A process for sweetening sour hydrocarbon distillates and sweetening agents therefor

摘要

Hydrocarbon distillates, e.g. naphthas, light and heavy raw gasoline fractions, raw kerosene, diesel fuel, jet fuel, stove oils, furnace oils, and light gas oil fractions, are sweetened by contact in the presence of oxygen with a composition comprising by weight (a) 99,9-10 parts of a phenylene diamine which is a known sweetening agent, and (b) 0,1-90 parts of guanidine and/or a substituted guanidine in which there are 1-5 substituents which may be hydrocarbon radicals, oxahydrocarbon radicals in which the oxygen atoms are ether oxygen atoms, and azohydrocarbon radicals in which the nitrogen atoms are tertiary amino nitrogen atoms, each of the substituents containing 1-18 carbon atoms. Many examples of suitable compounds (a) and (b) are specified, but for (a) it is preferred to use an N:N1-dialkyl phenylene diamine having 1-12 carbon atoms in each alkyl group, N:N1-di-sec. butyl-p-phenylene diamine being especially suitable, while for (b) 1:1:3-trimethylguanidine and 1:1:3:3-tetramethylguanidine are preferred. (a) is generally used in amounts of 1-50, preferably 2-20, lbs. per bbl. of distillate and (b) in amounts of 0,05-10, preferably 0,5-5, lbs. per bbl. of distillate. The composition may either be used directly as a mixture, or as a solution in, for example, benzene, toluene, kerosene, ethanol, isopropanol, acetone or methyl ethyl ketone. Alternatively, the guanidine may be employed in the form of a salt, in which case the caustic normally employed in the process should be sufficient to neutralize the acid component of the guanidinium salt. In a preferred embodiment, the sour hydrocarbon is mixed with 0,1-1% by volume of a 5-30% aqueous solution of an alkali metal hydroxide in the presence of air, in addition to the diamine (a) and the guanidine (b). If required, alkanols, glycols, ether alcohols, alkanolamines, solutizers such as potassium isobutyrate, alkylphenols such as the cresols, polyhydroxy aromatic compounds such as tannic acid, or petroleum acids such as naphthenic acids may be incorporated in the aqueous alkaline solution. The process is usually carried out at 50-125 DEG F., and preferably at 70 DEG -90 DEG F.