JPS641464B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention focuses on polythioalkyldimethylcaptans, which have recently been used on an industrial scale as chain transfer agents, various sealants, and raw materials for adhesives because they exhibit flexible properties unique to sulfur-containing compounds. More specifically, it relates to an improved production method for producing polythioalkylene dimercaptans used in the above applications in high yield and high purity by mercaptizing mono- or dihydroxypoly(mono)thioachilenes with thiourea. Regarding how to. "Prior art" Mono- or dihydroxypoly(mono)thioalkylenes (hereinafter abbreviated as HSAs) are reacted with thiourea and hydrogen chloride to produce the following A method for producing polythioalkylene dimercaptans (hereinafter abbreviated as SADMs) by forming a thiuronium salt and then decomposing the thiuronium salt with an alkaline substance is well known. However, this method has traditionally had unavoidable drawbacks such as low yield and low purity of SADMs. "Problems to be Solved by the Invention" The present inventors have solved the above problems and achieved high yield.
As a result of various studies to obtain high-purity SADMs,
We have arrived at the present invention. "Means for Solving the Problems" The first method of the present invention is aimed at the alkali decomposition step of the thiuronium salt in the above-mentioned manufacturing process.
This is an improved production method for SADMs characterized by the coexistence of SADMs and metal salts of the same type or different types of SADMs. The same kind of SADM is used in the alkali decomposition process of the thiuronium salt.
This is an improved method for producing SADMs characterized by the coexistence of metal salts of SADMs. In carrying out the method of the present invention, HSAs used as starting materials have the following general formula [1] or [2]
It is shown in HO(RS)nH...[1] HO(RS)mROH...[2] [Here, R represents an alkylene group having 2 or 3 carbon atoms, and n and m represent natural numbers of 1 to 4. ] Specific examples of these HSAs include 2-mercaptoethanol (HOCH ₂ CH ₂ SH), 1-hydroxy-5-mercapto-3-thiapentane (HOCH ₂ CH ₂ SCH ₂ CH ₂ SH), and 1-hydroxy-8- Mercapto-3,6-dithiaoctane
(HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SH), 1-hydroxy-11-mercapto-3,6,9-
Trithiaundecane (HO(CH ₂ CH ₂ S) ₄ H), Thiodiglycol
(HOCH ₂ CH ₂ SCH ₂ CH ₂ OH), 1,8-dihydroxy-3,6-dithiaoctane (HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH), 1,11
-dihydroxy-3,6,9-trithiaundecane (HO(CH ₂ CH ₂ S) ₃ CH ₂ CH ₂ OH), 1,14-dihydroxy-3,6,9,12-tetrathiatetradecane
(HO(CH ₂ CH ₂ S) ₄ CH ₂ CH ₂ OH), etc. In addition to 2-methyl-2-mercaptoethanol and thiodipropylene glycol, some or all of the ethylene groups in the above compound group are propylene groups. Examples include similar compounds substituted with . When producing thiuronium salts as described above, HSAs and thiourea are generally reacted in the presence of a mineral acid. It is usually preferable to use thiourea and mineral acid in an amount equal to or more than the equivalent mole relative to the hydroxyl group of the HSA, but if more than twice the mole or equivalent is used, post-reaction treatment should be taken into consideration. It is not desirable. As the mineral acid, hydrochloric acid or sulfuric acid is preferable. Since this thiuronium salt production reaction is accompanied by heat generation, usually HSAs or thiourea is added continuously or intermittently in small amounts to keep the reaction temperature at 50 to 100°C. It is preferable to control it so that Furthermore, in order to carry out this reaction smoothly, it is generally carried out in an aqueous medium, and the concentration of all reaction raw materials in the aqueous solution is preferably 10 to 50% by weight. Next, this aqueous solution is used for the generation reaction of SADMs, in other words, for the alkaline decomposition reaction of thiuronium salt. This alkaline decomposition reaction is an exothermic reaction, and it is generally preferable to add the alkaline compound to the reaction system continuously or intermittently, and to maintain the reaction temperature between 30 and 80°C.
As the alkaline compound used in this alkaline decomposition reaction, an alkali metal hydroxide is generally preferred and the same holds true when carrying out the method of the present invention. Sodium hydroxide and potassium hydroxide are preferable as the alkaline compound, and the amount used is preferably at least one equivalent mole and at most two times the mole based on all the thiuronium groups present in the system after thiuronium salt formation. Needless to say, if any acid remains, an additional alkaline compound is required to neutralize it. On the other hand, when a thiuronium salt is subjected to alkaline decomposition according to the method of the present invention, it is essential to coexist in the reaction system a metal salt of the same or different type of SADM to be produced. This coexisting SADM metal salt is not particularly limited, but considering the separation and purification after the production of the target SADM,
Those of the same type as SADMs are preferable, and as the salt thereof, alkali metal salts are preferable. This coexistence
The amount of SADM metal salt coexisting is preferably 10 to 50% by weight based on the thiuronium salt subjected to alkaline decomposition.If the amount used is less than the lower limit, the effect will not be noticeable, and if the amount is more than 50% by weight, it is not necessary. . On the other hand, in producing a thiuronium salt according to the second method of the present invention, in addition to the above three reaction materials, a thiuronium salt of the same type or different type as the produced thiuronium salt is allowed to coexist. This will lead to more favorable results. There are no particular restrictions on the coexisting thiuronium salt, but
Considering the separation and purification of SADMs after their generation, they can be derived from HSAs. In other words, it is preferable that the thiuronium salt is the same as the thiuronium salt that is originally produced. There is no particular limitation on the method of addition to the reaction system for coexistence, but for example,
A method of adding thiourea to a mixture of HSAs, a mineral acid, and a thiuronium salt coexisting as described above;
Examples include a method in which HSAs and mineral acids are preferably added separately. The amount of coexistence is preferably 10 to 50% by weight based on the starting HSA, and if it is less than the lower limit, the coexistence effect will not be significant, and if the amount exceeds the upper limit, the efficiency of the reaction for producing the thiuronium salt will be significantly reduced, so both are preferable. do not have. If the thiuronium salt production reaction is carried out under the above reaction conditions, the desired salt can usually be obtained in 5 to 10 hours, but if thiuronium salts other than those involved in the reaction are coexisting as described above, even more favorable results can be obtained. is obtained. That is, the desired thiuronium salt is produced in high yield in the aqueous solution as described above. As mentioned above, if the method of the present invention is carried out, the metal salts of the coexisting SADMs will remain in the reaction system, so in order to recover them, the coexisting salts should be neutralized again with the mineral acid described above. good. In addition, even if an alkaline compound is used in an amount greater than that required for decomposing the thiuronium salt in the original alkaline decomposition, some of the HSDMs intended to be produced also exist as metal salts. Salts should also be neutralized using mineral acids and recovered as HSDMs. Thus, if the method of the present invention is carried out, HSDMs can be obtained in a higher yield than in the general method described above, but since the HSDMs are separated from the aqueous solution as described above, it is separated and mixed with water or water. Highly pure HSDMs can be easily obtained by washing with another solvent and purifying by a known purification method such as distillation. "Example" The method of the present invention will be described in detail below with reference to Examples and Comparative Examples, but the method is not limited thereto. Note that the parts described below indicate parts by weight. Example 1 (Thiuronium chloride reaction) 31.5% hydrochloric acid was placed in a 4-necked flask with contents 1 equipped with a stirrer, a thermometer, an Allene condenser, and a dropping device.
145 parts of bis(2-hydroxyethyl) sulfide was gradually added dropwise to a slightly heated homogeneous solution containing 298 parts of thiourea and 194 parts of thiourea, and after completion of the dropwise addition, stirring was continued at 100°C for 4 hours. Thereafter, it was cooled and the reaction solution was divided into approximately three equal parts. These are called reaction solutions (A), (B), and (C). The above reaction solution (A) was returned to the reactor and the above thiuronium salt reaction was repeated in the presence of the thiuronium salt. After cooling, divide the reaction solution into two equal parts and divide these into two equal parts.
(D) and (E). (Mercaptization reaction) Add 64 parts of sodium salt of dimercapto diethyl sulfide to the same reactor as above reaction solution (B) and dissolve completely, then slowly add 413 parts of 50% aqueous sodium hydroxide solution. It was added dropwise and reacted at 60°C for 30 minutes. After cooling, excess alkali was neutralized with hydrochloric acid, 84 parts of xylene was added, and the organic layer was separated. This organic layer was separated and xylene was removed by distillation under reduced pressure, yielding 154 parts of the desired dimercapto diethyl sulfide. The yield of newly produced dimethylcaptodiethyl sulfide after subtracting the amount added at the beginning is 82% and the purity is 85% based on the raw material bis(2-hydroxyethyl) sulfide.
It was hot. Comparative Example 1 The reaction solution (C) described in Example 1 was placed in a similar reactor, and the method described in Example 1 was repeated without adding the sodium salt of dimercapto diethyl sulfide. The yield was 69% and the purity was 71%. Example 2 The reaction solution (D) described in Example 1 was placed in a similar reactor, and 64 parts of sodium salt of dimercapto diethyl sulfide was added and dissolved, followed by 413 parts of a 50% aqueous sodium hydroxide solution. was slowly added dropwise and allowed to react for 30 minutes while keeping the temperature below 60°C.
(Mercaptation reaction) When the method described in (Mercaptization reaction) was repeated, a new raw material bis(2
-Hydroxyethyl) sulfide yield is
The purity was 92% and the purity was 95%. Example 3 Into the same reaction apparatus as in Example 1, 74 parts of a 31.5% aqueous hydrochloric acid solution and 49 parts of thiourea were charged to form a homogeneous solution. To this solution was added 118 parts of 1-hydroxy-8-mercapto-3,6-dithiaoctane, and a thiuronium salt reaction was carried out under the same conditions as in Example 1. After cooling, divide the reaction solution into two equal parts and divide these into two equal parts.
(F) and (G). This reaction solution (F) was placed in a similar reactor, and raw materials were charged under the same conditions as above to perform the thiuronium chloride reaction again. Next, potassium salt of 1,8-dimethylcapto-3,6-dithiaoctane34 was added to the reaction solution.
After adding 217 parts of a 30% potassium hydroxide aqueous solution to the mixture to form a homogeneous solution, 217 parts of a 30% potassium hydroxide aqueous solution was slowly added dropwise, and the mixture was reacted at a temperature of 60° C. or lower for 1 hour. Thereafter, the mixture was treated in the same manner as described in Example 1 to obtain 224 parts of 1,8-dimethylcapto-3,6-dithiaoctane.
The yield after subtracting the added amount is 95%, and the purity is
It was 92%. Comparative Example 2 The reaction solution (G) prepared in Example 3 was placed in a similar reactor, and 72 parts of a 30% potassium hydroxide aqueous solution was added without adding the metal salt of 1,8-dimercapto-3,6-dithiaoctane. The mercaptation reaction and post-reaction post-treatment described in Example 3 were repeated using the following. The amount of 1,8-dimercapto-3,6-dithiaoctane obtained was 124 parts. The yield was 70% and the purity was 68%. Example 4 and Comparative Example 3 In a reactor similar to that used in Example 1, 149 parts of 31.5% hydrochloric acid and 97 parts of thiourea were charged to form a homogeneous solution. To this, 1,11-dihydroxy-3,6,9-
Trithiaundecane was added, and the thiuronium salt reaction described in Example 1 was carried out. This reaction solution was divided into two equal parts, which were designated as reaction solutions (H) and (J). The reaction solution (H) contains 1,11-dimercapto-3,6,
Example 1 was prepared by adding 44 parts of sodium salt of 9-trithiaundecane (Example 4), not adding it to the reaction solution (J) (Comparative Example 3), and using 62 parts of a 50% aqueous sodium hydroxide solution. Mercaptization reaction) The method described above was repeated, and the results obtained are shown in Table 1.

[Table] Example 5 and Comparative Example 4 31.5% in the same reactor as used in Example 1
149 parts of an aqueous hydrochloric acid solution and 97 parts of thiourea were charged to form a homogeneous solution. Then 110 parts of 2-mercapto-1-methylethyl alcohol were slowly added dropwise to this solution and the method described in Example 1 (thiuronium chloride reaction) was repeated. After cooling, this reaction solution was divided into two equal parts, which were designated as reaction solutions (K) and (L). The reaction solution (K) was returned to the above-mentioned reactor, and the above-mentioned thiuronium chloride reaction was repeated. Add 1,2
-Add 39 parts of sodium salt of dimercapto-1-methylethane to 186% 50% sodium hydroxide aqueous solution
The mercaptation reaction described in Example 1 was repeated using (Example 5) On the other hand, reaction solution (L) and 50%
The mercaptation reaction described in Example 1 was repeated using only 62 parts of aqueous sodium hydroxide solution. (Comparative Example 4) Table 2 shows the results for the obtained 1,2-dimercapto-1-methylethane.

[Table] Yield for alcohol In the method of the present invention, both the purity and yield of the target compound are improved. It is shown in Table 3.

[Table] ○: Addition ×: No addition ``Effects of the invention'' The method of the present invention makes it possible to produce polythioalkylene dimercaptans from mono- or dihydroxypoly(mono)thioalkylenes in high yield and with high purity. I can do it.

Claims (1)

[Claims] 1 Represented by the following general formula [1] or [2]. HO(RS)nH...[1] HO(RS)mROH...[2] [Here, R represents an alkylene group having 2 or 3 carbon atoms, and n and m represent natural numbers from 1 to 4] Sulfur-containing compound is reacted with thiourea and a mineral acid to form a thiuronium salt, and then the thiuronium salt is decomposed using an alkaline compound to complete the reaction. A method for producing polythioalkylene dimercaptans represented by the following general formula [3] or [4], which comprises coexisting a metal salt of a rangemercaptan. HS(RS)nH...[3] HS(RS)mRSH...[4] [Here, for R, n, and m, use the general formula [1]
and [2]. 2 It is represented by the following general formula [1] or [2]. HS(RS)nH...[1] HS(RS)mROH...[2] [Here, R represents an alkylene group having 2 or 3 carbon atoms, and n and m represent natural numbers from 1 to 4] Sulfur-containing compound is reacted with thiourea and a mineral acid to form a thiuronium salt, and then the thiuronium salt is decomposed using an alkaline compound to complete the reaction. During the production step of the thiuronium salt, thiuronium salts of the same type as the thiuronium salt are used. It is represented by the following general formula [3] or [4], characterized in that it coexists with the thiuronium salt, and in the decomposition step of the thiuronium salt, a metal salt of the same type of polythioalkylene dimercarptane as the decomposition product coexists. A method for producing polythioalkylene dimercaptans. HS(RS)nH...[3] HS(RS)mRSH...[4] [Here, for R, n, and m, use the general formula [1]
and [2].