DE19833914C2 - Process for the preparation of thiuram disulfides - Google Patents

Description

The invention relates to a process for the preparation of an aliphatic, arali phatic and / or aromatic hydrocarbon radicals substituted thiuram disulfide by reacting one or more appropriately substituted amines with Carbon disulfide in water in the presence of oxygen and a metal containing catalyst.

Thiuram disulfides form a class of substances that are used in plant protection as fungicides, as well as in the rubber industry as a vulcanization accelerator great economic Has gained importance. DE 32 43 141 describes the use of thiuramdi sulfides and the like a. described as a vulcanization accelerator. Therefore there is a Interest in synthetic processes for the thiuram disulfides that are as possible in engineering are cheap and easy to carry out.

In Ullmann's Encyclopedia of Technical Chemistry, Vol. 9, A9, VCH Verlag Gesellschaft Weinheim, 1987, pp. 1 ff. become the oxides common in technology tion process described. In general, chlorine, Sodium hypochlorite or hydrogen peroxide used.

DE 31 05 622 and DE 31 05 587 describe a process for the preparation of thiuram disulfides by reaction of substituted secondary amines with carbon disulfide in a solvent and in the presence of oxygen or an oxygen containing gas and a metal-containing catalyst in the presence of a tertiary Amines or ammonia described. A disadvantage of these methods, however, is that the listed catalysts were not dissolved in the entire process Form and present as an undesirable impurity together with the product fall. This is disadvantageous for the further use of these products.

A method is already known from document DE 12 26 564, according to which a secondary alkyl, aryl or alkylarylamine with carbon disulfide in one  aqueous or non-aqueous medium by means of an oxygen-containing gas and a metal catalyst is converted to the substituted thiuram disulfide. As Catalyst is used as a carboxylated or sulfonated metal phthalocyanine finally metals from groups 8 to 10 of the periodic table before However, cobalt phthalocyanine is used. The yields are with this The process is comparatively low, at best around 25% of the Theory.

It is also known that for the oxidation of alkali metal salts substituted Dithiocarbamic acids with oxygen can use metal-containing catalysts. So is a process for dialkyl similar to the document DE 12 26 564 just mentioned dithiocarbamic acids described in DE 11 65 011. Here too carboxylated or sulfonated metal phthalocyanines, with only metals of Groups 8 to 10 of the Periodic Table of the Elements, especially cobalt and iron be used. During the process, per mole of thiuram disulfide is formed 2 moles of sodium chloride was difficult both ecologically and economically major disadvantage is.

The object of the invention was to provide a process for the preparation of thiuram disulfides from secondary amines and carbon disulfide by means of oxidation Provide oxygen under metal catalysis, which without the formation of larger Amounts of by-products lead to products that are almost free of catalyst are leftovers.

The object is achieved by a process for producing an aliphatic, Cycloaliphatic and / or aromatic hydrocarbon radicals substituted Thiuram disulfides by reacting one or more appropriately substituted ones secondary amines with carbon disulfide in water and in the presence of acid material or oxygen-containing gas and a metal-containing catalyst, thereby ge indicates that a metal complex soluble in the reaction medium as Catalyst is used, the metal being selected from groups 2 to 7, 11 and 12 of the Periodic Table of the Elements solved.  

The process according to the invention is suitable for the production of a large number of differently substituted thiuram disulfides. If a single secondary amine is used as a reactant for the reaction with carbon disulfide, thiuram disulfides are obtained which have the same substituents on the two nitrogen atoms. Symmetrically substituted secondary amines allow the synthesis of thiuram disulfides with 4 identical substituents. If a mixture of differently substituted secondary amines is used, the process conditions selected (molar ratios of the secondary amines in the feed mixture, pK _a values of the selected secondary amines, etc.) can be used to produce a tailor-made thiuram disulfide with differently substituted nitrogen atoms, or even a mixture Thiuram disulfides can be obtained.

Aliphatic secondary amines suitable for the process according to the invention are shown in for example dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, Di-sec-butylamine, di-tert-butylamine, di- (2-methylpropyl) amine, dipentylamine, di- (1-methylbutyl) amine, di- (2-methylbutyl) amine, di- (3-methylbutyl) amine, di- (1,1- dimethylpropyl) amine, di- (2,2-dimethylpropyl) amine, di- (1,2-dimethylpropyl) amine, Dihexylamine, di- (1-methylpentyl) amine, di- (2-methylpentyl) amine, di- (3- methylpentyl) amine, di (4-ethylpentyl) amine, di (1,1-dimethylbutyl) amine, di (2,2- dimethylbutyl) amine, di (3,3-dimethylbutyl) amine, di (2,3-dimethylbutyl) amine, di (1-ethylbutyl) amine, di- (2-ethylbutyl) amine, diheptylamine, di- (1-methylhexyl) amine, Di (2-methylhexyl) amine, di (3-methylhexyl) amine, di (4-methylhexyl) amine, di (5- methylhexyl) amine, di (1-ethylpentyl) amine, di (2-ethylpentyl) amine, di (3- ethylpentyl) amine, dioctylamine, di (1-methylheptyl) amine, di (2-methylheptyl) amine, Di (3-methylheptyl) amine, di (4-methylheptyl) amine, di (5-methylheptyl) amine, di (6-methylheptyl) amine, di- (3-ethylhexyl) amine, di- (2-ethylhexyl) amine, di- (3- ethylhexyl) amine, di (4-ethylhexyl) amine, methyl ethyl amine, ethyl butyl amine, Dilaurylamine, didodecylamine, ditridecylamine, dipalmitylamine, distearylamine and Dioleylamine.  

Cycloaliphatic secondary amines suitable for the process according to the invention are for example dicyclohexylamine, 4,4'-dimethyldicyclohexylamine, 3,3'-di methyldicyclohexylamine, 2,2'-dimethyldicyclohexylamine, N-methylcyclohexylamine, N-ethylcyclohexylamine, N-propylcyclohexylamine, N-isopropylcyclohexylamine, N-butylcyclohexylamine, N-sec.-butylcyclohexylamine, N-tert.-butylcyclohexylamine, N-pentylcyclohexylamine, N- (1-methylbutyl) cyclohexylamine, N- (2-methylbutyl) - cyclohexylamine, N- (3-methylbutyl) cyclohexylamine, N- (1,1-dimethylpropyl) cyclo hexylamine, N- (2,2-dimethylpropyl) cyclohexylamine, N- (1,2-dimethylpropyl) cyclo hexylamine, N-hexylcyclohexylamine, N- (1-methylpropyl) cyclohexylamine, N- (2-Me thylpentyl) cyclohexylamine, N- (3-methylpentyl) cyclohexylamine, N- (3-methylpentyl) - cyclohexylamine, N- (1,1-dimethylbutyl) cyclohexylamine, N- (2,2-dimethylbutyl) cyclo hexylamine, N- (3,3-dimethylbutyl) cyclohexylamine, N- (2,3-dimethylbutyl) cyclohexyl amine, N- (1-ethylbutyl) cyclohexylamine, N- (2-ethylbutyl) cyclohexylamine, N-heptyl cyclohexylamine, N- (1-methylhexyl) cyclohexylamine, N- (2-methylhexyl) cyclo hexylamine, N- (3-methylhexyl) cyclohexylamine, N- (1-ethylpentyl) cyclohexylamine, N- (2-ethylpentyl) cyclohexylamine, N- (3-ethylpentyl) cyclohexylamine, N-octylcyclo hexylamine, N- (1-methylpentyl) cyclohexylamine, N- (2-methylheptyl) cyclohexylamine, N- (3-methylheptyl) cyclohexylamine, N- (4-methylpentyl) cyclohexylamine, N- (5-Me thylheptyl) cyclohexylamine, N- (6-methylheptyl) cyclohexylamine, N- (1-ethylhexyl) - cyclohexylamine, N- (2-ethylhexyl) cyclohexylamine, N- (3-ethylhexyl) cyclohexylamine, N- (4-ethylhexyl) cyclohexylamine, dicyclopentylamine, N-methylcyclopentylamine, N-ethylcyclohexylamine, N-methylcyclobutylamine, N-methylcycloheptylamine and N-ethylcycloheptylamine.

Further suitable cycloaliphatic secondary amines are secondary amines in which the substituents are connected via bridging members, such as, for example, piperidine and piperidine derivatives in which there are further C ₁ -C ₅₀ substituents on the C atoms, pyrrolidine and pyrrolidine derivatives, in which there are further C ₁ -C ₅₀ substituents on the C atoms, piperazine and piperazine derivatives, in which there are further C ₁ -C ₅₀ substituents on the C atoms and other nitrogen heterocycles. C ₁ -C ₅₀ substituents for the purposes of the invention include alkyl groups such as methyl, ethyl, propyl, i-propyl, butyl, i-butyl, t.-butyl, s.-butyl, Pentyl, i-pentyl, neo-pentyl, hexyl, heptyl and octyl groups and their higher homologues, cycloalkyl such as cyclobutane, cyclopentane, cyclohexane and cyclooctane groups and their higher homologues and aryl groups such as e.g. B. understood phenyl groups, which of course in turn can be substituted.

Araliphatic secondary amines suitable for the process according to the invention are the aliphatic and cycloaliphatic amines listed, in which one or several hydrogen atoms on the hydrocarbons through aryl groups are substituted, such as dibenzylamine, di- (2-phenylethyl) - amine, di (2-phenylpropyl) amine, di (3-phenylpropyl) amine, N-methylbenzylamine, N-ethylbenzylamine, N-propylbenzylamine.

However, preferred secondary amines are 4-methylpiperazine, 4-ethylpiperazine, 4-hydroxyethylpiperazine and those described in the literature as safe amines Amines used.

Oxygen are suitable as oxidizing agents for the process according to the invention or an oxygen-containing gas, especially air.

The process according to the invention is carried out at temperatures in the range from 0 to 200 ° C, preferably 0 to 100 ° C, particularly preferably in the range of 50 to 70 ° C carried out.

The process according to the invention is carried out at pressures in the range from 0.01 × 10 ⁵ to 100 × 10 ⁵ Pa, preferably 3 × 10 ⁵ to 15 × 10 ⁵ Pa, particularly preferably 5 × 10 ⁵ to 12 × 10 ⁵ Pa. An increased oxygen partial pressure has an accelerating effect on the reaction rate. An oxygen partial pressure in the range from 3 × 10 ⁵ to 15 × 10 ⁵ Pa has proven to be advantageous, the range from 5 × 10 ⁵ to 12 × 10 ⁵ Pa is preferred.

As metal complexes soluble in the reaction medium in the sense of the invention Processes are suitable metal soluble in the present water / amine mixtures complex. Metals from groups 3 to 7 and  11 to 12 of the periodic table of the elements, particularly preferably copper, cadmium, Mercury, lanthanum, cerium, titanium, zirconium, vanadium, chromium, molybdenum and Manganese. All multidentate ligands, their Metal complexes are soluble in the reaction medium. Ethylene diamine is preferred tetraacetate, nitrilotriacetate, acetylacetonate, phthalocyanines, if necessary carboxylated or sulfonated porphyrins or optionally carboxylated or sulfonated hematin. Phthalocyanines are particularly preferred.

The metal complexes soluble in the reaction medium are in quantities in the range from 0.1 to 10 mmol of metal complex per mole of amine, preferably 0.1 to 0.7 mmol metal complex used per mole of amine. The optimal amount is natural depends on the molecular weight of the ligand used and can easily by few preliminary tests can be determined.

The metal complex soluble in the reaction medium can preferably be in its finished form be given, but also in a further preferred embodiment in situ are prepared from the corresponding metal salt and the ligand and as Solution are added to the reaction medium. Of course you can too Mixtures of various metal complexes soluble in the reaction medium be set.

Oxidation with oxygen or oxygen-containing gas is preferred for a pH in the range from 8 to 12, preferably from 8.5 to 10 carried out.

The reaction time depends strongly on the process conditions and is in the Range from a few minutes to several hours and can be easily adjusted by prior search can be determined.

The method according to the invention is carried out, for example, by that the oxygen or the oxygen-containing gas under the specified pressure, Temperature and other process conditions on the reaction medium presses, or pressed through the reaction medium, or is passed. The pro  product either precipitates from the reaction medium and is filtered off, or is caused by cooling or partial distillation of water to precipitate and filtered off or by distillative or extractive workup of the Separated reaction medium.

The process can be carried out batchwise or in a continuous procedure become. The metal complex soluble in the reaction medium can advantageously can be recycled and reused, possibly there is a cleaning stage here separation of by-products necessary.

The process according to the invention has yields of <90%. The products fall into high purity with less than 10 ppm catalyst metal content and are suitable for this reason it is an excellent vulcanization accelerator for sulfur crosslinking bare rubbers and / or as fungicides.

The following examples illustrate the invention.  

Examples Comparative example

100 g of 4-methylpiperazine and 40.2 g of NaOH in 500 ml of water were placed in a 2 l three-necked flask and reacted with 80 g of carbon disulfide at 10 ° C. overnight. The solution was then made from 50.5 mg of tetrasulfate sodium phthalocyanine and 12.5 mg of Co (Ac) ₂ . 4H ₂ O dissolved in 60 ml of water added. It was then heated to 60 ° C. and oxygen and carbon dioxide introduced for 15 hours. 40.3 g of yellow product precipitated out, which was identified as betaine due to its melting point of approx. 190 to 195 ° C and the IR spectrum. There was no evidence of the formation of a thiuram disulfide.

example 1

100 g of 4-methylpiperazine in 500 ml of water were placed in a 2 l three-necked flask submitted and at 10 to 20 ° C with 76 g of carbon disulfide in the course of 3 Hours spent on betaine. Then the dark solution became 60 mg of manganese chloride and 436 mg of tetrasulfonated, empty phthalocyanine (the Manganese phthalocyanine complex forms spontaneously with the formation of a dark one Solution). The solution is brought to pH 9 with 3 pills of sodium hydroxide and then charged with pure oxygen with good stirring. At a A temperature of around 60 ° C quickly sets in the oxidation. After about 14 hours stops the uptake of oxygen. It was suctioned off, well with water washed and dried in vacuo. 160 g of very light bis- (4-methyl piperazino) thiuram disulfide with a melting point of 148 ° C (91% of theory). In the product 8 ppm of manganese were contained.

The mother liquor with the dissolved manganese complex can be used for further oxidations. In this case z. B. found on the product 4 ppm manganese at 164 g (~ 93% yield) bis (4-methylpiperazino) thiuram disulfide at a melting point of 148 to 149 ° C.
C ₁₂ H ₂₂ N ₄ S ₄ , M = 350.5
Calculated:
C 41.1; H 6.27; N 15.96%;
found:
C 40.9; H 6.2; N 15.9%.

Claims (4)

1. A process for the preparation of a thiuram disulfide substituted with aliphatic, cycloaliphatic, araliphatic and / or aromatic hydrocarbon radicals by reacting one or more correspondingly substituted secondary amines with carbon disulfide in water and in the presence of oxygen or oxygen-containing gases and a metal-containing catalyst, characterized that one uses a metal complex soluble in the reaction medium as a catalyst, the metal being selected from groups 3 to 7, 11 and 12 of the periodic table of the elements. 2. The method according to claim 1, characterized in that one is soluble Metal complex a copper, zinc, cadmium, mercury, lanthanum, cerium, Titanium, zirconium, vanadium, chrome, molybdenum or manganese complex or mixtures of these are used. 3. The method according to claim 1, characterized in that one is soluble Metal complex uses a metal phthalocyanine complex. 4. The method according to claim 1, characterized in that one or more soluble metal complexes in amounts in the range of 0.1 to 10 mmol, be pulled to one mole of secondary amine.