JPS6033398B2 - Method for producing organotin compounds - Google Patents

Description

Detailed Description of the Invention This application is based on Japanese Patent No. 124675y (Japanese Patent Publication No. 59-21871
Pertaining to an additional application for the Publication No.

The present invention relates to a method for producing a specific class of organotin compounds.

The present invention further relates to a process for the preparation of organotin derivatives of mercaptoalcohol esters which offers advantages in relation to known processes for preparing organotin compounds of this type. US Pat. No. 2,870,182 discloses the general formula: RnSnA4m
(wherein R represents one of a particular group of hydrocarbon groups, n is 1, 2 or 3, and A is a hydrogen atom obtained by removing a hydrogen atom from the -SH group of the mercaptoalcohol ester) (representing the resulting residue).

The patent specification further states that the compound corresponding to the above formula is prepared by first reacting a mercapto alcohol with a carboxylic acid in the presence of a suitable esterification catalyst, and subsequently converting the resulting ester to an organotin halide, an organotin oxide or an organostannic acid. It states that it can be produced by reacting with (organostannolcacid). However, this method of preparation is less desirable for a number of reasons. First, the formation of mercaptoalcohol esters is an equilibrium reaction that almost always requires an acidic catalyst and removal of water during the reaction to obtain a useful yield of the desired product within a reasonable period of time. Such acid catalysts end up promoting a number of undesirable side reactions, including the polymerization of mercapto alcohols. Although the polymers may contain end groups that are subsequently reacted with organotin compounds, the reaction products are far less effective than the desired monomeric ester derivatives in many applications, including the stabilization of vinyl chloride polymers. . Another undesirable feature of the prior art method is the necessity for water removal during the preparation of the ester and during the reaction of the ester with the organotin compound. Removal of water requires heating, which not only increases process costs due to additional energy input, but also results in large amounts of undesirable creations due to side reactions. Furthermore, it is common for some mercaptoalcohol to be co-distilled with water. It has now been discovered that the disadvantages inherent in the conventional process can be avoided if the mercapto alcohol is first reacted with an organotin compound and then esterified. Reactions of organotin halides and organotin oxides with both mercaptans and alcohols have been reported in the chemical literature. It is therefore expected to obtain a mixture of products containing tin-oxygen and tin-sulfur bonds.
Surprisingly, under the conditions described below, only the mercapto (-SH) moiety of the mercapto alcohol reacts with the organotin compound. The hydroxyl moiety in the molecule remains available for subsequent esterification with a carboxylic acid. According to the present invention, the following steps, i.e., the monoorganic /tin trihalide,
said monoorganic/tin trihalide' of a base selected from the group consisting of ammonium hydroxide, alkali metal hydroxides and alkaline earth metal hydroxides is reacted with an aqueous solution containing a stoichiometric amount; The ratio between the number of equivalents of the base and the number of moles of the monoorganotin trihalide is 1:1; -Add mercaptoprobanol; '3
- Adding an alkali metal sulfide or alkali metal disulfide to the reaction product of step (2), the number of moles of sulfide or disulfide being equal to the number of moles of tin present in said reaction product; Separate the phases;
a carboxylic acid of the formula: R'COOR'', where R' is as defined below, or {6} isolating the desired monoorganotin compound; more essentially the following general formula: or (wherein R and R' are the group consisting of alkyl, cycloalkyl, aralkyl, aryl and alkaryl groups containing 1 to 2 carbon atoms) individually selected from m
is 2 or 3) is provided.

The first step of the present process for producing monoorganotin derivatives of mercaptoalcohol esters consists of reacting the corresponding monoorganotin trihalide of the following formula: RS 3 with an aqueous solution containing a stoichiometric amount of base.

All of the base can be added first to react with the organotin halide. Alternatively, the majority of the base is added first, usually about 90% of the total, and the remainder is added subsequent to the addition of the alkali metal sulfide. As described in the above specification, the symbol x in the above formula represents chlorine, bromine or iodine, and R is an alkyl group, cycloalkyl group, aryl group, alkaryl group or aralkyl group containing 1 to 20 carbon atoms. represents a group.

When R is an alkyl group, it can be a methyl group, an ethyl group, an n-propyl group, an isopropyl group or a higher homolog containing two increments of carbon atoms. Suitable cycloalkyl groups include, for example, cyclopropyl, cyclobutyl, cyclohexyl and cyclooctyl. When R is an aryl group, it is preferably a phenyl group, but it can also represent a naphthyl group, anthracenyl group or biphenyl group. Suitable aralkyl groups include
Examples include the penzyl group and 8-phenylethyl. When R is an alkaryl group, for example one of the isomeric tolyl, xylyl or other alkyl-substituted phenyl groups.
can be. The base used can be ammonium hydroxide, an alkali metal hydroxide such as sodium hydroxide or an alkali metal hydroxide such as calcium hydroxide.

The term "stoichiometric" is defined as for each mole of monoorganotin trihalide - 1 mole of a functional base such as sodium hydroxide or 0.5 mole of a difunctional base such as calcium hydroxide. .

The reaction between the halogen atoms of organotin halides and bases is rapid at room temperature and is often highly exothermic.

The addition of organotin halide should therefore be gradual, simultaneously heating and cooling the reaction mixture to prevent local overheating. It may be desirable to continue heating the reaction mixture after all of the organotin halide has been added to improve heat transfer and increase the cooling temperature. The resulting solution of organotin hydroxyhalide is then reacted with the desired mercapto alcohol. This reaction rate is much slower than the rate at which the raw organotin halide reacts with the base. Therefore, to complete the reaction in a reasonable period of time, usually 5 to 60 minutes, the reaction mixture is
It is desirable to maintain the The number of moles of mercapto alcohol added is equal to the number of equivalents of base used in the first step of the method. The most easily available mercapto alcohol is 2
monomercaptoethanol and 3-mercaptopropanol. These compounds are therefore preferred for use in the present method. Other known mercapto alcohols such as 4-mercapto-1-butanol are equally suitable. When the reaction between the organotin compound and the mercapto alcohol is complete, and the desired product contains two sulfur atoms per molecule, the resulting mixture is diluted with 1 mole of tin for each mole of tin present in the reaction mixture. Combines with alkali metal sulfides.

Equimolar amounts of alkali metal disulfide are used when the product contains 3 sulfur atoms. The disulfy Z
The compound can be formed by reacting equimolar amounts of an alkali metal sulfide and elemental sulfur. Preferably, the sulfide or disulfide is added gradually to the organotin component. This is because it can be an exothermic reaction. The sulfides or disulfides mentioned above can be added as solids or as aqueous solutions.
Any base not added during the initial hydrolysis of the halide is added at this stage. Following completion of the addition of the sulfide, the desired carboxylic acid or alcohol containing one to two needle carbon atoms of the formula: RCOOH, where R' is as defined above, is added. The following formula: R'
The mercaptoalcohol retentate is esterified by adding an equimolar amount of an ester of the carbosic acid COOR'', where R' and R'' are as defined above.

Suitable acids contain from 2 to 20 carbon atoms, and the hydrocarbon group is an alkyl, cycloalkyl, aryl, aralkyl, or alkaryl group as described above for the hydrocarbon portion of the organotin halide reagent. . R' is a halogen, a hydroxyl group, an alkoxy group, and a nitro group (
may contain one or more substituents such as 02). In contrast to conventional esterification reactions, no superstoichiometric excess of carboxylic acid is required, nor is it necessary to add a catalyst. Octanoic acid, also known as caprylic acid, is preferred. This is because the products prepared with this acid do not exhibit the unpleasant odors characteristic of organotin compounds of this type. If an ester of the acid is used, it is preferred that the alcohol residue contains 1 to 4 carbon atoms to facilitate removal of the alcohol by distillation during the transesterification reaction. When the organotin compound of interest is used as a stabilizer for halogenated polymers such as polypynyl chloride, the ester of the following formula: R'COOH'', where R' and R'' are as defined above. It may be desirable to use a high molecular weight alcohol containing from 12 to 20 carbon atoms as the alcohol component of the alcohol component.
In this case the alcohol R''OH is not removed during transesterification, but rather is isolated together with the desired organotin product. Serves as an auxiliary agent.Once the carboxylic acid or ester has been added, the aqueous phase of the reaction mixture is removed and discarded.Following removal of the aqueous phase,
The reaction mixture is heated to 100-180° C. to carry out the esterification reaction or transesterification reaction. The by-product is water or about 12
If the alcohol is volatile and boils below 0q0, by-products are continuously removed during the reaction using a suitable distillation device. To minimize overheating and consequent decomposition of the product, the last portion of the water is preferably removed under reduced pressure, usually equal to 10 to 10 Hg'. Once all water or alcohol has been removed, the desired liquid organotin compound remains in the reaction vessel. It may be necessary to filter the product to remove small amounts of solid material. The products obtained using this method are useful in the same applications as other mono- and diorganotin compounds containing tin-sulfur bonds.

The compounds of this invention are particularly effective as heat stabilizers for vinyl chloride polymers and other high molecular weight halogen-containing polymers.
It is customary to use the compounds for this purpose in concentrations of 0.1 to 10% by weight. Organotin derivatives of mercaptoalcohol esters can also be used as antioxidants for various substances. Preferred embodiments of the method of the invention are illustrated by the following examples, but these examples should not be construed as limiting the scope of the invention. Example 1 Production of monobutyltin-2-mercaptoethylcaprylate sulfide A reaction vessel was charged with 141.1 units (0.5 mol) of monobutyltin trichloride and 150 cc of water.

To the resulting solution is gradually added 29.09 (0.5 mol) ammonium hydroxide in a proportion sufficient to maintain the temperature of the reaction mixture below 6000 or 60 qo without externally cooling the reactor. Following the completion of the ammonium hydroxide addition, the reaction mixture was heated for 5 minutes, at which time 39.85 g (0.5 mol) of 21-mercaptoethanol was added to the reactor contents and the contents were allowed to cool. Heat to 6000℃ for 30 minutes. The reaction mixture was then heated to 40 pm.
65.0 mol (0.5 mol) of solid sodium sulfide is added at such a rate that the temperature of the reaction mixture does not exceed 6000 ℃. Once the sodium sulfide addition is complete, the reaction mixture is then heated for 2 minutes, maintaining the temperature at 60°C using external heating. Then 79.12 evening (
0.5 mol) of methyl caprylate is added to the reaction mixture and the contents are stirred for 10 minutes after which time the aqueous phase of the reaction mixture is removed and discarded. The organic phase is heated to 14,000 ℃ under a nitrogen atmosphere using a distillation apparatus until the evolution of methanol has stopped. The reaction mixture is then cooled and filtered to yield relatively pure monobutyltin-2-mercaptoethyl caprylate sulfide. This compound does not exhibit the unpleasant odor characteristics of monoorganotin or diorganotin derivatives of mercaptoethanol esters. A similar compound using an oleic acid ester of 2-mercaptoethanol in place of the n-octanoic acid ester has an unpleasant odor. This odor difference is also true for the corresponding methyltin derivatives. These compounds are prepared by reacting methyltin trichloride, a substitute for the corresponding butyltin morolide. Additional related original invention (Patent No. 124675y (Japanese Patent Publication No. 59-2187)
(No. 1 Publication), ``The next step, i.e., the following formula: RS 3 (in the formula, R is as defined below and Tin trihalide, diorganotin dihalide of the following formula: R2SnX2 (wherein R is as defined below and and an aqueous solution containing a base selected from the group consisting of alkali metal alkoxides, alkali metal alkoxides, alkali metal alkoxides, and ammonium hydroxide, in which the number of equivalents of the base and the organotin halide are The ratio of the number of moles of halogen present from the beginning is n-2:n, respectively.
and ■ n-2 moles of 2- to the resulting mixture;
Add captoethanol or 3-mercaptopropanol: '31 To the reaction product of step and p is 2), the number of moles of sulfide or disulfide being equal to 0.5 times the number of moles of tin present in the reaction product; 2 moles of a carboxylic acid of the formula: R'COO, where R' is as defined below, or a carboxylic acid of the formula: R'CO
OR'', where R' is as defined below, and R'' is an alkyl group containing 1 to 20 carbon atoms.
ester of the following general formula: or (wherein R and R are 1 to 2); individually selected from the group consisting of alkyl groups, cycloalkyl groups, aralkyl groups, aryl groups and alkaryl groups containing a carbon atom, m
is 2 or 3 and p is 1 or 2), the present invention relates to a process for producing an organotin compound of RSnX3 in step 1', a monoorganotin trihalide of RSn The monoorganotin trihalide of RS sail 3 is used instead of the equimolar mixture of .

Claims (1)

[Scope of Claims] 1. The following steps: (1) A monomer of the following formula: RSnX_3 (wherein R is as defined below, and X is a halogen selected from the group consisting of chlorine, bromine, and iodine); reacting an organotin trihalide with an aqueous solution containing a stoichiometric amount based on said monoorganotin trihalide of a base selected from the group consisting of ammonium hydroxide, alkali metal hydroxides and alkaline earth metal hydroxides; In this case, the ratio between the number of equivalents of the base and the number of moles of monoorganotin trihalide is 1:1; (2) an equimolar amount of 2-mercaptoethanol is added to the resulting mixture based on the monoorganotin trihalide; Or add 3-mercaptopropanol; (3)
Adding an alkali metal sulfide or alkali metal disulfide to the reaction product of step (2), the number of moles of sulfide or disulfide being equal to the number of moles of tin present in said reaction product; (4) reaction mixture; (5) The product thus obtained is dissolved in an equimolar amount, based on the monoorganotin trihalide, of the following formula: R'COOH, where R' is defined below. ) or the following formula: R'COO
R'' (wherein R' is as defined below, R'' is 1
(6) isolation of the desired organotin compound; The following general formula, which is essentially the process of individually selected from the group consisting of alkyl groups, cycloalkyl groups, aralkyl groups, aryl groups and alkaryl groups, containing m
is 2 or 3). 2. The method of claim 1, wherein R and R' are individually selected from the group consisting of alkyl groups containing from 1 to 20 carbon atoms. 3. The method according to claim 2, wherein R is a butyl group. 4. The method according to claim 1, wherein the carboxylic acid is caprylic acid or pelargonic acid. 5. The method according to claim 1, wherein m is 2. 6. The method according to claim 1, wherein X is chlorine. 7. The method according to claim 1, wherein the base reacted with the organotin halide is amnium hydroxide. 8. The method according to claim 1, wherein the alkali metal sulfide is sodium sulfide. 9. The method according to claim 1, wherein R'' contains 1 to 4 carbon atoms. 10. A patent in which the alkali metal disulfide is formed by reacting equimolar amounts of the alkali metal sulfide and elemental sulfur. 11. The method according to claim 1. 11. Reacting the product of step (3) with a carboxylic acid ester of the following formula: R'COOR'', where R' and R'' are as defined above. The following formula was formed as a by-product of: R
2. The method of claim 1, wherein the alcohol of ``OH'' is removed by distillation before isolating said organotin compound.