GB413307A - Improvements in or relating to the treatment of oils - Google Patents

Abstract

<PICT:0413307/III/1> Mineral or lubricating oils are freed from naphthenic and other undesired components by extraction with a mixture of organic solvents comprising at least one "primary" solvent and at least one "secondary" solvent. A "primary" solvent is defined as one which extracts from the oil a portion of the desired components of high viscosity index, as well as the undesired components; a "secondary" solvent is defined as one which extracts only a part of the undesired components; the mixed "primary" and "secondary" solvents are stated to extract all the undesired components, without removing an appreciable proportion of the desired components. The "primary" solvents specified are nitrogenous aromatic compounds such as nitrobenzene, aniline, nitrotoluenes, o-nitroanisole, nitroxylenes, xylidines such as 2 : 6- and 3 : 6-dimethylaniline, and nitronaphthalenes; o-, m-, and p-chloranilines; o-, m-, and p-chloronitrobenzene; chlorobenzene; o-, m-, and p-dichlorobenzene; o-chlorodiphenyl; benzyl chloride; o-, m-, and p-chlorotoluenes; o-, m-, and p-chlorophenols; phenol; cresols; cresylic acid; 1-chloronaphthalene; halogenated ethers such as methyl 2-chlorethyl ether, methyl 2 : 3-dichloropropyl ether, methyl 2-chlorisopropyl ether, 2-chlorethyl ethyl ether, di(2-chlorethyl) ether, 1 : 2-dichlorethyl ethyl ether, 1 : 2 : 3-trichlorethyl ethyl ether, 2-bromethyl ethyl ether, 2-chlorethyl propyl ether, 2-chlorobutyl propyl ether, 2 : 3-dichloropropyl ethyl ether, chlorobutyl ethyl ethers, chlorisopropyl ethyl ethers, 2-chlorethyl chloropropyl ethers, methyl and propyl 2 : 3-dichloropropyl ethers, di(3-chloropropyl) ether, di(2-chloropropyl) ether, di(2-chlorisopropyl) ether, and di(2-bromethyl) ether; heterocyclic compounds such as dioxane, pyridine, piperidine, furfural, a -furylacetone, thiophene, 2 : 3-dimethylthiophene, 2 : 4-dimethylthiophene, pyrrole, methylpyrroles, quinoline, 2-methyl- and other 2-alkyl-quinolines, and a -picoline; halogenated aliphatic hydrocarbons such as ethylene dichloride, 1 : 2-dichloropropane, 1 : 3-dichloropropane, 1 : 2 - dibromopropane tetra - and penta - methylene chloride, methylene chloride, isopropyl chloride, and butyl chloride; b - and p-naphthols; aryl acetates such as phenyl acetate; phenyl chloracetates; thiocyanates such as isopropyl, ethyl and ethylene thiocyanates; benzonitrile; and mercaptobenzonitriles. With secondary solvents other than ketones, there may also be used, as primary solvents, toluene and like benzene compounds and also aldehydes such as paraldehyde, parapropyl aldehyde, 2 - chloropropionaldehyde, chloracetaldehyde, benzaldehyde, and p-anisaldehyde. As secondary solvents there may be used ketones, alkyl esters of aliphatic acids or of carbonic acid, low-boiling aromatic ethers not containing a nitro group, and nonhalogenated aliphatic ethers. Specified secondary solvents are acetone; methyl ethyl ketone; diethyl ketone; dipropyl ketone; methyl propyl ketone; ethyl propyl ketone; diisopropyl ketone; methyl isopropyl ketone; ethyl isopropyl ketone; diacetone alcohol; acetyl acetone; methyl butyl ketone; ethyl butyl ketone; diisobutyl ketone; alkyl acetates such as methyl, ethyl, propyl, isopropyl, butyl, and tert. butyl acetates; halogenated alkyl acetates such as chloramyl, 2-chlorethyl, 2- and 3-chloropropyl, 2 : 3-dichloropropyl, chlorisopropyl, 2-, 3- and 4-chlorobutyl, and 2 : 3-dichlorobutyl acetates; alkyl halogenacetates such as methyl, ethyl, propyl, and amyl monochloracetates, ethyl and amyl dichloracetates, and methyl, ethyl, propyl and butyl trichloracetates; alkyl formates such as methyl, ethyl, propyl, isopropyl, butyl and sec. amyl formates; halogenalkyl formates such as chloropropyl formates; alkyl propionates such as methyl and ethyl propionates; halogenalkyl propionates; alkyl halogenpropionates such as methyl and ethyl 2-chloropropionate; chloropropyl monochloracetates; ethylene glycol diacetate; cyclohexyl acetate; methyl fluoracetate; ethyl 2-chlorobutyrate; propyl glycollate and lactate; butyl lactate; the ethyl ether of ethyl glycollate; the methyl ether of methyl lactate; the ethyl ether of ethyl lactate; dimethyl, diethyl, and methyl-ethyl carbonates; dimethyl and diethyl oxalates; dimethyl ether; methyl ethyl ether; methyl propyl ether; methyl isopropyl ether; methyl butyl ether; methyl sec.-isobutyl ether; methyl tert.- butyl ether; diethyl ether; anisole; ethyl propyl ether; ethyl isopropyl ether; phenetole; dipropyl ether; propyl isopropyl ether; ethyl butyl ether; propyl butyl ether; diisopropyl ether, dibutyl ether, diphenyl ether, and butyl phenyl ether. Examples are given of the use of the following solvent mixtures: (1) di(2-chlorethyl) ether and acetone; (2) nitro benzene and acetone; (3) dioxane and acetone; (4) dichlorobenzene and acetone; (5) ethylene dichloride and acetone; (6) nitrobenzene and diacetone alcohol; (7) nitrobenzene and methyl ethyl ketone; (8) aniline and acetone; (9) cresylic acid and acetone; (10) nitrobenzene and methyl acetate; (11) di(2-chlorethyl ether) and propyl formate; (12) nitrobenzene and ethyl acetate; (13) di(2-chlorethyl) ether and diisopropyl ether; (14) cresylic acid, di(2-chlorethyl) ether, and diisopropyl ether; (15) dichlorethyl ether, nitrobenzene, and diisopropyl ether; (16) phenol and acetone; (17) nitrobenzene and ethyl acetate. The oil or the solvents may be mixed with a diluent such as propane, butane, propylene or naphtha. The same or different solvent mixtures may be used in succession, or treatment with a single solvent may precede the extraction with the solvent mixture; in such cases the separation of the oil from the solvents may be effected at different temperatures. The extraction may be preceded by treatment with acid, and may be followed by a light acid treatment and then by treatment with clay or fuller's earth. The oil may be dewaxed before and (or) after the treatment. Suitable apparatus for the extraction comprises a vessel 11 in which the oil and the solvent mixture are mixed at a raised temperature; the mixture is then cooled, and when it has separated into layers the solvents and extracted matter are passed to a still 20 from which the solvents are distilled through a condenser 25 to a storage tank 27. The treated oil is passed from the vessel 11 to a tower 32 in which it is freed from solvents by treatment with a stripping gas or vapour such as steam, carbon dioxide, nitrogen, butane or propane; addition of an alkali, particularly ammonia, to the stripping agent may be advantageous. The solvents expelled from the tower 32 are passed to a condenser 37, separated from condensed steam (if necessary) in a vessel 38, and returned to the tank 27. Alternatively, the treated oil may be withdrawn from the top of the vessel 11, and that vessel then used as a still for separating the solvents from the extracted matter. Specification 410,175 is referred to. Chloroalkyl acetates. 2-, 3-, and 4-Chlorobutyl acetates and 2-chloroisobutyl acetate are obtainable from acetic acid and the corresponding alcohols in the presence of sulphuric acid. 2 : 3-Dichlorobutyl acetate is obtainable by chlorinating the acetate of butene-2-o1-4. Chloropropyl monochloracetates are obtainable from monochloracetic acid and chloropropyl alcohols.ALSO:2-Chlorisobutyl acetate and 2-, 3-, and 4-chlorobutyl acetates are obtainable from acetic acid and the corresponding alcohols in the presence of sulphuric acid. 2 : 3-Dichlorobutyl acetate is obtainable by chlorinating the acetate of butene - 2 - ol - 4. Chlorpropyl monochloracetates are obtainable from monochloracetic acid and chloropropyl alcohols.