GB643503A - A process for the production of oxygen-containing hydrocarbon derivatives - Google Patents

Abstract

A process for the production of oxygen-containing hydrocarbon derivatives by converting alkenes in the presence of an Oxo-synthesis catalyst with carbon monoxide and hydrogen under pressure, in which in a first stage oxo compounds are formed which consist mainly of aldehydes, and are converted into alcohols in a further stage by hydrogenation, is characterised in that the hydrogen or hydrogen-containing gas remaining after the hydrogenation is mixed with the excess of carbon monoxide and hydrogen from an earlier stage, which mixture may after adjustment of composition be used for the oxo reaction. Gases in the oxo stage may be passed either in co-current or countercurrent flow and the products formed first passed upwards while hydrogen is passed through to remove dissolved and combined carbon monoxide and then are hydrogenated whilst passing downwards. The reaction may be effected in a plurality of stages in separate reaction zones in series, hydrogen being passed back from the last to the first stage is enriched with carbon monoxide in the process and finally used in the first synthesis stage after adjustment of composition so that the ratio of hydrogen to carbon monoxide is at least 1 to 1. The synthesis and hydrogenation are preferably carried out at the same pressure generally between 100 and 300 atmos. Temperatures instanced for the oxo stage are 50-300 DEG C., preferably 100-200 DEG C. and for the hydrogenation 100-350 DEG C., preferably 150-250 DEG C. Throughput rates are 0.5 to 5 litres, pre ferably 1 to 3 litres of alkenes per litre of reaction space per hour. Quantities of gas in the two stages instanced are 50-300, preferably 100-200 litres per sq. cm. of section per hour. In the synthesis the ratio of hydrogen to carbon monoxide is usually between 1 : 1 and 1 : 2 and for the hydrogenation a carbon-monoxide free hydrogen-containing gas is desirable. Oxo-synthesis catalysts specified are the known catalysts for the production of hydrocarbons from carbon monoxide and hydrogen especially cobalt-containing catalysts on a carrier of conventional type and are used in suspension. In an illustration, preheated olefine is passed to a reactor containing cobalt promoted with thorium oxide on diatomaceous earth, preheated carbon monoxide (which may contain hydrogen or other diluents) is forced in together with recycle gases, reaction effected at 80-200 DEG C., preferably 150 DEG C. and 50-240, preferably 200 atmos., the catalyst being in suspension in the liquid phase and the residence time in the reactor being about 10 minutes when the mixture is preferably transferred to a second reactor at a slightly higher temperature, e.g. 10-50 DEG C. higher than the first, with a similar residence time, cooled, passed to a separator, excess gas being recycled to the first stage or vented, the reaction product being passed to the second stage where the aldehydes are partly hydrogenated and the cobalt-carbonyl substantially decomposed, e.g. at 180 DEG C. and 200 atmos., the reaction mixture being cooled, separated and unreacted hydrogenating gas is recycled to this stage and to make up hydrogen requirements for the first stage, the reaction product is passed to the third stage reactor and treated with fresh hydrogen and recycle gas from this third stage at e.g. 200 DEG C. and 200 atmos. when the reaction product is passed with unused hydrogen to a separator after cooling, then to a low pressure separator, excess hydrogen being in part recycled to this stage and to the second stage, the liquid product is passed to a third separator where the catalyst is removed and optionally recycled to the first stage, the liquid product is filtered and compounds isolated in conventional fashion. Specification 629,915 is referred to.