KR100531115B1 - Recovery of diallyldimethylammoniumchloride - Google Patents

Abstract

The present invention relates to a method for separating and recovering diallyldimethylammonium chloride, and more particularly, in the process of preparing diallyldimethylammonium chloride by reacting an aqueous dimethylamine solution with allyl chloride in the presence of an aqueous sodium hydroxide solution. Sodium chloride is washed with C ₁ to C ₃ lower alcohols to separate and recover the diallyldimethylammonium chloride remaining on the surface to improve yields, resulting in many industrial fields such as cosmetics, starch, detergents, papermaking, adhesives, textiles and water treatment. The present invention relates to a method for separating and recovering diallyldimethylammonium chloride from a byproduct of a diallyldimethylammonium chloride manufacturing process usefully used in the present invention.

Description

Separation and recovery method of diallyldimethylammonium chloride {Recovery of diallyldimethylammoniumchloride}

The present invention relates to a method for separating and recovering diallyldimethylammonium chloride, and more particularly, in the process of preparing diallyldimethylammonium chloride by reacting an aqueous dimethylamine solution with allyl chloride in the presence of an aqueous sodium hydroxide solution. Sodium chloride is washed with C ₁ to C ₃ lower alcohols to separate and recover the diallyldimethylammonium chloride remaining on the surface to improve yields, resulting in many industrial fields such as cosmetics, starch, detergents, papermaking, adhesives, textiles and water treatment. The present invention relates to a method for separating and recovering diallyldimethylammonium chloride from a byproduct of a diallyldimethylammonium chloride manufacturing process usefully used in the present invention.

Diallyldimethylammonium chloride (hereinafter referred to as 'DADMAC') is made of polymer by polymerization and is widely used as a key raw material throughout the industry such as cosmetics, starch, detergents, papermaking, adhesives, textiles and water treatment.

As a general method for producing DADMAC, a method of adding excess allyl chloride to a secondary amine (US Patent Nos. 3324740, 4151202, 4946996, Japanese Patent Application Publication No. 60-184052) and the like are known. have.

The DADMAC monomer is reacted in the presence of an aqueous sodium hydroxide solution to produce a DADMAC monomer as a by-product and sodium chloride as a by-product, as shown in the following Formula 1.

_{NaOH + 2CH 2 CHCH 2 Cl +} H (N) (CH 3) 2 → (CH 2 CHCH 2) 2 (N +) (CH 3) 2 (Cl -) + NaCl + H 2 O

At this time, sodium chloride, a by-product of the reaction, should be removed as much as less than 1% in order for DADMAC to be used as a raw material for cosmetics, starch, detergents, papermaking, adhesives, and fibers. The method of concentrating the aqueous solution of DADMAC monomer by vacuum drying is generally used. However, DADMAC monomer, which is a product, also remains on the surface of the sodium chloride precipitated as a solid during the separation and removal of sodium chloride by filtration, resulting in a decrease in the yield of the entire process. There is a problem.

Accordingly, the present inventors have conducted research to efficiently separate and recover DADMAC present on the surface of sodium chloride, a by-product generated during the manufacturing process of diallyldimethylammonium chloride (DADMAC), and thus, lower liquid alcohols such as methanol, ethanol, and propanol are used. Differences in the solubility of sodium chloride and DADMAC resulted in the separation and recovery of most DADMACs.

Accordingly, an object of the present invention is to provide a method for efficiently separating and recovering DADMAC by using a difference in solubility in liquid alcohols of C ₁ to C ₃ .

The present invention provides a process for preparing allyldimethylamine by reacting an aqueous dimethylamine solution with allyl chloride in the presence of an aqueous sodium hydroxide solution, and a method for producing diallyldimethylammonium chloride by reacting the allyldimethylamine with allyl chloride.

Separating the sodium chloride by vacuum concentration of the diallyldimethylammonium chloride prepared above at 40 to 60 ° C. and 35 to 45 torr;

The separated sodium chloride is separated by the alcohol containing sodium chloride and diallyldimethylammonium chloride by adding C ₁ to C ₃ lower alcohols in a weight ratio of 1 to 3 based on sodium chloride; And

Recovering the alcohol by drying the vacuum containing diallyldimethylammonium chloride at 20 to 40 ° C. and 15 to 25 torr;

There is a feature in the method for separation and recovery of diallyldimethylammonium chloride comprising a.

Hereinafter, the present invention will be described in more detail.

As shown in the above formula, the product produced by the reaction of the dimethylamine aqueous solution and allyl chloride in the presence of aqueous sodium hydroxide solution, in addition to the desired diallyldimethylammonium chloride, sodium chloride containing diallyldimethylammonium chloride and unreacted dimethyl Amines, allylchloride and allyldimethylamine are simultaneously left. Conventionally, the by-products can be separated, but diallyldimethylammonium chloride, which remains on the surface of sodium chloride, is almost impossible to separate and recover, thus affecting productivity such as yield.

The present invention washes the sodium chloride produced as a by-product during the separation and recovery of diallyldimethylammonium chloride with a lower liquid alcohol of C ₁ to C ₃ to utilize the difference in the solubility of sodium chloride and diallyldimethylammonium chloride in the alcohol. A method for significantly improving the yield of phosphorus diallyldimethylammonium chloride.

The specific alcohol used in the washing is a C ₁ ~ C ₃ lower alcohol having a boiling point of 40 ~ 90 ℃, high alcohol outside the above range of high boiling point is not easy to recover the alcohol as well as mixed with DADMAC There is a problem that it is difficult to recover by forming a gelled substance. In addition, organic solvents generally used for washing organic compounds, for example, organic solvents such as methylene chloride, tetrahydrofuran, acetone, etc., having a low boiling point, are not suitable because DADMAC is not dissolved and cannot be recovered.

Therefore, the present invention is characterized by the technical configuration of using a specific C ₁ ~ C ₃ lower alcohol that is not mixed with DADMAC and easy to recover while having a low boiling point, except for the other components attached to the surface Only the specific ingredient DADMAC is dissolved in high yield.

In the present invention, the alcohol is used in an amount of 1 to 3 parts by weight based on sodium chloride which is a by-product containing diallyldimethylammonium chloride, and when the amount is less than 1 part by weight, the remaining DADMAC monomers on the surface of sodium chloride are not easily washed, and thus effective recovery. There is a problem in that the use of excess in excess of 3 weight ratio, there is a problem that the recovery of alcohol is not efficient.

In the present invention, a reaction of dimethylamine and allyl chloride is formed in an aqueous sodium hydroxide solution. Sodium hydroxide is used as an aqueous solution, and sodium hydroxide is dissolved in a concentration of about 10 to 55% by weight, preferably about 35 to 45% by weight. It is good to maintain, and if the amount of dissolution is less than 10% by weight, there is a problem that it takes a long time to concentrate due to the use of excess water, and when it exceeds 55% by weight, there is a manufacturing problem according to solubility. In addition, in the case of dimethylamine used as a raw material of the reaction, the boiling point is lower than 10 ° C and is mostly used in an aqueous state because it is a highly toxic substance. The dimethylamine may be dissolved in 30 to 65% by weight, preferably 50 to 60% by weight, to maintain a constant concentration. When the dissolved amount is less than 30% by weight, the reaction volume becomes large and exceeds 65% by weight. In this case, it takes a long time to concentrate, and there is a problem that dimethylamine dissolved in an aqueous solution easily flows out when the solubility of dimethylamine is almost saturated and exposed to the air. In the case of allyl chloride, another raw material of the reaction, the higher the purity, the better the reaction formation.

As for the molar ratio of dimethylamine: sodium hydroxide: allyl chloride used by this invention, it is more preferable to form 1: 1: 1-2: 1: 1.2. If the molar ratio of sodium hydroxide is used in a small amount below the above range, the pH of the DADMAC becomes too low, causing problems in use, and in the case of using it in excess of the range, the generation of impurities causing the smell and color of the DADMAC monomer, etc. Problem occurs. Allylchloride also uses 50% in the formation of allyldimethylamine intermediate and the rest re-reacts with the purified intermediate to form DADMAC. If such allyl chloride is used below the above range, there is a problem that the yield of the reaction is lowered, and if it exceeds, there is a problem that it takes a long time to recover after completion of the reaction.

Meanwhile, the separation and recovery method of diallyldimethylammonium chloride (DADMAC) will be described in more detail as follows.

First, an aqueous solution of dimethylamine was added to the reactor under aqueous sodium hydroxide solution, and allyl chloride was supplied and reacted for 2 to 4 hours while maintaining the temperature inside the reactor at -20 to 25 ° C, more preferably at -10 to 10 ° C. An aqueous allyldimethylamine solution containing phosphorus by-product is obtained. If the reaction temperature is lower than -20 ℃, the reaction rate is lowered, if the reaction temperature exceeds 25 ℃, the side reaction problem occurs.

DADMAC is prepared by heating the reaction temperature of the aqueous allyldimethylamine solution containing the by-product obtained above to 30-60 ° C., and supplying allyl chloride.

Since DADMAC obtained above contains unreacted dimethylamine, allyl chloride, allyldimethylamine, etc., vacuum concentration is performed on 40-60 degreeC and 35-45 torr conditions in order to remove these. If the temperature during the concentration is less than 40 ℃ to increase the degree of vacuum, if it exceeds 60 ℃ there is a problem that by-products that cause the color is generated and at the same time salt size is reduced and difficult filtration.

By-product sodium chloride is concentrated to a solid phase by concentration, which is washed with a C ₁ to C ₃ liquid alcohol to separate and recover the DADMAC present on the sodium chloride surface. The alcohol is vacuum dried at 20 to 40 ° C. and 15 to 25 torr to recover the alcohol.

According to the present invention by washing the by-product sodium chloride with alcohol to separate and recover the remaining DADMAC on the surface has the effect of improving the overall yield of DADMAC.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention.

Example 1

Allyldimethylamine was prepared by reacting 1 mol of 60 wt% dimethylamine and 1 mol of allyl chloride in 1.01 mol of 40 wt% aqueous sodium hydroxide solution at −5 ° C., followed by stirring for 30 minutes, followed by heating to 50 ° C. 1 mol of allyl chloride was further added thereto to obtain 1 mol of an aqueous solution of DADMAC monomer at about 60% by weight. In order to remove the unreacted dimethylamine, allyl chloride, allyldimethylamine, etc. which remain in the obtained DADMAC monomer aqueous solution, it concentrated under the vacuum of 50 degreeC and 40 torr. The sodium chloride produced as a by-product after concentration was about 1 mole and solid. After separation of the aqueous DADMAC monomer solution and sodium chloride by filtration, methanol was added to the solid sodium chloride so that the weight ratio between methanol and solid sodium chloride was 1.0, followed by washing, and methanol containing sodium chloride and DADMAC monomer was separated by filtration. It was. In order to remove methanol in DADMAC monomer, vacuum drying was carried out at 30 ° C. and 20 torr. The yield recovered by methanol and the composition of the recovered DADMAC monomer in the amount of DADMAC monomer remaining on the sodium chloride surface are shown in Table 1 below.

Example 2

The same procedure as in Example 1 was carried out except that methanol was used in a 1.5 weight ratio to recover the DADMAC monomer remaining on the solid sodium chloride surface. The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 3

The same procedure as in Example 1 was carried out except that methanol was recovered in a 2 weight ratio to recover the DADMAC monomer remaining on the solid sodium chloride surface. The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 4

The same procedure as in Example 1 was carried out except that methanol was replaced in a 3 weight ratio to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 5

The same procedure as in Example 1 was carried out, but in place of 1.0 weight ratio of ethanol to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 6

In the same manner as in Example 1, but was carried out in place of 1.5 weight ratio of ethanol to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 7

In the same manner as in Example 1, but was carried out in place of 2 weight ratio of ethanol to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 8

In the same manner as in Example 1, but was carried out in place of 3 weight ratio of ethanol to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Example 9

The same procedure as in Example 1 was carried out, but in place of 2.0 parts by weight of propanol to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Comparative Example 1

In the same manner as in Example 1, but in place of a weight ratio of 2.0 to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Comparative Example 2

In the same manner as in Example 1, but was carried out in place of the methylene chloride (MC) 2.0 weight ratio to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

Comparative Example 3

The same procedure as in Example 1 was carried out, but in place of 2.0 parts by weight of tetrahydrofuran (THF) to recover the DADMAC monomer remaining on the solid sodium chloride surface.

The yield of the DADMAC monomer recovered from the sodium chloride surface and the composition of the recovered DADMAC monomer are shown in Table 1 below.

division Solvent (wt% ¹⁾ ) DADMAC recovery rate ²⁾ (%) Composition of recovered DADMAC (% by weight) DADMAC Sodium chloride Water and impurities Example 1 Methanol 1.0 64.2 69.1 0.22 30.7 Example 2 1.5 70.5 72.8 0.13 27.1 Example 3 2.0 56.1 76.3 0.18 23.5 Example 4 3.0 50.4 76.5 0.05 23.5 Example 5 ethanol 1.0 72.0 77.2 0.09 22.7 Example 6 1.5 80.0 72.4 0.23 27.4 Example 7 2.0 74.4 79.7 0.08 20.2 Example 8 3.0 63.2 71.2 0.19 28.6 Example 9 Propanol 1.5 58.3 69.3 0.01 30.7 Comparative Example 1 water 1.5 0 0 - - Comparative Example 2 MC 1.5 0 0 - - Comparative Example 3 THF 1.5 0 0 - - ¹⁾ Solvent (wt%) = (Alcohol weight / Sodium chloride weight) ㅧ 100 ²⁾ Recovery rate of DADMAC monomer (%) = Amount of DADMAC actually recovered / Amount of theoretical DADMAC ㅧ 100

As shown in Table 1, Examples 1 to 9 in which the DADMAC monomer remaining on the precipitated sodium chloride surface were washed with lower alcohols such as methanol, ethanol, and propanol were DADMAC which is a target product among the DADMAC monomers recovered from the sodium chloride. The monomer content was about 70-80% by weight and the recovery rate was up to 80% using ethanol solvent. However, in the case of using water as in Comparative Example 1, DADMAC as well as sodium chloride were dissolved together and recovery was not possible. It was not possible to recover.

As described above, the present invention enables the separation and recovery of DADMAC monomers from the precipitated sodium chloride as well as the DADMAC monomers produced by the reaction, and at the same time, the concentration of sodium chloride is significantly reduced to less than 0.23%. By doing so, it can be usefully used in various industries such as cosmetics, detergents, adhesives, fibers and water treatment.

Claims (1)

In the step of producing an allyl dimethylamine by reacting an aqueous dimethylamine solution and allyl chloride in the presence of an aqueous sodium hydroxide solution, and a method of producing diallyldimethylammonium chloride by reacting the allyldimethylamine and allyl chloride, Separating the sodium chloride by vacuum concentration of the diallyldimethylammonium chloride prepared above at 40 to 60 ° C. and 35 to 45 torr; The separated sodium chloride is separated by the alcohol containing sodium chloride and diallyldimethylammonium chloride by adding C ₁ to C ₃ lower alcohols in a weight ratio of 1 to 3 based on sodium chloride; And Recovering the alcohol by drying the vacuum containing diallyldimethylammonium chloride at 20 to 40 ° C. and 15 to 25 torr; Separation and recovery method of diallyldimethylammonium chloride comprising a.