JPH0319221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing dialkyl polysulfides, and more particularly to a method for producing dialkyl trisulfides with improved corrosion resistance to copper plates.

Dialkyl polysulfides such as ditar
Syalibutyl polysulfide, diter-syalydodecyl polysulfide, etc. have excellent extreme pressure performance, especially
Dialkyl trisulfides such as ditertiary butyl trisulfide, ditertiary nonyl trisulfide, ditertiary dodecyl trisulfide, etc. have a corrosion resistance to copper plate according to JIS K-2513 "Petroleum products copper plate corrosion test method". Because it is extremely small, it is a useful substance as an extreme pressure additive for lubricating oils.

Alkali metal and alkaline earth metal oxides and hydroxides using alkyl mercaptans and sulfur as catalysts, as disclosed in U.S. Pat. No. 3,022,351;
In the method for producing dialkyl polysulfide, which is reacted in the presence of an alcoholate, sulfide, or amine catalyst, the dialkyl polysulfide is usually dissolved sulfur, dialkyl disulfide, dialkyl trisulfide, dialkyl tetrasulfide, etc. , dialkyl penta sulfide, dialkyl hexa sulfide, dialkyl heptas sulfide, etc. The dialkyl polysulfides obtained by this method contain dissolved sulfur, dialkyl tetrasulfide, dialkyl penta sulfide, dialkyl hexa sulfide, dialkyl heptas sulfide, etc., which are highly corrosive to copper plates. There is a need for a dialkyl trisulfide in small amounts that is less corrosive to copper plates. As a selective production method for dialkyl trisulfides, alkyl mercaptans and
After reacting with sulfur in an alcohol solvent in the presence of an n-butylamine catalyst to synthesize dialkyl trisulfide, the alcohol and n-butylamine are distilled off, and then the dialkyl trisulfide is distilled under reduced pressure. B, D, VINEYARD method for distillation (J, org
chem vol323833 (1967) and J, org
chem vol 31601 (1966)) has been proposed.

However, this method not only requires high-vacuum reduced-pressure distillation equipment to distill dialkyl trisulfides, but also sulfur produced by decomposition of dialkyl polysulfides sublimes during distillation, and dialkyl trisulfides are Since the dialkyl trisulfide is mixed into the trisulfide, the resultant dialkyl trisulfide has a defect in that it becomes highly corrosive to copper plates, and cannot be used in industrial production methods.

As a classical method for synthesizing dialkyl trisulfides, a method of reacting an alkyl mercaptan with sulfur dichloride is known. This reaction is represented by the following reaction formula (1).

2RSH＋Scl ₂ →RS ₃ R＋2Hcl ……(1) However, sulfur dichloride has an equilibrium relationship with sulfur monochloride as shown in reaction formula (2) below: 2Scl ₂ S ₂ Cl ₂ +Cl ₂ ……(2) There is always about 10% sulfur monochloride in sulfur dichloride. Therefore, this sulfur monochloride also reacts with the alkyl mercaptan, as shown in reaction formula (3) below, to produce dialkyl tetrasulfide.

2RSH+S ₂ cl ₂ →RS ₄ R+2Hcl...(3) Therefore, the dialkyl trisulfide obtained by this method also contains a considerable amount of dialkyl tetrasulfide, which is highly corrosive to copper plates, and these are separated and purified. As mentioned above, it is difficult to do so, and therefore it is difficult to adopt it as an industrial manufacturing method.

The present inventors have invented a method for selectively producing dialkyl trisulfides by controlling the ratio of alkyl mercaptan to sulfur,
Although a patent application was filed at the same time as this application, this method requires a large amount of energy to distill the unreacted raw material alkyl mercaptans and the reaction solution under reduced pressure, and the resulting dialkyl trisulfide contains trace amounts of However, it may contain polysulfides such as dialkyltetrasulfides and may exhibit corrosive properties to copper plates.

An object of the present invention is to provide a method for producing dialkyl trisulfides with improved corrosion resistance to copper plates.

As a result of intensive research to achieve the above object, the present inventors have discovered that by treating dialkyl trisulfides obtained by the reaction of alkyl mercaptan with sulfur with a certain sulfur compound, the dialkyl trisulfides can be The present invention was completed based on the discovery that the corrosion resistance of copper plates was significantly improved. The present invention is characterized in that the corrosion resistance of copper plates is improved by mixing dialkyl polysulfides obtained by reacting alkyl mercaptans with sulfur and sodium sulfide or one of the compounds. This is a method for producing dialkyl trisulfide.

In the present invention, dialkyl polysulfides are a combination of alkyl mercaptans consisting of a linear or side chain alkyl group having 3 to 18 carbon atoms, such as tertiary butyl mercaptan, tertiary nonyl mercaptan, tertiary dodecyl mercaptan, etc., and sulfur. dialkyl disulfides, dialkyl trisulfides, dialkyl tetrasulfides, dialkyl pentasulfides obtained in the presence of alkaline earth metal oxides such as magnesium oxide, calcium oxide, barium oxide as catalysts;
It is a mixture of dialkyl hexasulfide, dialkylheptasulfide, etc. Further, the esfine compounds include triphenylphosphine, trilauryltrithiophosphine, and the like.

In the present invention, dialkyl polysulfides obtained by reacting alkyl mercaptans with sulfur using an alkaline earth metal oxide as a catalyst are preferably reacted with 0.7 to 1.5 grams of sulfur per mole of the alkyl mercaptan. The resulting dialkyl polysulfide containing dialkyl trisulfide as a main component and a sodium sulfide aqueous solution or a solvent solution of a phosphine compound such as triphenylphosphine or trilauryl trithiophosphine are heated at 30 to 80°C. By mixing for 1 to 5 hours at a temperature of Can be done. The reason for the improvement in corrosion resistance of copper plates is that high polysulfides such as dialkyltetrasulfide and dialkylpentasulfide react with sodium sulfide or phosphine compounds, and dialkyltrisulfide and sodium polysulfide or triphenylphosphine sulfide react with each other. It is assumed that this is due to the production of trilauryltrithiophosphine sulfide, trilauryltrithiophosphin sulfide, and the like.

The dialkyl trisulfides treated by the method of the present invention are ranked 1a in terms of corrosion resistance to copper plates at 100° C. for 3 hours according to JISK-2513 "Petroleum Products Copper Plate Corrosion Test Method."

The present invention provides a method for producing a dialkyl trisulfide that has significantly improved corrosion resistance to copper plates through simple operations, and has extremely great industrial significance.

The present invention will be explained in more detail below with reference to Examples. However, the present invention is not limited to the following examples.

Example 1 480 gr (3 moles) of tertiarynonyl mercaptan, 96 gr (3 g atoms) of crystalline sulfur and magnesium oxide powder as catalyst in a stirred reaction vessel.
Add 8.4gr and heat externally to 70℃ while stirring.
The temperature was raised to . When the temperature was maintained at 70°C and stirring was continued, the generation of hydrogen sulfide stopped after about 30 minutes. After filtering the reaction solution to separate the catalyst, it was heated under reduced pressure to distill off the unreacted tertiary nonyl mercaptan, by-product hydrogen sulfide, and volatile components remaining in the reaction solution, producing 504g of pale yellow and transparent tank residue. Obtained.
The resulting can residue was subjected to liquid chromatography (column:
Fine par SIL18, carrier: isopropanol/methanol: 5/95v/v, flow rate: 0.7ml/
min, detector, UV abs at 226nm), ditertiarynonyl disulfide 3.2%;
The contents were 84.5% ditertiarynonyl trisulfide, 8.3% ditertiarynonyl tetrasulfide, and 4.0% ditertiarynonyl pentasulfide.
Add 5% of this can residual liquid to spindle oil and use JISK
-2513 "Petroleum Products Copper Plate Corrosion Test Method" When conducting a copper plate corrosion test, the judgment at 100℃ for 3 hours was as follows.
It was 2a. 100g of the remaining liquid from the tank and an aqueous sodium sulfide solution prepared by dissolving 50g of sodium sulfide nonahydrate in 50ml of water were stirred and mixed at a temperature of 60 to 70°C for 3 hours. This mixture was separated by decantation, and 100 ml of 10% brine was added to the oil layer and stirred. The oil layer was separated by decantation again and the resulting oil layer was dehydrated with anhydrous sodium sulfate. Analysis of the obtained oil by liquid chromatography revealed that jitter
The content was 3.5% for syalinonyl disulfide and 96.5% for ditertyalinonyl trisulfide, and the peak of diterthyalinonyl tetrasulfide had disappeared. A copper plate corrosion test (100°C, 3 hours) in which 5% of the oil was added to spindle oil gave a rating of 1a.

Example 2 Tertiarynonyl mercaptan 480gr (3 moles),
The same equipment as in Example 1 was used except that 76.8gr (2.4g atom) of powdered sulfur and 8.4gr of magnesium oxide powder were used, and the process was carried out in the same manner as in Example 1 to obtain 405gr of pale yellow and transparent can residue. Ta.

The results of liquid chromatography analysis of the residual liquid from the can were 3.2% ditertiarynonyl disulfide, 96.3% ditertiarynonyl trisulfide, and 0.5% ditertiarynonyl tetrasulfide. Addition of 5% spindle oil, 100℃, 3
The judgment for time) was 1b.

100gr of the remaining liquid from the can and triphenylphosphine
A solution of 1.0gr dissolved in 10ml of acetone and a solution of 40 to 50
The mixture was stirred and mixed for 3 hours at a temperature of .degree. This mixed solution was then heat-treated under reduced pressure to distill off acetone and obtain an oily substance.

As a result of liquid chromatographic analysis of the oily substance, the peak of ditertiarynonyltetrasulfide had disappeared, and the copper plate corrosion test performed by adding 5% of the oil to spindle oil gave it a rating of 1a.

Example 3 480 g (3 moles) of tertiarynonyl mercaptan,
Except for using 124.8 g (3.9 mol) of powdered sulfur and 8.4 g of magnesium oxide powder, the same equipment as in Example 1 was used and the same treatment as in Example 1 was carried out to obtain 540 g of pale yellow and transparent can residue. . Almost no tertiarynonyl mercaptan remained in the reaction solution before treatment.

The results of liquid chromatography analysis of the residual liquid from the can were 55.7% ditertiarynonyl trisulfide, 32.3% ditertiarynonyl tetrasulfide, 9.8% ditertiarynonyl pentasulfide, and ditertiarynonyl hexasulfide. Copper plate corrosion test (spindle oil, 5% added, 100℃3
The judgment for time) was 4c.

100g of the remaining liquid from the can and 80g of sodium sulfide nonahydrate.
60-70 ml of sodium sulfide aqueous solution dissolved in 80ml
The mixture was stirred and mixed for 3 hours at a temperature of .degree. After 100 ml of 10% saline was added to the oil layer separated by decantation from this mixture and stirred, the oil layer separated by decantation again was dehydrated with anhydrous sodium sulfate. Analysis of the obtained oil by liquid chromatography revealed that it contained 99% or more of di-tertiary nonyl triphide, di-tertiary nonyl tetrasulfide, di-tertiary nonyl pentasulfide, and di-tertiary nonyl hexasulfide. The fied peak had disappeared.

A copper plate corrosion test (100°C for 3 hours) in which 5% of the oil was added to spindle oil gave a rating of 1a.

Claims (1)

[Claims] 1. A dialkyl polysulfide obtained by reacting an alkyl mercaptan with sulfur;
A method for producing dialkyl trisulfides, which improves the corrosion resistance of copper plates by mixing them with sodium sulfide or one of phosphine compounds. 2. The method according to claim 1, wherein the alkyl mercaptan is one type of mercaptan consisting of an alkyl group having 3 to 18 carbon atoms. 3. The method according to claim 1, wherein the catalyst for dialkyl polysulfide synthesis is one selected from alkaline earth metal oxides. 4. The method according to claim 1, wherein the phosphine compound is either triphenylphosphine or trilauryltrithiophosphine. 5 For 1 mole of alkyl mercaptan, sulfur
Claim 1, in which a dialkyl polysulfide obtained by reacting 0.7 to 1.5 gram atoms and an aqueous sodium sulfide solution or a solvent solution of a phosphine compound are mixed at a temperature of 30 to 80°C for 1 to 5 hours. The method described in Section 1.