CS252848B2 - Method of n-ethyl phenyldithio zinc carbamate production - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to zinc nonylphenyldithiocarbamate, which is used as an accelerator in vulcanization.

Methods for the preparation of zinc ethylphenyldithicarraamate are known in which Netyyaniline, carbon disulfide and zinc oxide are used as starting materials.

U.S. Pat. No. 2258847 discloses a process for the preparation of a metal dithiocarbamate which is based on a reaction between an alkylsilane-carbon disulfide and an alkali metal salt of a weak acid, the reaction being carried out in a solvent in which the reactants and by-products are dissolved and the product itself is insoluble. According to the present invention, the use in the synthesis of zinc oxide requires the use of acetic acid together with the solvent in the reaction medium. Under these conditions, the zinc oxide in the reaction medium becomes a soluble compound. The product is obtained with a melting point of from 475 to 475.5 K in a yield of 95.8%.

A method for the preparation of the zinc salt of alkali metal dithicarraamic acid is known from Czechoslovak patent No. 107070, which is based on the direct condensation of N, N, O, N, S, and zinc powder. The condensation is carried out at boiling point in the presence of 0.1 to 10% ammonium or alkali metal hydroxide and 0.1 to 5% arylsufoonic acid salt or phenolate type emulator. The reaction is carried out in a sulfuric acid wash ( _1). Zinc N-ethylphthylldithiocarbamate having a melting point of 477 to 479.5 K is obtained in a yield of 98.5%. _1к л pλílínř TVD / .I.> Dt ·. · Native product is obtained, mp 476 to 478 K in 90% yield. When performing hn? the reaction on an industrial scale does not achieve such high yields and product purity,.

A characteristic feature of the known processes is the use of polar solvents which do not participate in the reaction. In US Patent No. 2258947, the panning of a solvent with acetic acid enhances the reaction of all of the starting years in a disposable, liquid mixture.

In the case of the Czechoslovak patent No. 107070, the polar solvent facilitates the starting materials in a non-homogeneous environment, since it allows the dissolution of the condensation water to the organic, liquid phase. Better contact of the water with the zinc particles causes the formation of clumps, which makes it difficult to perform the process effectively. The use of non-participating solvents causes dilution of the reaction mixture, which negatively affects the reaction rate. For this reason, the process is carried out at the boiling point of the reaction mixture, causing loss of volatiles. In addition, polar solvents, which are usually alcohols, will cause a reduction in the yield of the ricket. To obtain higher yields, hydroxides are added to the reaction mixture. In embodiments in dia ^/ ys.oe méěítku ms is required after the regeneration-Uzi ·. ^ '·· !! This leads to increased costs.

The present invention relates to a process for the preparation of zinc N-ethylphenyldithiocarbamate, the immediate refiner of N-ethylaniline with carbon disulfide, filtration, washing, and drying the product. Polish invention consists in that the reaction is effected in the Sun ^ ltylinilinu Jato reaction medium, whereby in such όoužíje máiístuí _t to obtain such a slurry after the reaction, in

Preferably, the dispersion medium M-otyl is 1 and its putytet is preferably 80 to 120%, calculated on the basis of the mechanical quantity. It is also possible to employ surface-active, lipofibre-rich additives in the reaction in an amount of 0.1 to 8% by weight. u · u · ixodu ^ it.

The synthesis is carried out in pTo.e-i.

This yields a high quality product in quantitative yield. Using high excess - Otylani X - 'nu po.seu. · Equal to ¹ ''· transport reaction and ptor.o re.h ··? proceeds faster c je.n in sitNu hléveii · ·. · г ··. - '· .. .., ·: ··:' ..kcu nor-iaN jt by-kt, which is well within the scope of the initiative.

As a result, it is simplified to operate the feeder, since the reactor requires neither cooling nor heating since the temperature in industrial reactors does not normally exceed 315 K. The synthesis of zinc N-ethylphenyldithiocaramate in N-cyaniline is also very advantageous. forms a non-homogeneous mixture at all stages of the process. At the beginning of the reaction, there are two phases in the reactor, i.e. the liquid phase, the organic phase consisting of N-ethylailine and carbon disulfide and the solid phase consisting of zinc oxide. The condensation reaction produces a second, liquid phase, which is condensation water and a second solid phase, which is zinc N-ethylphenyldithiocarbamate. Upon completion of the synthesis, there are practically three phases in the reactor: an organic, a liquid phase, a liquid aqueous phase, and a solid phase for the product.

Under these circumstances, N-cyanine forms a very good dispersing effect. Due to the not very large difference between the density of water and N-cyanine, the water formed during the condensation is immediately dispersed in the organic phase, which successfully prevents the formation of clusters of zinc oxides formed by water. The zinc oxide content, which is very fine, the high density and the viscosity, in comparison with polar solvents, more effectively reduce the sedimentation rate of the zinc oxide particles, which facilitates the reaction.

For these reasons, the synthesis of zinc N-ethylphenyldithikecabbate works efficiently, even when using slow-running stirrers. An increase in the degree of homogenisation of the reaction mixture can be achieved by the addition of surfactants. Furthermore, the process of N-ceylaniline production has the advantage that due to the low solubility in the mother liquor, product losses are eliminated. In the process according to the invention, the filtrate after separation from the reaction mixture is separated after the reaction, dewatered and used as a raw material for further production. In this way, the product, dissolved in the organic phase and returned to the reactor, usually increases the yield of the process.

The process according to the invention yields the product in the form of crystals suitable for filtration and washing. The technical zinc N-4-phenylphenyldithiocarbamate, after drying, is in the form of a loose, non-dusting powder.

The process according to the invention is illustrated by two production examples.

lad

By inserting 1

m. 1 .t ^ lo ^ xyV ·.

'· ·· í. meadows · c'i'í mixtures / slow "on him μι 2 m ethyl IzaHinu ainkh ce p ^{r p} s d. retkL · · ··. at

4 ·. N ducts up to 49 dm ³ increase the product suspension. : k to be filtered. <· to add v>'' iy: i · h.

: .n.í 9 8% ^ актск back ^of sLex cJHadičem and pulse ^ m ^ em ,, concentration 99.5, 44 kg emuugátoru which is a mixture of Al-oxide zinnčnatéti lfe160 kg, the stirrer is put into operation and after a ¹ ro ^u ^^^ ⁱ ^ u ^{to the} bat on a ^{b h} freak MIC ^{hours 20} Bodin. ^T eplota na. about 315 K, keeping it at this value and finally spinning slowly. The product is further washed with water with the addition of a phase emulator and used.

882 kg of process yield t are removed by shaving and settling and the organol of fresh IN-ethyl aniline obtained at the next production batch. dit of hiocc-arbamate of zinc having a melting point of 478 K.

· I ni v, k.1. as in Example 1, with the difference that 3 to vb. ·.

The reactor is charged with batches of α-c, 1-aniline and 500 dm ^{3 of the} organic phase obtained from the filtrate according to the example according to the example of zinc di-lithilic crucate having a melting point of at least 478. ·. Yield · p> ^r ID sttžeeno it amounts to 99.3% zinc.

Claims (2)

SUBJECT OF THE INVENTION A process for the preparation of zinc N-ethylphenyldithiocarbamate by direct reaction of N-ethylaniline with carbon disulphide and zinc oxide, by filtration, by washing and drying the product, characterized in that the reaction is carried out in N-ethylaniline used in an amount such that wherein the liquid dispersing medium is N-ethylaniline and wherein its suitable excess is in the range of 80 to 120% based on the stoichiometric amount. 2. The process of claim 1 wherein the surfactant is a lipophilic surfactant in an amount of 0.1 to 8 percent by weight of the product.