RU2269531C1 - Method for preparing tetra-(4-tertiary-butyl)-phthalocyanine - Google Patents

Abstract

FIELD: organic chemistry, chemistry technology.

SUBSTANCE: invention relates to the improved method for preparing tetra-(4-tert.-butyl)-phthalocyanine. Method involves heating 4-tert.-butylphthalonitrile with compound of alkaline metal and the following demetallization of formed product. As compound of alkaline metal method involves dry sodium hydroxide and heating up is carried out to temperature 200-220°C and formed melt is kept at this temperature for 10-15 min. Method provides simultaneous significant simplifying and decreasing cost the method for preparing tetra-(4-tert.-butyl)-phthalocyanine and to enhance the yield of the end product by 1.75-fold.

EFFECT: improved preparing method.

2 cl, 1 tbl, 1 ex

Description

Introduction

The invention relates to the chemical industry, and in particular to methods for producing tetrapyrrole macroheterocycles - tetraarenoporphyrazines, i.e. porphyrazines linearly annelated by aromatic or heteroaromatic rings containing various substituents, specifically to a method for producing tetra- (4-tert.-butyl) -phthalocyanine.

State of the art

Tetrapyrrole macroheterocyclic compounds play an important role in wildlife and technology, entering the structure of respiratory pigments, enzymes, vitamins, catalysts, sensors, semiconductors, etc.

The preparation of metal-free tetraarenoporphyrazine usually involves the template synthesis of its labile metal complexes with magnesium or its sodium, potassium or lithium salts from aromatic o-dinitrile, with their subsequent demetallization, and always presents certain difficulties. These include the instability of ligands under the conditions of demetallization of labile complexes and poor reproducibility, as well as low yields upon receipt of sodium, potassium, or lithium salts.

The only known method for producing tetra- (4-tert.-butyl) -phthalocyanine, (Mikhalenko S.A., Barkanova S.V., Lebedev O.L., Lukyanets E.A. ZhOKH, 1971, Vol. .12, C.2738), consisting in the fact that a mixture of 4-tert.-butylphthalonitrile and catalytic amounts of ammonium molybdate is boiled for 5 hours in a solution of sodium isoamylate in anhydrous isoamyl alcohol. The mixture was evaporated to 1/5 of the volume and demetallization of the resulting product was carried out by 7.5-fold dilution with methanol and stirring for several hours. The precipitate formed is filtered off, washed with methanol, and dried. For purification, the product is dissolved in chloroform and chromatographed on alumina.

The disadvantages of this method are the complexity, high cost of the reagents used and the low yield of the target product. The complexity is due to: multi-stage - 7 technological operations, taking into account the preparation of sodium isoamylate and the absolute isoamyl alcohol; the complexity of operations such as the preparation of sodium isoamylate, the absolutization of isoamyl alcohol, and the evaporation of the reaction mixture; the duration of the absolute alcohol and evaporation of the reaction mixture; using special precautions when working with anhydrous media and reagents (absolute isoamyl alcohol and metallic sodium). The yield of the target product is 56%.

SUMMARY OF THE INVENTION

The objective of the invention is to find a method for producing tetra- (4-tert-butyl) -phthalocyanine by heating 4-tert-butylphthalonitrile with an alkali metal compound and subsequent demetallization of the resulting product, which would be simplicity at the same time, using cheap reagents and higher yield of the target product .

The problem is solved by the method of producing tetra- (4-tert-butyl) -phthalocyanine by heating 4-tert-butylphthalonitrile with an alkali metal compound and subsequent demetallization of the resulting product, in which dry sodium hydroxide is used as an alkali metal compound, heating is carried out to a temperature 200 ÷ 220 ° C and withstand the formed melt at this temperature for 10 ÷ 15 minutes.

Distinctive features of the method are the use of dry sodium hydroxide as an alkali metal compound, heating to a temperature of 200 ÷ 220 ° C and maintaining the formed melt before demetallization at this temperature for 10 ÷ 15 minutes.

These features for the production of tetra- (4-tert.-butyl) -phthalocyanine are not known.

The invention allows to significantly simplify and reduce the cost of the method for producing tetra- (4-tert.-butyl) -phthalocyanine and increase the yield of the target product.

The simplification of the method is achieved by: reducing the number of technological operations from 7 to 6; elimination of such time-consuming and most lengthy operations, such as the absolutization of isoamyl alcohol and evaporation of the reaction mixture; elimination of anhydrous media and reagents (absolute isoamyl alcohol and metallic sodium), requiring the use of special precautions when working.

The cheaper method is achieved by replacing expensive reagents: isoamyl alcohol, sodium and methanol with cheap sodium hydroxide.

The yield of the target product rises to 98%.

In addition, the method can dramatically increase the reproducibility of the results.

Information confirming the possibility of carrying out the invention

For the implementation of the invention, the following substances are used: 4-tert-butylphthalonitrile obtained by the method (Mikhalenko S.A., Barkanova S.V., Lebedev O.L., Lukyanets E.A. ZhOKH, 1971, T.41, vol. .12, P.2738), and sodium hydroxide grade "hch" GOST 4328-77.

To obtain tetra- (4-tert-butyl) -phthalocyanine, 1 g (5.5 mmol) of 4-tert-butylphthalonitrile is mixed with 1 g of dry sodium hydroxide, heated to a temperature of 200 ÷ 220 ° C and the resulting melt is maintained at this temperature for 10 ÷ 15 minutes. Then the reaction mixture is cooled, washed with distilled water and the precipitate is filtered off. The resulting product is subjected to demetallization, for example, by successive washing on the filter with distilled water until the filtrate is neutral, then slowly 50 ml of 10–35% hydrochloric acid and again with water until the filtrate is neutral, or by reprecipitation from concentrated sulfuric, phosphoric or trifluoroacetic acids, or prolonged washing with methanol.

Received tetra- (4-tert.-butyl) -phthalocyanine in the form of a bright blue crystalline substance.

The target product can be purified by known methods, for example, chromatography on silica gel 0,040 ÷ 0,063 mm company "Merk".

The product was identified by the elemental composition and electronic absorption spectrum of the solution in benzene.

The yield of the target product during the implementation of the method using various temperatures and holding times is shown in the table.

Table
The yield of the target product Holding temperature, ° С Holding time, min Product yield,% 200 10 96 210 10 96 220 fifteen 96 220 fifteen 98

Claims (1)

A method of producing tetra- (4-tert-butyl) -phthalocyanine by heating 4-tert-butylphthalonitrile with an alkali metal compound and subsequent demetallization of the resulting product, characterized in that dry sodium hydroxide is used as the alkali metal compound, heating is carried out to a temperature of 200 ÷ 220 ° C and maintain the formed melt at this temperature for 10 ÷ 15 minutes