SU763335A1 - 2,4-diisothiccyanatostyrene as monomer for preparing reactive polymers and copolymers - Google Patents

Description

The invention relates to the synthesis of monomers to obtain reactive polymers, namely to the synthesis of 2,4-diisothiocyanatostyrene.

When polycondensed with diamines, 2,4-diisothiocyanatostirol forms practically useful polymers containing grafted vinyl group copolymerizations. The polymers and copolymers of 2,4-diisothiodiananostirol in the vinyl group can be used to obtain complex ¹⁰ forming selective ion exchangers, bactericidal preparations. prolonged action, structurally colored and stabilized polymeric materials, etc.

Known 4-isothiocyanatostyrene, which ^{, S is} also used to obtain reactive polymers, for example, containing thiosemicarbazide groups, etc. [1].

However, when it is received, only the n-nitroisomer is used, which increases the cost of the final product.

The purpose of the invention is the use of 2,4-diisothiocyanatostirol in the preparation of reactive polymers and copolymers that are readily chemically modified.

These properties are determined by the chemical structure of 2,4-diisothiocyanatostirol, which is expressed by the following formula

(1)

2,4-Diisothiocyanatostirol is obtained by treating 2,4-diaminostyrene formed during the reduction of 2,4-dinitrostyrene (without isolating the reduction product from the reaction medium) with thiophosgene at 30-40 ° C.

The reduction of 2,4-dinitrostyrene is carried out with zinc dust in an aqueous acetone medium in the presence of ammonium chloride. Zinc dust is added during cooling in large portions, creating a large excess of reducing agent in the initial recovery period. In this case, the temperature rises spontaneously. to 40-43 ° C, then raise it to 50-54 ° C and maintain for 1 h. Under such conditions, the recovery proceeds smoothly to the corresponding diaminostyrene. However, attempts to highlight

2,4-diaminostirol from an acetone solution ends with gum formation. ₅

In order to convert 2,4-diaminostirol to a more stable compound (-2,4-diisothiocyanatosyrrole-), the reaction mixture is treated directly with thiophosgene. The best yield of the target product is obtained when the acetone ιό solution, after filtration of excess zinc dust and zinc oxide, is diluted with water and extracted with petroleum ether or hexane. If the product is obtained with preliminary distillation of acetone, then the yield of 2,4-diisothiocyanatostyrene is reduced by 45%. The yield of the desired product is even less if the reduction is carried out in a concentrated solution using a small excess of zinc dust. In this case, the reaction is accompanied by side processes of condensation or polymerization of 2,4-diaminostirol and treatment of the reaction mixture with thiophosgene does not lead to the formation of 2,4-diisothiocyanatostirol; Negative results are also obtained when ₂ s reduction is carried out at 55-60 ° C. The use of a large excess of zinc dust, vigorous mixing, and observing the temperature regime can eliminate side processes.

Zinc dust, which is isolated after the reaction ₃₀ tion together with zinc oxide, but the secondary use.

Example. To a mixture of 2 g of 2,4-dinitrostyrene, 2 g of ammonium chloride, 30 ml of acetone and 20 ml of water are added in large portions of _3J with vigorous stirring and cooling 24 'g of zinc dust. Thus there is a spontaneous rise in temperature to 40-43 ° C. After addition of the total amount of the reducing agent temperature was raised to 50- ₄ θ 52 ° C and maintained for 1 hour. The precipitate was filtered off, washed on the filter with acetone and transferred to a three-necked flask.

To the filtrate containing 2,4-diaminostyrene is added, under vigorous stirring _4J and cooling, 1.8 ml of thiophosgene at such a rate that the temperature does not exceed 40 ° C. After adding thiophosgene after 15-20 minutes, the reaction mixture was diluted with water and the product was extracted with hexane. The organic layer was separated, dried with anhydrous sodium sulfate and the solvent was distilled off. The yield of crude product is 1.85 g (84%). Recrystallization from hexane gives 1.6 g (73%) of needle crystals.

Elemental analysis of matter, Xu HgNjSj

Found,%: C 54.82; H 2.98; N, 12.82; S 28.77.

Calculated,%: C 54.90; H 2.70; N, 12.80; S 29.30.

Thus, 2,4-diisothiocyanatostirol is obtained on the basis of a more affordable and cheaper compound than the known 4-isothiocyanatostyrol. The process is carried out without preliminary isolation of the intermediate 2,4-diaminostyrene, which reduces the cost and simplifies the synthesis of the target product. In addition, the monomer has one more isothiocyanate group than

4-isothiocyanatostyrene, as a result of which the same effect is obtained (structural staining, stabilization, ion exchange capacity, fixing the enzyme to the polymer, etc.)

2,4-diisothiocyanatostirol is consumed 2 times less than 4-isothiocyanatostirol; the capacity of poly-2,4-diisothiocyanatostyrene is 2 times greater than the capacity of poly-4-isothiocyanatostyrene.

Claims (2)

Claim 2,4-diisothiocyanatostyrene of the formula • H ₂ C = HC - ^^> - NC5 NC5 as a monomer to produce reactive polymers and copolymers.