GB702195A - Improvements in or relating to the production of synthetic products from carbon monox - Google Patents

Abstract

Oxygenated organic compounds are made by continuously reacting an olefine, CO and H2 in the presence of a volatile Co compound as catalyst, by passing the reactants and catalyst through a reaction zone operated under the conditions of the Oxo synthesis reaction without the introduction thereto, before or during the reaction, of metallic Co or a solid Co compound, the catalyst constituting 0.01-0.6 per cent. by weight on fresh olefine fed to the reaction zone, and the flow rates of the reactants being sufficient to effect only partial conversion of the olefine, and thereafter separating olefine from the synthesis reaction product and recycling at least part of the separated olefine to the reaction zone. Volatile Co compounds are defined as volatile Co compounds obtained by the reaction of CO in the presence or absence of H2 with Co compounds such as the oxide or sulphide or with Co metal and they are used in the reaction of the gas phase or in solution in a solvent such as xylene. Preferably they are volatilized into the water gas stream. Dicobalt octacarbonyl and cobalt tetracarbonyl hydride are specified catalysts. It is stated that the use of low catalyst concentrations and short liquid phase residence times reduces the yield of high boiling by-products. In a modification, particularly applicable when lower volatile olefines are used, e.g. ethylene and propylene, an inert solvent is recycled instead of olefine. A preferred solvent is a fraction obtained from the Oxo synthesis product which boils above the predominantly aldehydic product. With olefines of more than three carbon atoms it is generally preferred to run to a conversion of 30-60 per cent. by weight per pass. Preferred pressures are above 50, e.g. 50-250, especially 100-200 atmos., and preferred temperatures are 100-180 DEG C. The amount of catalyst added increases with increases in flow rates and a table is given illustrating this feature in the conversion of propylene to butyraldehydes. Paraffins formed, e.g. isooctane from diisobutylene, should be removed it being generally preferred when using C8 feedstocks that the total paraffin concentrations in the total feed in a recycle process should be about 10-50 per cent. by weight. In an illustration diisobutylene is converted to trimethylhexanol, the initial aldehyde product being hydrogenated, the catalyst is made by passing water gas over cobalt oxide previously reduced with water gas at atmospheric temperature, the water gas is reacted with fresh diisobutylene, recycle diisobutylene and isooctane with partial conversion of the olefine, the product is separated from gases in a high and a low pressure separator and after heating is passed through alumina to remove Co compounds, fractionated at atmospheric pressure to remove unreacted olefine and isooctane which are recycled after purging of the paraffin, the aldehydic product is hydrogenated on a nickel-kieselguhr catalyst and trimethylhexanol is recovered. The butene polymer "codimer" may be used in the above process. In examples (1) and (2) increased selectivities with decreasing residence time are tabulated using propylene, (3) illustrates the improved selectivity with reduced catalyst concentrations using propylene and in (4), (5) and (6) diisobutylene, a propylene trimer and diisobutylene are respectively treated as in the above illustration; full reaction conditions are given, and the aldehydic products are hydrogenated to the corresponding alcohols. Specifications 702,192, 702,196, 702,221, 702,222 and 702,242 are referred to.