- and 1,4-addition products, in ratios almost independent of the solvent polarity. Furthermore, the addition of CI2 in acetic acid gave, besides the 1,2- and 1,4-dichlorides, 3-acetoxy-4-chloro-l-butene and l-acetoxy-4-chloro-2-butene arising from solvent incorporation (equation 27). By comparison of these data with those related to Br2 addition... 

The trapped product gave an immediate test with KI in acetic acid. Its infrared spectrum was similar to that of 3-butene-2-ol with major absorption peaks at 3, 8.7, 9.5, 10.3, and 10.8 microns and minor peaks at 6.3, 7.2, 7.7, 11.6, 12.4, and 12.6 microns. There was no absorption arising from carbonyl. In a 25% solution of hydroperoxide in carbon tetrachloride, the hydroperoxide proton gave rise to a broad band at 8.7 p.p.m. (referred to TMS) in the NMR spectra. 

Purification of the Organoselenium Compounds. After the oxidation of 2-butene with selenium dioxide was completed, the acetic acid solvent and the volatile reaction products were distilled at reduced pressure (10 mm. HgA). The residue, a yellow oil, was purified by adsorption chromatography in a column packed with silica gel. n-Hexane and ethyl ether were used as eluents. The same procedure was applied to the fractionation and purification of the organoselenium compounds obtained from the oxidation of bis(l-methyl-2-acetoxypropyl) selenide with peracetic acid. 

Oxidation of 2-Butene with Selenium Dioxide. The oxidation was conducted in glacial acetic acid at atmospheric pressure and temperatures from 56° to 80°C. Approximately 3 moles of olefin were absorbed per mole of selenium dioxide consumed. The reaction produced 0.85 mole of l-acetoxy-2-butene, 0.03 mole of 3-acetoxy-l-butene, and 0.85... 

Stereochemical specificity fe manifest in the reaction of frans-2,3-epoxybutane with acetic acid, which Wjiustein and Lucas reported to give only ryJAre-2-acetoxy-3-butanol (Eq. 746). Hydrolysis leads to optically inactiveme o-2,3-hutanediol. Similarly, Bdeeeken and Cohen1 had described previously the preparation of racemic [Pg.460]

The C5 aldehyde intermediate is produced from butadiene via catalytic oxidative acetoxylation followed by rhodium-catalyzed hydroformylation (see Fig. 2.30). Two variations on this theme have been described. In the Hoffmann-La-Roche process a mixture of butadiene, acetic acid and air is passed over a palladium/tellurium catalyst. The product is a mixture of cis- and frans-l,4-diacetoxy-2-butene. The latter is then subjected to hydroformylation with a conventional catalyst, RhH(CO)(Ph3P)3, that has been pretreated with sodium borohydride. When the aldehyde product is heated with a catalytic amount of p-toluenesulphonic acid, acetic acid is eliminated to form an unsaturated aldehyde. Treatment with a palladium-on-charcoal catalyst causes the double bond to isomerize, forming the desired Cs-aldehyde intermediate. 

Intramolecular reaction with nucleophilic groups can also lead to heterocycles. For example, good yields of 3-acylbenzofurans result from cyclization caused by intramolecular substitution of the tertiary amino group by a phenol formed by cleavage of a phenol ether by boron tribromide251 (equation 182). 0-Hydroxy benzyl alcohols were used to obtain 4//-chromenes by their reaction with 4-morpholino-3-buten-2-one in acetic acid-acetic anhydride187. 

The liquid phase processes resembled Wacker-Hoechst s acetaldehyde process, i.e., acetic acid solutions of PdCl2 and CuCl2 are used as catalysts. The water produced from the oxidation of Cu(I) to Cu(II) (Figure 27) forms acetaldehyde in a secondary reaction with ethylene. The ratio of acetaldehyde to vinyl acetate can be regulated by changing the operating conditions. The reaction takes place at 110-130°C and 30-40 bar. The vinyl acetate selectivity reaches 93% (based on acetic acid). The net selectivity to acetaldehyde and vinyl acetate is about 83% (based on ethylene), the by-products being CO2, formic acid, oxalic acid, butene and chlorinated compounds. The reaction solution is very corrosive, so that titanium must be used for many plant components. After a few years of operation, in 1969-1970 both ICI and Celanese shut down their plants due to corrosion and economic problems. 

Diphenyl carbonate from dimethyl carbonate and phenol Dibutyl phthalate from butanol and phthalic acid Ethyl acetate from ethanol and butyl acetate Recovery of acetic acid and methanol from methyl acetate by-product of vinyl acetate production Nylon 6,6 prepolymer from adipic acid and hexamethylenediamine MTBE from isobutene and methanol TAME from pentenes and methanol Separation of close boiling 3- and 4-picoline by complexation with organic acids Separation of close-boiling meta and para xylenes by formation of tert-butyl meta-xyxlene Cumene from propylene and benzene General process for the alkylation of aromatics with olefins Production of specific higher and lower alkenes from butenes... 

Applications of POMs to catalysis have been periodically reviewed [33 0]. Several industrial processes were developed and commercialized, mainly in Japan. Examples include liquid-phase hydration ofpropene to isopropanol in 1972, vapor-phase oxidation of methacrolein to methacrylic acid in 1982, liquid-phase hydration of isobutene for its separation from butane-butene fractions in 1984, biphasic polymerization of THE to polymeric diol in 1985 and hydration of -butene to 2-butanol in 1989. In 1997 direct oxidation of ethylene to acetic acid was industrialized by Showa Denko and in 2001 production of ethyl acetate by BP Amoco. 

The unsaturated dibasic acids bear the same relation to the saturated dibasic acids, just considered, as the unsaturated mono-basic acids, acrylic acid, crotonic acid, etc. (p. 172), do to the saturated monobasic acids, acetic acid, etc. They are also the oxidation products of the unsaturated hydrocarbons, alcohols, and aldehydes just as oxalic and succinic acids are of the corresponding saturated compounds. As the simplest dibasic acid containing an ethylene unsaturated group will contain two carboxyl groups and also two doubly linked carbon atoms there must be at least four carbons in the compound. This compound will therefore correspond to succinic acid of the saturated series. Now succinic acid may be derived from either butane by oxidation or from ethane by substitution. Similarly the corresponding unsaturated acid may be derived from butene by oxidation or from ethene by substitution. All of these general relationships may be represented as follows ... 

A further example for the ozonization of an olefin in the presence of a solvent containing active hydrogen is the ozonolysis of 2-butene in acetic acid as solvent. The hydroperoxy ester was isolated as a pure and rather stable liquid. It is different from a crystalline autoxidation product of acetaldehyde (the peroxide of Losch ) which... 

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