SU988833A1 - Process for preparing polyphenols - Google Patents

Description

(54) METHOD OF OBTAINING FULL-FREE PHENOLS

The invention relates to the technology of polyphenol production and can be used in chemical industry, and the resulting polymers as the starting components for the synthesis of heat and heat resistant epoxy resins or as hardened. teli.

A known method for producing polyphenols by oxidative polycondensation of phenols (for example, phenol, cresol, hydroquinone) in the presence of aluminum, iron, and C13 halides.

However, this method is inherent in DI: a change in high amounts (equimole or in excess, equimole amounts in relation to the monomer) of expensive catalysts and oxidizing agents. The high corrosiveness of these components, the need for special equipment for the process, and the time-consuming deactivation and separation of the catalyst and oxidant, associated with the consumption of additional funds and energy, irreversible loss of catalysts and oxidizers after synthesis as waste and, finally, the utilization of the latter is essential reduces the practical significance of this tool.

The closest to the invention to the technical essence is the method of producing polyphenols, which consists in the oxidative polycondensation of phenols (in particular, hydroquinone) in the presence of hydrogen peroxide (perhydrol) at 30-90 ° C in aqueous

10 environment 2. ..

The disadvantages of this method are the use of a large amount of an expensive oxidant / i. . perhydrol (up to 2.3 mol per 1 mol of monomer); thanks to high cor-. Special activity equipment from corrosion-resistant materials is required for the synthesis and purification of target products - poly20 phenols. In addition, due to the pervasive explosiveness of perhydrol, complex process instrumentation and special precautions in production are required.

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The aim of the invention is to simplify the technology and ensure the safety of the process.

This goal is achieved. According to the method of producing polyphenols, oxidative polycondensation

phenols (for example, phenol, p-cresol, c1-L- alkyl (CdH-f-j) -phenol, J, and

(B-naphtholes) and hydroquinone are carried out in the presence of air oxygen in an aqueous-alkaline medium at 75155 ° C using 12-100 mol.% | 1 based on the starting phenol) alkali

Example 1. Synthesis of polyphenol

In a three-necked flask equipped with a mechanical stirrer, reflux condenser, and thermostat, 9.4 g (0.1 mol) of phenol, 10 g of a 56% KOH solution (0.1 mol) are placed and heated to 155 ° C for 6 h, blowing air through the reaction mixture (volumetric air velocity of 44.8 l / h). The reaction mixture is then neutralized with 20% hydrochloric acid and washed from the resulting KCf and unreacted phenol with warm water in a glass filter, then dried in a vacuum oven at 80 ° C to constant weight. The residue of phenol and KCJ are separated by conventional methods and used again. The polymer yield 45% by weight of phenol.

Example 2. In contrast to example 1, the amount of alkali is 0.05 mol. The procedure for the synthesis and isolation of polyphenol is similar to example 1.

Polyphenol yield 38% by weight of phenol.

Example Z. In contrast to example 1, the temperature is maintained at 125 ° C. The procedure for the synthesis and isolation of the polymer is similar to example 1.

Polyphenol yield 33% by weight of phenol.

Example 4. Synthesis of poly-p-cresol.

Polycondensation of cresol is carried out under conditions similar to the synthesis of polyphenol in Example 1. The isolation of the target product and unreacted p-cresol is carried out as follows. Upon completion of the reaction, the reaction mixture is neutralized with 20% hydrochloric acid and due to the formation of the organic phase (polycresol in cresol), the latter is removed on a separating funnel. It is then washed several times with water, azeotro and unreacted fi-cresol are removed under reduced pressure, which can be passed to the next batch without purification. The output of poly-P-cresol 40%.

PRI me R 5. Synthesis of poly- (alkyl) -Co H - -phenol.

The synthesis and isolation of polyalkylphenol is carried out under the same conditions of example 4. The polymer yield is 70%.

Example 6. Synthesis of poly-d-naphthol.

25 g of a 5.6% KOH solution (0.025 mol) were added to 7.2 g (0.1 mol) of dL-naphthol. The temperature is maintained up to. The separation of the polymer from water, KCl and traces of monomer after the reaction is carried out by filtration. Yield 98% with a reaction time of 10 hours.

Example 7. Unlike Example 6, the amount of alkali is 0.012 mol. The procedure of synthesis and isolation of poly-oi-naphthol is similar to Example 6.

Output 70% by weight of ot-naphthol.

Example 8. Synthesis of poly- / i naphthol.

Poly-ft-naphthol is obtained under similar conditions for the synthesis of poly-C-naphthol in Example 6. A polymer yield of 65%.

Example 9. Synthesis of polyhydroquinone.

The procedure, conditions for the synthesis and isolation of polyhydroquinone on the basis of hydroquinone are similar to example 6. Yield 80% with a reaction time of 5 hours.

Example 10. In contrast to example 9, the temperature is maintained at 75 ° C. The polymer yield 53%.

Synthesized polyphenols are dark brown or black powdered or viscous (polyalkyl- (, CdH-1-7 / -phenol), fusible (Tras 20-295 ° C) and soluble products. They form durable coatings from solutions and melts. , adheres strongly to metals and glass. Polyphenols exhibit properties characteristic of organic semiconductors.

By varying the conditions of synthesis, especially the temperature and the content of KOH, it is possible to change the properties of polyphenols in a wide range and in the desired direction.

Polyphenols have the ability to cure epoxy resins, forming a high-strength, heat and heat-resistant compositions. In this regard, they can be successfully applied as heat-resistant conductive (or antistatic) adhesives and varnishes.

The invention has the following advantages over the known. Owing to the replacement of perhydrol with air as an oxidizing agent, the need to use expensive equipment from special anti-corrosion agents is eliminated. materials. Common hardware is used. Process safety is ensured.

Replacing expensive and scarce perhydrol with a safe, cheap natural oxidizer — air with unlimited resources contributes to a sharp decrease in the cost of the target products — polyphenols.

Claims (2)

.Thanks to the high purity waste of the new process NaCS (or KC2 can be used as a raw material in chemical industry for its direct purpose. And if polyphenols are used as a starting component for the synthesis of epoxy resins, the need to neutralize water-alkaline solutions of polyphenol disappears altogether. Formula of invention phenols in an aqueous medium in the presence of an oxide. 1 gels, characterized by the fact that, in order to simplify the technology and ensure the safety of the process, acid is used as an oxidizing agent. type of air and the process is carried out at 75-155 C in the presence of 12-100 mol.% (based on the initial alkaline phenol. Sources of information. taken into account during eco-examination 1. Patent ONA 3678006, class 2 (60-47 R , published in 1972. 2. USSR author's certificate If 440387, cl. C 08 G 61/10, 1974. (Prototype) -.