GB789777A - Improved plasticizer alcohols and esters - Google Patents

Abstract

Alcohols are prepared by reacting an olefinic feed with carbon monoxide and hydrogen at elevated temperatures and pressures in the presence of a cobalt carbonylation catalyst to form an aldehydic reaction product which is hydrogenated to produce alcohols, the olefine feed being obtained by subjecting a petroleum fraction to a steam cracking treatment, separating from the steam-cracked product a naphtha fraction containing olefines with 6 to 8 carbon atoms per molecule together with di-olefines and tertiary olefines, polymerizing substantially all the diolefines and tertiary olefines of said naphtha fraction by the action of aluminium chloride or aluminium bromide as catalyst and separating by distillation the polymers so formed from the distillate which contains olefines with 6 to 8 carbon atoms per molecule. The tertiary olefines referred to are defined as those of formula RR1C=CH2 in which R and R1 are monovalent hydrocarbon radicals. The treatment with aluminium chloride may be carried out batchwise or continuously. In the example naphtha and higher boiling petroleum stocks are cracked at 538-816 DEG C. and 1-10 atmos. with steam or inert gas as diluent; a product boiling in the range 5-120 DEG C. and containing aliphatic olefines and diolefines, cyclo-, mono- and diolefines in addition to paraffins and aromatic compounds; the fraction is treated in a thermal soaker to dimerize selectively the cyclic dienes; the mixture of dimerized cyclic diolefines and unreacted hydrocarbons is distilled and a fraction containing aromatic hydrocarbons and C5-C8 olefines is separated; aluminium chloride is added to this fraction and the polymerization is stopped after 0.25 to 2 hours by the addition of a polar substance, such as water or alcohol, and a washing agent; the product is distilled and the overhead product, consisting essentially of mono-olefins, from which most of the Type III olefines have been removed, and of aromatics, is fractionated and an olefine fraction boiling in the range 57-71 DEG C. is separated; this fraction is mixed with cobalt naphthenate or oleate and treated with a mixture of hydrogen and carbon monoxide at elevated temperature and pressure; the liquid carbonylation product containing cobalt carbonyl in addition to the desired heptyl aldehydes is decobalted by heating under pressure and stripping with water, steam or hydrogen; the liquid aldehyde product is hydrogenated in the presence of a hydrogenation catalyst such as nickel, copper chromite or tungsten, nickel or molybdenum sulphide to give heptyl alcohol. The heptyl alcohol may be esterified by treating with an acid or anhydride, such as phthalic anhydride. The process is carried out similarly with fractions yielding octyl and nonyl alcohols which are converted to their phthalates.