HU194286B - Process for producing copolymeres from vinyl-pyrrolidones and maleinanhydrides - Google Patents

Abstract

Copolymeric poly-anions of formula (I) are prepd. by radical copolymerisation of a 1:1 mixt. of the monomers in an oxygen free organic solvent in the presence of a radical producing initiator, at 60-70 deg.C for 3-5 hrs. The prod. is purified pref. by extn. with benzene or chloroform, and opt. transformed into acid, amide or ehter. The concn. of comonomers is 2-3 mole per litre. - In the formula X+ = H, alkali-metal or an organic cation, R = -OH, -OR', -SR' or -NR'R'', R' = alkyl, alkenyl or alkinyl, aryl or a heterocyclic qp., R'' = H or R'.

Description

The present invention relates to a process for the preparation of maleic acids or copolymers of vinylpyrrolidone (I) in a quality that can be used for cosmetic purposes.

In the formula

X * is a proton or an alkali metal ion;

R is -OH or -NH-R ';

R 'is C2-C6 alkyl; n is an integer from 50 to 200.

A copolymer of vinylpyrrolidone and maleic anhydride is disclosed in U.S. Patent No. 2,667,949. U.S. Pat. The starting material used in the preparation of the product described herein. were reacted in a 1: 1 molar ratio at 60 ° C for 48 hours. The resulting product is a brown and powdery additive that improves soil structure and is not suitable for cosmetic use.

As an intermediate, a vinylpyrrolidone-maleic anhydride copolymer of formula (I) was prepared from monomers of formula (II) and (III) in a 1: 1 molar ratio according to U.S. Pat. in the Romanian patent. Thus, the starting total monomer concentration was 4 mole m ³ , the solvent used was dioxane and hexane, the reaction temperature was 80 ° C and the reaction time was 7 hours. These compounds, which have not been identified, have been shown to contain up to 15-20 molecules and the resulting low molecular weight copolymer is highly colored and can no longer be purified. This is because, on the one hand, the dioxan chain transfer effect of the solvent prevents the production of high molecular weight compounds and, on the other hand, the high concentration of total monomer at the required temperature prevents the formation of a pure product.

It is an object of the present invention to provide a colorless copolymer based on vinylpyrrolidone and maleic anhydride which satisfies the delicate requirements of the additives used in cosmetic products, i.e., it does not contain highly colored, contaminating (carcinogenic) material resulting from side reactions. consumes less energy and is always reproducible with the same results, providing a sufficiently high degree of polymerization.

In the process of the invention, the copolymer of formula (I) is co-polymerized with the monomers of formula (II) (1-vinyl-2-pyrrolidone) and the maleic anhydride of formula (111) and the poly (1 -Vinyl-2-pyrrolidone-co-maleic anhydride) is prepared by reacting the compounds of formula II and III in a 1: 1 molar ratio and a concentration of 1-3 mol.dm ³ (total monomer) in an organic solvent of 0.01-0 In the presence of 1 mol.dm- ^{3 of a} radical-producing initiator at 60-80 ° C for 3-5 hours in an oxygen-free medium, and the resulting crude product is purified by solvent extraction or precipitation. The product obtained is a copolymer of formula (IV) which is converted to a copolymer of formula (1) by hydrolysis with water or a basic aqueous solution or treatment with a C 2 -C 6 alkylamine in an alcoholic medium. The copolymer of formula (I) may be used as a starting material or additive in an amount of from 1 to 10% by weight, after appropriate cleaning. During acopolymerization, the monomers of formula (II) and (III) are incorporated into the polymer chain in a 1: 1 molar ratio, alternately, so that the product has a uniform chemical composition and structure. The incorporated compound of formula (II) provides water solubility of the copolymer and the compound of formula (III) provides reactivity. Due to the latter, the copolymer of formula (IV) can be converted into amides or esters by reaction with compounds having the appropriate functional groups, capable of chemically coupling sunscreens and thus modifying the activity properties of these compounds.

According to the invention, the copolymer of formula (IV) can be converted into an acidic derivative (formula (I) in which X ⁺ is a proton) and, as such, is advantageously used for the preparation of various cosmetic formulations. The pH of the aqueous solution of the copolymer may be adjusted from 2.0 to 8.5 as desired, preferably by adding a base (4.2 to 5.6) to the natural acidic protective layer of the skin. In this way, a cosmetic material is obtained which is compatible with both hydrophilic and lipophilic components, i.e., in both types of emulsions. Due to its high buffer capacity, this copolymer, when used in a few percent, ensures the acidic character of the composition. The copolymer is non-toxic to the living organism in the form of free acid (see formula V) and its sodium salt (formula VI). 2-pyrrolidone-5-carboxylic acid) or a macromolecular analogue thereof The copolymer combines known good properties of copolymers of polyvinylpyrrolidone and maleic anhydride with other monomers.

The invention is illustrated in detail by the following non-limiting Examples.

1-8. Examples 9 to 11 illustrate the preparation of the polymer of formula IV; Examples 1 to 5 relate to the chemical modification process of the polymer of formula (IV).

Example 1

In a 500 cm ³ volumetric flask, 24.5 g (0.25 mol) of maleic anhydride (m.p. 52-53 ° C) was dissolved in 420 cm ^{3 of} anhydrous benzene, freshly distilled (100 Pa) (26.7 cm ³⁾ (0.25 mol). 46 v) 1-Vinyl-2-pyrrolidone and 0.82 g (5 mmol) of AIBN (azo-di (isobutyronitrile)) initiator in 36 cm ^{3 of} dry benzene were added and made up to the mark with benzene. In the reaction mixture thus prepared, the total concentration of monomers used is 1.0 mol / dm ³ and the initiator concentration is 0.01 mol / dm ^-3 . The reaction mixture was charged to a flask with condenser, stirrer, gas inlet, and stirred at 60 ° C for 5 hours under a stream of nitrogen. The precipitated slightly yellowish precipitate was warm filtered and washed with benzene. Yield: 22 g, 42 weight. The product was purified by benzene extraction in a Soxhlet extractor on a G-3 glass filter for 24 hours. A colorless powder was obtained which had the following characteristics:

Inert solvents for the copolymer: dimethylformamide (DMF), cyclohexanone, dimethylsulfoxide.

Slowly soluble in water as anhydride groups convert to acid groups.

The copolymer is insoluble in: diethyl ether, hydrocarbons. Infrared spectrum (taken in KBr tablet):

Strong bands: 1850 and 1780 cm '(anhidridgyűrű characteristic vibration) and 1670 ^cm-1 (five-membered lactam ring).

Elemental analysis (C ₆ H ₉ NO + C ₄ H ₂ O ₃ ) _n = (209.2) calculated for C, Η, N based on molecular weight:

Calculated: C, 57.41; H, 5.30%; N, 6.70. Found: C, 57.21; % H, 5.50; N, 6.63.

Molecular weight determination:

The average molecular weight of the product calculated from the following equation is M - 18,500, which was determined by viscosity measurement at 25 ° C in an aqueous solution of pH 2.1. From the resulting intrinsic viscosity (η), the average molecular weight of the copolymer was calculated as follows:

[η] = 3.25 10 → M ° * ^J (Csákvári, Azori, Lung: Polymer Bulletin 1981 5 413-416.0).

The product contains 50:50% by weight of a major fraction having a molecular weight of 10,000 and 30,800. The latter contains fractions with molecular weights of 25,000,30,000 and 35,000. Ratio of maximum and minimum molecular weights:

^{Mjna ;:} _{= 3> 5} ^ min

Studies in white mice have shown that the aqueous solution of the product: polyvinylpyrrolidone-co-maleic acid [copolymer (V)] or its sodium salt (copolymer (VI)) is injected intraperitoneally at 800 mg / kg i.v. did not cause mortality at a dose of mg / kg.

2-5. example

In each case, the procedure of Example 1 was followed, but the total monomer concentration was changed to 2 mole mole, in the molar ratio of 1: 1, and the initiator concentration was changed as shown in Table 1. The results are shown in Table 1.

Table 1

Example total monomer concentration mole. dm ' ³ Initiator at the Concert Tram. dm ' ³ tem- ture C Time hour Evade- pro- duction t% Second 2 0,005 60 3 15 Third 2 0.02 60 3 46 4th 2 0.05 60 3 71 5th 2 0:10 6Q J „. 3 84

Example 6

All were carried out as in Example 1, but each reaction parameter was selected as follows: Total monomer concentration: 3 moles. dm ' ³ . Initiator concentration: 0.05 mol.dm ³ , reaction temperature: 70 ° C, reaction time: 3 hours. Yield: 80%. Purification: benzene extraction. The purified product had an average molecular weight of 19,000.

Example 7

In analogy to Example 1, we were ei as solvent toluene, dibenzoyl peroxide initiator was used 0.02 mól.dm ^'3 and a concentration of 2.0 mól.dm' using ^three összmonomer concentration, 80 ° C for 3 hours the copolymerization yielded a mass of 73%. The precipitate from toluene is colorless and well filtered. The purified product has a molecular weight of 14.600.

Example 8

All were carried out as in Example 1, but the reaction parameters were selected as follows: total monomer concentration. 3 mol.dm '³; initiator concentration: 0.02 mol.dm- ³ ; reaction temperature: 70 ° C; reaction time duration; 3 hours.

Yield: 78.5 mass. After chloroform extraction, the product has an average molecular weight of 21,000 and a very narrow distribution. The 6 fractions obtained by successive fractionation have the same molecular weights between 20,000 and 21,800.

The chemical modification of the copolymer of formula (IV) is illustrated below with some examples, without limiting the scope of the invention.

Example 9

The copolymer (IV) was dissolved in water and refluxed for 2 hours to ensure complete conversion. The solution was evaporated to dryness, dissolved in an equal volume of water, diluted with 2X ethyl alcohol and 4 times the volume of tetrahydrofuran. THF) and precipitated and filtered. The precipitate was water-31

In 194,286 it was redissolved and lyophilized under vacuum to remove the adsorbed precipitant (THF).

The product: Poly (1-vinyl-2-pyrrolidone-co-maleic acid) 5 (Formula V) is a colorless, odorless, photosensitive, air-insensitive, stable compound. Soluble in water, insoluble in tetrahydrofuran, ether. Its aqueous solution is acidic. Can be used in all acidic skin care and skin protection products. It has the advantage over low molecular weight acids (eg citric acid, boric acid, tartaric acid) used in cosmetics that it is compatible with both hydrophilic and lipophilic components. As a result, it also has an emulsion stabilizing effect.

Example 10

The copolymer of formula (IV) was hydrolyzed with 10% aqueous solution of sodium carbonate or sodium bicarbonate at room temperature. The product obtained is poly [1-vinyl-2-pyrrolidone-co-sodium maleate] (Formula VI), which may be prepared by the addition of an equivalent amount of NaOH to an aqueous solution of the copolymer V We are added.

Any other alkali metal salt can be prepared in a similar manner. Organic bases of the copolymer of formula (IV) may also be prepared in a suitable solvent.

The basic properties and applications of the copolymer of formula (VI) are similar to those of Example 9 for the copolymer of formula (V). A significant difference is that the copolymer salt has a buffering property.

Starting from the copolymer of formula (V), the pH of the solution can be adjusted with NaOH from 2.0 to 8.5 as desired. Preferably: 4-5 for acidic skin care products, 5-6 for hair conditioners.

Example 11 To a copolymer of formula (IV) was added 300 cm ^{3 of} ethyl alcohol and 5 cm ³ (1.5 equivalents) of n-butylamine were added dropwise with stirring. As a result of the amination reaction, the copolymer gradually dissolved over 30 minutes. The solution was stirred for an additional 30 minutes and then evaporated to dryness on a rotary evaporator. To remove excess butylamine, the material was dissolved in a little alcohol and evaporated again. The butylamine in the salt bond was removed by ion exchange.

Yield: 13.3 g, 98%. The product obtained is: Poly (1-vinyl-2-pyrrolidone-co-monobutyl maleic acid amide VII), colorless, very soluble in alcohol, freely soluble in benzene, in a limited amount of warm water, and mixed with water, glycerol such as acetone, chloroform, toluene, and limited ethyl acetate.

Claims (1)

A process for preparing a copolymer of formula (I) wherein n is an integer between 50 and 200 '; X ⁺ is a proton or an alkali metal ion; R is -OH or -NH-R '; R 'is a C 2 -C 6 alkyl group - of the monomers II and III of the formula I: I in an organic, inert solvent, oxygen-free medium, preferably in a nitrogen atmosphere, in the presence of a radical-producing initiator; monomers of formula I are dissolved in a concentration of 1-3 mol.dm ^-3 as an organic solvent in benzene, toluene or chloroform, in the presence of a 0.01-0.1 - preferably 0.02-0.05 mol.dm * ³ radical-producing initiator - 6070 The resulting copolymer of formula (IV) wherein n is purified by extraction with the same organic solvent, preferably benzene or chloroform, with water or a basic aqueous solution of 2-6 alkyl amine and optionally the product obtained with water or a C 1-2 alcohol or ion exchange and finally, if necessary, lyophilized.