Reppe butanol process

Reductive carbonylation of alkenes occurs with Fe(CO)5. The water-gas-shift reaction catalysed by Fe(CO)5 generates H2 from water and CO as shown in eq. (7.1). CO is a reducing agent of water. 1 -Butanol had been produced once commercially by the reaction of propylene with CO in water catalysed by Fe(CO)5. The process was called Reppe butanol process. 

Actual operating capacities of Reppe carbonylation processes are difficult to estimate since only a few data are available in the literature. However, it is known that some of the syntheses are carried out on an industrial scale, e. g. the synthesis of acrylates from acetylene, carbon monoxide and alcohols (BASF) [1004, 1005], the acetic acid synthesis from methanol and carbon monoxide and the synthesis of higher molecular weight saturated carboxylic acids from olefins, carbon monoxide and water. Propionic acid (30,000 tons/year) and to a smaller extent heptadecanoic dicarboxylic acid are manufactured via the carbonylation route at BASF. Butanol is made from propylene in Japan [1003, 1004]. 

Another commercial process, for 1-butanol production by reductive carbonylation of propylene with water, catalysed by Fe(CO)5, was developed by the Reppe group (eq. 1.4). 

If hydrogen is replaced by steam, a mixture of primary butanols can be obtained directly. This is the BASF process (Reppe synthesis) with one unit operating in Japan. It produces an effluent containing 88 per cent n-butanol and 12 per cent isobutanol. The main reaction involved is the following ... 

Even while he was busy with the manufacture of ethylene oxide, Walter Reppe was also involved with the development of Buna synthetic rubber. In 1926, the newly formed I.G. Farben decided to embark on the industrial synthesis of rubber, despite the poor quality of the methyl rubber made during World War I. This time, however, it was agreed that butadiene would be used. Several routes to butadiene were investigated, including decyclization of cyclohexene (a retro-Diels-Alder reaction), but the so-called four-step process (Vierstufen Verfahren) soon won out. This was partly because it used acetylene, and hence surplus carbide from cyanamide manufacture, but also because it drew on the steps - and hence the momentum - of the BASF butanol synthesis. As a member of the former butanol group, Reppe was a natural candidate for the four-step process project. 

Reppe [83] developed the Reppe reaction of carbonylation, vinylation, ethy-nylation and cyclization by reaction of acetylene with carbon monoxide, water, alcohols, amines, aldehydes and ketones, etc. In 1952, the reaction of olefins in place of acetylene, in the presence of metal carbonyl catalysts, produces alcohols. This process is called the new Reppe process, and butanol has been industrially produced by this process since around 1960. 

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