Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfur containing
Patent
1983-10-07
1986-01-14
Lesmes, George F.
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfur containing
568 21, C07C14912, C07C14800
Patent
active
045647097
DESCRIPTION:
BRIEF SUMMARY
THE FIELD OF THE TECHNOLOGY
The present invention relates to a process for the production of dialkyltrisulfides; more specifically the invention concerns a method for the selective synthesis of dialkyl-trisulfides.
Dialkyl-polysulfides, such as ditertiarybutyl-polysulfide, ditertiarynonyl-polysulfide, ditertiarydodecyl-polysulfide and the like, have an excellent extreme-pressure efficacy, and are used as extreme-pressure additives to lubricating oils.
Among them dialkyl-polysulfides, dialkyl-trisulfides such as ditertiarybutyl-trisulfide, ditertiarynonyl-trisulfide, ditertiarydodecyl-trisulfide and the like have a minimum grade of copper-strip corrosivity specified under Japan Industrial Standard JIS.K-2513 "Testing Method for Copper Corrosion of Petroleum Products" and are exceedingly useful extreme-pressure additives.
BACKGROUND OF THE TECHNOLOGY
A process for the production of dialkyl-polysulfides is disclosed by U.S. Pat. No. 3,022,351, according to which dialkyl-polysulfides are obtained as a mixture of dissolved sulfur, dialkyl-disulfides, dialkyl-trisulfides, dialkyl-tetrasulfides, dialkyl-pentasulfides and dialkyl-hexasulfides by reacting alkyl-mercaptans and sulfur in the presence of oxides, hydroxides, alcoholates or sulfides of alkali metals or alkaline earth metals or amines as a catalyst and alcohols as an auxiliary catalyst.
Dialkyl-polysulfides obtained by said process contain highly copper-strip corrosive components such as dissolved sulfur, dialkyl-tetrasulfides, dialkyl-pentasulfides, dialkyl-hexasulfides and the like at considerably high contents, and it is excessively difficult to separate purely dialkyl-trisulfides, which have a minimum grade of said copper-strip corrosivity, from said dialkylpolysulfides.
As a classical process for the production of dialkyl-trisulfides, a process is known in which alkyl-mercaptans are reacted with sulfur dichloride in accordance with the following reaction equation (1).
However, sulfur dichloride (SCl.sub.2) is existing under equilibrium with sulfur monochloride as shown in the following reaction equation (2). Accordingly, sulfur dichloride always contains approximately 10% of sulfur monochloride (S.sub.2 Cl.sub.2).
For this reason, the sulfur monochloride also reacts with alkyl-mercaptans to produce dialkyl-tetrasulfides as shown in the following reaction equation (3).
Thus, dialkyl-tetrasulfides, which are highly copper-strip corrosive, are contained in the reaction mixture obtained through the classical process. In order to isolate dialkyl-trisulfides from the reaction mixture, it is necessary to distill out dialkyl-trisulfides by using high-vacuum distillation equipment. Moreover, during the distillation, sulfur by-produced by decomposition of the bottom liquid at the distillation column is sublimated and easily mixes and dissolves into the products of dialkyl-trisulfides. Therefore, the above process has a defect to increase the copper-strip corrosivity of the products dialkyl-trisulfides.
As a process for selectively preparing dialkyl-trisulfides, the process is reported on J. Org. Chem. Vol. 32, page 3833 (1967) and J. Org. Chem. Vol. 31, page 601 (1966) by B. D. Vineyard, wherein the products dialkyl-trisulfides are obtained as a distillate after n-butylamine and alcohol are distilled off at a reduced pressure distillation of a reaction mixture obtained from the reaction of alkyl-mercaptans and sulfur in alcoholic solvent in the presence of n-butylamine as catalyst. However, this process also has the same defect as shown in the case of the classical process using sulfur dichloride, because the produced dialkyl-trisulfides are obtained as a distillate. Therefore, it cannot be employed as an industrial manufacturing process of dialkyl-trisulfides.
It is an object of the present invention to provide a process for the selective production of dialkyl-trisulfides employable as an industrial manufacturing process.
Inventors had eagerly researched to achieve the above object. As a result, they found that the reaction to produce dialkyl-polysulfide
REFERENCES:
patent: 3022351 (1962-02-01), Mihm et al.
patent: 3275693 (1966-09-01), Bapseres et al.
patent: 3308166 (1967-03-01), Biensan et al.
patent: 3392201 (1968-07-01), Warner
Koyama Yuichiro
Moriyama Hitoshi
Nakazawa Hiroshi
Yamashita Toshiaki
Gibson S. A.
Lesmes George F.
Pennwalt Corporation
LandOfFree
Process for the production of dialkyl-trisulfides does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the production of dialkyl-trisulfides, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the production of dialkyl-trisulfides will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-431550