GB798541A - New primary alcohols - Google Patents

Abstract

The invention comprises the new primary alcohols 3-ethylheptanol-1 and 3-ethylhexanol-1 and mixtures comprising 3-ethylhexanol-1 and 3-methylheptanol-1. The compounds or compositions may be prepared by the dimerization of butene-1 or of a propylene and butene-1 mixture followed by carbonylation and hydrogenation of the dimerization product. The dimerization of butene-1 gives 2-ethyl-hexene-1 which on carbonylation and hydrogenation gives 3-ethyl-heptanol-1. A mixture of propylene and butylene on dimerization gives 2-methylpentene-1, 2-ethyl-hexene-1 and a mixture of 2-methyl-hexene-1 and 2-ethyl-pentene-1 and on carbonylation and hydrogenation these give 3-methyl-hexanol-1, 3-ethyl-heptanol-1 and a mixture comprising 3-methyl-heptanol-1 and 3-ethyl-hexanol-1 respectively. The dimerization takes place in the presence of one or more aluminium alkyl compounds, such as aluminium tri-ethyl, at elevated temperature in a sealed vessel and may be carried out batchwise or continuously. The dimer product is carbonylated in the presence of a cobalt catalyst by a mixture of carbon monoxide and hydrogen at superatmospheric pressure and temperature. The product is freed from carbon monoxide and is hydrogenated at elevated temperature and pressure in the presence of cobalt retained from the carbonylation or in the presence of a hydrogenation catalyst such as copper-zinc oxide. The cobalt catalyst may be added as an organic compound soluble in the reactants or as a catalyst on a support such as kieselguhr. In the examples: (a) a mixture of propylene and butene-1 is dimerized in the presence of a mixture of aluminium tripropyl, aluminium tributyl and decahydronaphthalene, to give a mixture of 2-methyl-pentene-1, 2-methylhexene-1, 2-ethyl-pentene-1 and 2-ethyl-hexene-1; the co-dimer heptenes are carbonylated in the presence of a cobalt-on-kieselguhr catalyst and the product is hydrogenated to give a mixture of 3-ethyl hexanol-1 and 3-methyl heptanol-1; (b) 2-ethyl-hexene-1 obtained by the dimerization of butene-1 as in (a) is carbonylated in the presence of a cobalt naphthenate catalyst and the product is hydrogenated using a copper-zinc oxide catalyst to give 3-ethyl-heptanol-1.