JPH02233706A - Production of water-soluble polymer - Google Patents

Abstract

PURPOSE:To readily obtain the subject polymer for paper converting agent, etc., by introducing of amino group with acidic solvolysis of poly-N-vinyl carboxylic acid amide using mixed solvent of alcohol having specific boiling point and water, and removing water and by-produced acid by heating. CONSTITUTION:Poly-N-vinyl carboxylic acid amide expressed by the formula (R is H or CH3) (e.g., poly-N-vinyl acetamide) is subjected to solvolysis to prepare water-soluble polymer introduced of amino group using mixed solvent of alcohol having >=100 deg.C boiling point at atmospheric pressure (e.g., n-amyl alcohol) and water as reacting solvent and in an acidic condition by adding concentrated hydrochloric acid, then water and by-produced acid are removed to separate polymer to afford the aimed water-soluble polymer.

Description

[Detailed Description of the Invention] [Industrial Icheon Field] The present invention relates to a method for using water-soluble polymers useful in paper processing agents, polymer flocculants, stone I+I1 recovery agents, protective colloids, etc. In particular, water-soluble polymers containing primary amino groups obtained by acid modification of polyN-vinylcarboxylic acid amide, acid ringing of complete or partial hydrolysates of polyN-vinylcarboxylic acid amide (hereinafter referred to as "acid ring of polyvinylamine") The present invention relates to a method for easily recovering polyvinylamine acid salts in solid form.

[Conventional technology]

Conventionally, the method for obtaining polyvinylamine is the Hofmann decomposition method of polyacrylamide (Journal of Polymer Science Polymer Chemistry-29).
1239 (1985)) and a method obtained by decomposing a polymer of a cyclic N-vinylimide compound with hydrazine (Journal of the American Chemical Society 911 (+947)). Also poly N
- As a method for obtaining polyvinylamine acid salts by modifying vinylcarboxylic acid amide, a method has been reported in which a polymer of N-vinylacetamide is hydrolyzed in @acid aqueous solution (Journal of American Chemical Society 98 5996 (1976)). Furthermore, as a method for recovering the acid salt of polyvinylamine as a solid substance, JP-A-61-74700 describes a method for recovering a polymer when N-vinylacetamide and N-vinylformamide are used as N-vinylcarboxylic acid amide. A method for obtaining a solid polymer using methanol after hydrolysis in an aqueous hydrochloric acid solution is described. Japanese Unexamined Patent Publication 1986-1986
No. 0508 describes a method in which basic hydrolysis is performed in the presence of an alcohol having 1 to 4 carbon atoms and water, and the resulting product is recovered by adding f&acid. Japanese Patent Publication No. 63-66205, 976
02 contains 2 hydrolysates of polyN-vinylformamide.
After treatment with a divalent organic acid, the hydrolyzate was treated with an organic fI1
A method for recovering solid polymer is described as @.

[Problem to be solved by the invention]

According to conventional techniques, polyvinylamine acid salts can be obtained in the form of an aqueous solution, or by reprecipitation with a water-soluble organic solvent such as alcohol or acetone, or by reprecipitation with the addition of a solution of an acid. Polyvinylamine acid salts can be obtained in solid form. When an aqueous solution of a polyvinylamine acid salt is highly concentrated, its fluidity decreases significantly, making it difficult to handle. Also, at low concentrations, transportation costs are too high. If a solid state is to be recovered by reprecipitation, a large amount of non-solvent is required, which increases the cost of recovering the solvent. The use of concentrated acid solutions has disadvantages from safety and reactor material considerations. The method of adding and recovering the second component requires complicated operations. The present invention solves these problems and provides an industrially advantageous method for recovering the 1:2 salt of polyvinylamine in solid form.

[Means and actions for solving the problem]

In producing the acid salt of polyvinylamine as described above, the present inventors have developed a method for easily recovering the solid acid salt of polyvinylamine through simple operations without using a large amount of organic solvent or concentrated acid solution. As a result of intensive studies, we have arrived at the present invention. That is, when the present inventors produced a water-soluble polymer by modifying poly-N-vinylcarboxylic acid amide under acidic conditions, we used a solvent with a boiling point of 10 at atmospheric pressure as a solvent for the reaction.
Polyvinylamine acid salts are produced by solvolysis using a mixed solvent of alcohol and water at 0°C or higher, and then heated to remove moisture and by-produced acid, or to separate two layers that do not contain polymer. It has been found that the polyvinylamine acid salt can be easily recovered in solid form by separating and adding a water-soluble organic solvent to the remaining one deaf to make the polymer solid, followed by filtration and drying.

The present invention is characterized in that polyN-vinylcarboxylic acid amide is easily acidic hydrolyzed in an aqueous solution, that the acid salt of polyvinylamine as a product is insoluble in alcohol, and that it can be hydrolyzed in a mixed solvent of alcohol and water. This invention utilizes the fact that the solution after the reaction separates into two layers.

The present invention will be explained in detail below. The poly N-vinylcarboxylic acid amide used in the present invention is poly N-vinyl formamide or poly N-vinylacetamide, preferably poly N-vinylacetamide. Poly N-vinylcarboxylic acid amide may be produced by any method, such as solution polymerization, reverse-phase emulsion polymerization, reverse-phase suspension polymerization, precipitation polymerization, or bulk polymerization of the corresponding N-vinylcarboxylic acid amide. It can be manufactured by Alcohols used for solvolysis in coexistence with water include n-butanol, i-butanol, 2-butanol,
n-amyl alcohol, 3-methyl-1-butanol,
Monohydric alcohols such as hexanol, pentanol, octanol, 2-ethylhexanol, heptyl alcohol, methylisobutylcarbinol, nonyl alcohol, decyl alcohol, tridecyl alcohol, diethylene glycol. Triethylene glycol, 1.3
-butylene glycol, 1,4-butylene glycol,
Dihydric alcohols such as 1,5-pentadiol, 1,6 hexanediol, hexylene glycol, butyl cellosolve, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethyl diglycol, ethyl triglycol, 3-methoxybutanol,
Examples include alkoxyalkyl alcohols such as polyethylene glycol and polypropylene glycol. This alcohol may be insoluble or nf-soluble in water. If a substance with a carbon number of 3 or less or a boiling point under atmospheric pressure of less than 100° C. is used, water and by-product acid cannot be removed by heating, and furthermore, the reaction progresses slowly in terms of hydrolysis rate.

Preferred water κ for solvolysis in alcohol-water systems
is 3 to 50 times, preferably 5 to 30 times, and more preferably 10 to 20 times, based on the amide group of the poly-N-vinylcarboxylic acid amide. If the amount of water is too small, the reaction progresses slowly and is not practical. Moreover, even if a large amount is removed, there is no change in the reaction rate, and a large amount of energy is required for removal. There is no particular limitation on the ratio of alcohol and water, but in contrast to the conventional method using an aqueous solution, a large amount of water was required to ensure sufficient rIF performance for stirring. According to the above, wood r^ has the characteristic that a small amount is required compared to this. For this reason, in the present invention, the produced polymer can be easily taken out. As for the method of adding water, if the raw material polymer contains water, it may be added as is to the alcohol, or it may be added directly to the reactor, or it may be added together with the acid used. When saponifying using U acid, it is convenient to use concentrated hydrochloric acid (36z solution) and use the water contained in the concentrated hydrochloric acid. In addition, the polymer concentration is such that the amount of water is 5 to 5 relative to the amide group in the polymer.
0 times the mole, and the weight of the polymer relative to the whole is 0
．． 01 to 50 heavy scenes, preferably 1 to 30 heavy spots.

The acids used in this reaction are usually mineral acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and perchloric acid, formic acid, and trifluorochloric acid.
acid, organic acids such as sulfamic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and particularly preferably hydrochloric acid.

The amount of acid used is 0.00 with respect to the amide group of poly-N-vinylcarboxylic acid. It is 5 to 10 times the mole, preferably 1 to 5 times the mole. If it is too small, the reaction progresses slowly;
Also, many unreacted amide groups remain.

If there is too much, there are safety and economic problems.

The reaction temperature is 60-200°C, preferably 80-150°C. Use a pressure-resistant reactor if necessary. The lower the reaction temperature, the longer the reaction time. If it gets too high, it will lead to polymer deterioration.

It is known that alcohol is used as a reaction liquid in the solvable decomposition of poly-N-vinylcarboxylic acid amide under acidic conditions as in the present invention. Since the decomposed polymer is not soluble in alcohols, it is unclear how to treat it after the reaction, and it has not been easily recognized how it should be carried out.

After the reaction is complete, if the molecular weight of the modified polymer is relatively low, it will be in a state where it separates into two layers, and it will not contain this polymer at all! When the layers are separated, only the layer containing the polymer remains. If a water-soluble organic solvent is added here, the polymer can be easily taken out as a solid. The amount of organic solvent required at this time is much smaller than when the solvent is added to the entire polymer solution, and the significance of the present invention is significant. Any organic solvent may be used as long as it is water-soluble, and specific examples include methanol, ethanol, n-propyl alcohol, and isopropyl alcohol. Particularly preferred is methanol.

Further, when the molecular weight of the modified polymer is relatively high, the polymer becomes a hydrogel. At this time, an easy method is to remove the water and acid present in the system as volatile components to remove the polymer as a solid.

〔Example〕

The present invention will be specifically illustrated below with examples.

Example 1 Reduced viscosity 1.2 dl/g (0.1 dl/g in water at 30°C
2.3 g of poly N-vinylacetamide (measured at a polymer concentration of ). 36g of n-amyl alcohol. fA hydrochloric acid (36% solution)12. ．． was charged into a reaction vessel with an inner volume of 100 ml.

At this time, the amount of water is 16 times equivalent to the amide group. The reaction was carried out at 100°C. After 10 hours, the reaction solution was separated into two layers. Thereafter, the polymer was precipitated by heating to 140° C. to remove moisture. This was filtered and vacuum dried to obtain 2.0 g of polymer. The degree of modification to amine groups determined by titration was 81 mol2.

Example 2 Prepared in a pressure container using the same preparation claw as in Example L and heated to 140°C.
The reaction was allowed to proceed for 2 hours. After completion, remove the supernatant of the reaction solution,
After adding 20 ml of isopropyl alcohol to the residue to powderize the polymer, it was filtered and air-dried under TC to obtain Polymer 2.
1g was obtained. The modification rate to amino groups determined by titration was 97 mol%.

Example 3 Poly N-vinylacetamide 4.1 with reduced viscosity 4.2 dl/g (.n-amyl alcohol 18.8 g.
19.2 g of D salt # was charged into a pressure container. At this time, the amount of water is 14 times equivalent to the amide group.

The reaction was carried out at 140°C. After 1 hour, a part of the reactor was opened to remove water, and the precipitated polymer was taken out and dried under vacuum to obtain 3.8 g of polymer. The modification rate to amino groups determined by titration was 99 mol%.

Example 4 Poly N-vinylacetamide with a reduced viscosity of 2.6 dl/g 2. 3g. 2-ethylhexyl alcohol 36
g. 10 g of D hydrochloric acid was charged into a reaction vessel having an internal capacity of 100 ml.

At this time, the amount of water is 13 times equivalent to the amide group. The reaction was carried out at 140°C. After 1 hour, the reaction solution was separated into 2N. Thereafter, the supernatant of the reaction solution was removed, and 20 g of methanol was added to the residue to powder the polymer, which was filtered and dried under vacuum to obtain 2.1 g of polymer. The modification rate to amino groups determined by titration was 93 mol%.

Example 5 Poly N-vinylacetamide with reduced viscosity 8.6 dl/g 4.1. , n-amyl alcohol 55g. a Hydrochloric acid 9
．． 6 g and 1.1 g of water were placed in a pressure container. At this time, the amount of water is 8 times equivalent to the amide group. 140℃
I reacted with After 1 hour, a part of the reactor was opened and water and a
After removing the acid, the precipitated polymer was taken out by filtration and vacuum dried to obtain 3.8 g of polymer. The modification rate to amino groups determined by titration was 96 mol%. Example 6 2.3 g of poly N-vinylformamide with a reduced viscosity of 1.8 dl/g. 36g of n-amyl alcohol. 115 salt a 12g. was charged into a reaction vessel with an inner volume of 100 ml. At this time, the moisture content is 13 times that of the amide group.
: g-amount.

The reaction was carried out at 100°C. After 5 o'clock, the reaction solution had separated into two layers. Thereafter, the mixture was heated to 140° C. to remove water and formic acid, and a polymer was precipitated. This was filtered and vacuum dried to obtain 1.9 g of polymer. The modification rate to amino groups determined by titration was 95 mol%.

Comparative Examples> Example 1 Poly N-vinylacetamide 2.3 K having a reduced viscosity of 2.1 dl/g was charged into a reactor together with 12 g of concentrated INK acid and 30 ml of water. At this time, the amount of water is 77 times greater than the amide group. The reaction was carried out at 140°C. 2pm rt
nf & reaction solution was a homogeneous solution.

Example 2 Poly N-vinylacetamide with water content of 77% and reduced viscosity of 2.3 dl/g 2.31. was added to 35 g of n-amyl alcohol, and then hydrogen chloride gas was blown into the solution. The amount of hydrogen chloride dissolved was 2.98 g by neutralization titration. At this time, the amount of water is 3.6 times equivalent to the amide group.
The reaction was carried out at 140°C for 2 hours. The modification rate to amino groups is 2
It was 8 mol%.

Comparative Example 3 A reaction was carried out using a pressure vessel under exactly the same conditions as in Example 1 except that amyl alcohol was replaced with isopropyl alcohol. At this time, the amount of water is 1 for the amide group.
It is 6 times the equivalent amount. The modification rate to amine groups was 38 mol%, and the reaction did not progress much.

〔effect〕

According to the present invention, paper processing agents, polymer flocculants, oil recovery agents, and protective The acid salt of polyvinylamine, which is a water-soluble polymer useful for colloids, can be easily extracted as a solid.

Claims (3)

[Claims] (1) [I] Poly N-vinyl cal represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [I] When producing a water-soluble polymer by modifying bony acid amide under acidic conditions, the solvent used in the reaction A water-soluble polymer with amino groups introduced is produced by acidic solvolysis using a mixed solvent of alcohol and water with a boiling point of 100°C or higher at atmospheric pressure, and then heated to remove moisture and by-produced acid. A method of manufacturing by removing water-soluble polymers. (2) [I] Poly N-vinyl carbon ▲ mathematical formula,
Chemical formulas, tables, etc. are available ▼ [I] When producing a water-soluble polymer by modifying rubonic acid amide under acidic conditions, a mixture of alcohol with a boiling point of 100°C or higher at atmospheric pressure and water is used as a solvent during the reaction. A water-soluble polymer into which amino groups have been introduced is produced by solvolysis using a solvent, and after the reaction is completed, the layer that does not contain the polymer is separated into two layers, and then a water-soluble organic solvent is added. A method for producing solid polymers by adding (3) The aqueous solution according to claims 1 and 2, wherein the amount of water in the solvent during the reaction is 5 to 50 times the mole of the amide group of the poly-N-vinylcarboxylic acid amide. A method of producing a polymer.