Davy Mckee (london) Limited

Davy Mckee Corporation

Keith Turner

John Scarlett

Norman Harris

Mohammad Sharif

Colin Rathmell

Anthony B Carter

Arthur James Reason

John W Kippax

Michael W Bradley

Geoffrey Webb

A copper chromite hydrogenation catalyst of enhanced activity is obtained by an ante-pre-reduction treatment in which a copper chromite catalyst precursor is soaked in a reducing atmosphere at temperatures below a pre-reduction temperature (typically about 140.degree. C.) at which appreciable pre-reduction of the catalyst can be detected. This catalyst is characterized by particles of reduced copper substantially all of which have an average particle size of less than about 300.times.10.sup.-10 m (300.ANG.), which have an average particle size of less than about 100.times.10.sup.-10 m (100.ANG.), and which are substantially uniformly distributed on a chromium-containing support. Typically such catalysts exhibit a copper surface area of about 18.5 m.sup.2 /g as determined by N.sub.2 O decomposition at 20.degree. C., compared to a corresponding copper surface area of 4.5 m.sup.2 /g for a catalyst which has been produced by conventional pre-reduction of the same catalyst precursor.

Process for producing a hydrogenation catalyst of copper chromite

Aliphatic aldehydes are hydrogenated to alcohols containing by product ester which ester is removed and separately hydrogenated to provide additional product.

Hydrogenation of aldehydes

A continuous process is described for the production of a substantially acid free dialkyl maleate, for example diethyl maleate, from a feed stream containing a major amount of dialkyl maleate and a minor amount of the corresponding monoalkyl maleate. This comprises continuously distilling the feed stream in a primary distillation zone, which can comprise a single distillation column or a series of distillation columns connected in series, so as to give (i) a bottom fraction containing monoalkyl maleate and dialkyl maleate in admixture, (ii) a vaporous fraction comprising alkanol, and (iii) an intermediate fraction that is substantially free from alkanol and comprises a major proportion of diethyl maleate and a minor proportion of maleic anhydride. The intermediate fraction (iii) is redistilled in a secondary distillation zone to yield (i) an overhead fraction containing maleic anhydride and (ii) a bottom fraction containing substantially acid free dialkyl maleate. The vaporous stream can be condensed to recover alkanol for recycle to a dialkyl maleate production facility.

Process for the production of a dialkyl maleate

Process for the production of butane-1,4-diol

A process for the production of butane-1,4-diol comprises hydrogenating a di(C.sub.1 to C.sub.3 alkyl) ester of a C.sub.4 dicarboxylic acid, e.g. an ester of a but-2-en-1,4-dioic acid, such as diethyl maleate, in the vapor phase at a temperature of from about 150.degree. C. to about 240.degree. C. and at a pressure in the range of from about 25 bar to about 75 bar in the presence of a reduced copper chromite catalyst, and recovering resulting butane-1,4-diol containing reaction product. The catalyst contains, before reduction, from about 25 to about 45% by weight of copper and from about 20 to about 35% by weight of chromium and preferably has an internal surface area of at least about 30 sq. m. per gram. The process is preferably conducted in two or more reaction zones, which are preferably operated adiabatically, the feed temperature to the first zone being higher than that to at least one subsequent reaction zone.

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Stockton-on-Tees, United Kingdom

Keith Turner