CN1417185A

CN1417185A - Alkaline anionic exchange resin process of refining and purifying 1,3-propylene glycol

Info

Publication number: CN1417185A
Application number: CN 01132145
Authority: CN
Inventors: 徐泽辉; 郭世卓; 王佩琳
Original assignee: Sinopec Shanghai Petrochemical Co Ltd
Current assignee: Sinopec Shanghai Petrochemical Co Ltd
Priority date: 2001-11-08
Filing date: 2001-11-08
Publication date: 2003-05-14
Anticipated expiration: 2021-11-08
Also published as: CN1168692C

Abstract

The process of refining and purifying 1,3-propylene glycol includes treating 1,3-propylene glycol material with residual aldehyde group matters with alkaline anionic exchange resin at 30-90 deg.c, reduced pressure distillation at 121-149 deg.c, and condensation of distillate to obtain high-purity 1,3-propylene glycol. The alkaline anionic exchange resin is spherical grains with surface functional group -N+(CH3)OH- and of 0.315-1.25 mm size, specific surface area 1-20 sq m/g and pore volume 0.1-10 ml/g. The treating process may be performed in either a fixed bed reactor or a suspension bed reactor. The process of the present invention can reduce the residual aldehyde group matter content in 1,3-propylene glycol produced through hydrating acraldehyde to below 10 ppm.

Description

Method for refining and purifying 1, 3-propylene glycol by using strongly basic anion exchange resin

Technical Field

The invention relates to refining and purifying of 1, 3-propylene glycol, in particular to a method for removing trace residual aldehyde substances in 1, 3-propylene glycol.

Background

1, 3-propanediol is a versatile compound that, in addition to being useful in the production of polyurethanes and cyclic compounds, is also a major monomer for 1, 3-propanediol terephthalate fibers. Although poly (1, 3-trimethylene terephthalate) fibers are a polyester variety with excellent performance, and have been produced in the 50 s, the 1, 3-trimethylene terephthalate fibers have been in a state of stagnation for many years because 1, 3-trimethylene glycol has not been commercialized. In recent years, with the success of the industrial production of 1, 3-propanediol, the development and application of poly (1, 3-propanediol terephthalate) fibers are receiving more attention. Among them, the hydration of acrolein to produce 3-hydroxypropanal and the subsequent hydrogenation to produce 1, 3-propanediol is one of the successful commercial routes.

In the production of 1, 3-propanediol by the acrolein hydration route, the hydration product of acrolein contains unconverted acrolein and hydration by-products in addition to 3-hydroxypropanal. Although the residual aldehyde groups can be reduced by hydrogenation, even if the product is substantially free of residual aldehyde species, using relatively severe hydrogenation conditions, it is common to produce 1, 3-propanediol by the generally available commercial acrolein hydration route to produce about 500ppm of residual aldehyde species in the product. If the 1, 3-propanediol is used for producing the poly (1, 3-trimethylene terephthalate), various quality indexes of poly (1, 3-trimethylene terephthalate) fiber products can be influenced, wherein the influence on the dyeing effect and the dyeing stability of fiber dyeing is particularly obvious. Therefore, it is very necessary to remove trace residual aldehyde substances in the 1, 3-propanediol before the 1, 3-propanediol is used for preparing the poly (1, 3-propanediol terephthalate).

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for removing trace residual aldehyde group substances in 1, 3-propanediol, which adopts a simpler process to reduce the residual aldehyde group content of the 1, 3-propanediol to below 50ppm so as to solve the problems in the prior art.

The technical problem to be solved by the invention is realized by the following technical scheme.

Treating 1, 3-propanediol containing residual aldehyde group substances by using strong-base anion exchange resin, wherein the treatment temperature is 30-90 ℃, the treated material is subjected to reduced pressure distillation at the temperature of 121-149 ℃, and distillate is condensed to obtain high-purity 1, 3-propanediol, and the strong-base anion exchange resin has surface functional groups: -N⁺(CH₃)OH^-。

The strongly basic anion exchange resin is spherical granular, and the granularity is 0.315-1.25 mm; the specific surface area is 1-20 m²A ratio of 2 to 10 m/g is preferable²(ii)/g; the pore volume is 0.1 to 10ml/g, preferably 0.2 to 5 ml/g. The best treatment temperature is 40-70 ℃.

The treatment of the 1, 3-propanediol with the strongly basic anion exchange resin can be carried out in a fixed bed reactor, wherein the space velocity is controlled to be 1-6 hr^-1Preferably 2 to 5hr^-1(ii) a Or in a suspension bed reactor, wherein the addition amount of the strongly basic anion exchange resin is 0.1-10%, and the best addition amount is 2-9%.

Based on the above analysis, the inventor has studied a large number of solid catalysts with certain acid/alkali, and selected molecular sieves, diatomaceous earth and strongly basic anion exchange resins to perform experiments.

The reaction mechanism of aldehyde groups on strongly basic anion exchange resins is generally believed to be the following:

(1)

(2)

(3) the aldehyde containing active α -H can continue to react at the basic central position, and can also be subjected to condensation reaction with other aldehyde containing no α -H, and finally a substance with high molecular weight and high boiling point is generated.

In the reaction conditions, the treatment temperature has great influence on the content of aldehyde group substances in the product, and the aldehyde group is removed more completely at higher temperature. However, since the 1, 3-propanediol is subjected to intermolecular or intramolecular dehydration reaction in an acidic environment, the treatment temperature has an optimal range, and experiments show that the treatment temperature can achieve better effects at 30-90 ℃, wherein the optimal treatment temperature is 40-70 ℃.

The 1, 3-propanediol produced by the general acrolein hydration route can generally reduce the content of residual aldehyde substances in the 1, 3-propanediol to below 10ppm by adopting the method provided by the invention. The method provided by the invention has simple process and much lower cost than the intensified hydrogenation condition, so the positive effect is very obvious.

Detailed Description

The invention will now be further described by way of a series of examples in which:

the strongly basic anion exchange resin used has surface functional groups: -N⁺(CH₃)OH^-The particle size is 0.315-1.25 mm, and the specific surface area is 2-10 m²(ii)/g; the pore volume is 0.2-5 ml/g. [ examples 1 to 7]

Preheating 1, 3-propylene glycol solution containing residual aldehyde group substances to 30-90 ℃, pumping into a 500 x 30mm reactor filled with strong-base anion exchange resin by a pump for reaction, and controlling the space velocity to be 4-5 hr^-1. Distilling the treated 1, 3-propylene glycol, wherein the highest temperature of the kettle bottom is 149 ℃, the highest temperature of the tower top is 121 ℃, and the vacuum degree is 20 mmHg. The treatment temperatures and treatment effects used in the examples are shown in Table 1. [ examples 8 to 14]

Preheating 1, 3-propylene glycol solution containing residual aldehyde group substances to 60 ℃, pumping into a 500X 30mm reactor filled with strongly basic anion exchange resin by using a pump for reaction, and distilling the treated 1, 3-propylene glycol, wherein the highest temperature of the kettle bottom is 149 ℃, the highest temperature of the tower top is 121 ℃, and the vacuum degree is 20 mmHg. The space velocity and the effect of the treatment used in the examples are shown in Table 2. [ examples 15 to 21]

1, 3-propylene glycol containing residual aldehyde group substances is added into a kettle type reactorSolutions and kitsAnd (3) heating the required amount of strongly basic anion exchange resin to 30-90 ℃, reacting for 1 hour, and distilling, wherein the highest temperature of the kettle bottom is 149 ℃, the highest temperature of the tower top is 121 ℃, and the vacuum degree is 20 mmHg. The specific amount of catalyst used and the treatment effect are shown in table 3. Table 1.

	Temperature of treatment (℃)	Aldehyde group content of raw material (ppm)	Aldehyde group content after treatment (ppm)	Yield of (％)
	Temperature of treatment (℃)	Aldehyde group content of raw material (ppm)	Aldehyde group content after treatment (ppm)	Yield of (％)	Example 1	30	2000	30	99％
Example 2	40	2000	20	99％	Example 1	30	2000	30	99％
Example 2	40	2000	20	99％	Example 3	50	2000	＜10	99％
Example 4	60	2000	＜10	99％	Example 3	50	2000	＜10	99％
Example 4	60	2000	＜10	99％	Example 5	70	2000	＜10	98％
Example 6	80	2000	＜10	98％	Example 5	70	2000	＜10	98％
Example 6	80	2000	＜10	98％	Example 7	90	2000	＜10	97％

Table 2.

	Airspeed (hr^-1)	Aldehyde group content of raw material (ppm)	Aldehyde group content after treatment (ppm)	Yield of (％)
	Airspeed (hr^-1)	Aldehyde group content of raw material (ppm)	Aldehyde group content after treatment (ppm)	Yield of (％)	Example 8	1	2000	＜10	99％
Example 9	1.5	2000	＜10	99％	Example 8	1	2000	＜10	99％
Example 9	1.5	2000	＜10	99％	Example 10	2	2000	＜10	99％
Example 11	4	2000	＜10	99％	Example 10	2	2000	＜10	99％
Example 11	4	2000	＜10	99％	Example 12	4.5	2000	＜10	99％
Example 13	5	2000	＜10	99％	Example 12	4.5	2000	＜10	99％
Example 13	5	2000	＜10	99％	Example 14	6	2000	13	99％

Table 3.

	Amount of catalyst (％)	Aldehyde group content of raw material (ppm)	Aldehyde group content after treatment (ppm)	Yield of (％)
	Amount of catalyst (％)	Aldehyde group content of raw material (ppm)	Aldehyde group content after treatment (ppm)	Yield of (％)	Example 15	0.1	2000	30	99％
Example 16	1	2000	15	99％	Example 15	0.1	2000	30	99％
Example 16	1	2000	15	99％	Example 17	1.5	2000	13	99％
Example 18	2	2000	＜10	99％	Example 17	1.5	2000	13	99％
Example 18	2	2000	＜10	99％	Example 19	6	2000	＜10	99％
Example 20	7	2000	＜10	99％	Example 19	6	2000	＜10	99％
Example 20	7	2000	＜10	99％	Example 21	9	2000	＜10	99％

Claims

1. A method for refining and purifying 1, 3-propanediol comprises the steps of treating 1, 3-propanediol containing residual aldehyde substances by using strongly basic anion exchange resin at the treatment temperature of 30-90 ℃, carrying out reduced pressure distillation on the treated material at the temperature of 121-149 ℃, and condensing distillate to obtain high-purity 1, 3-propanediol, wherein the strongly basic anion exchange resin has surface functional groups: -N⁺(CH₃)OH^-。

2. The method for refining and purifying 1, 3-propanediol according to claim 1, wherein said strongly basic anion exchange resin is spherical, granular, has a particle size of 0.315-1.25 mm and a specific surface area of 1-20 m²The pore volume is 0.1-10 ml/g.

3. The method for refining and purifying 1, 3-propanediol according to claim 2, wherein the specific surface area of said strongly basic anion exchange resin is 2 to 10m²The pore volume is 0.2 to 5 ml/g.

4. The method for refining and purifying 1, 3-propanediol according to claim 1 or 2, wherein the treatment temperature is 40 to 70 ℃.

5.The method of claim 1 or 2, wherein the treatment is carried out in a fixed bed reactor at a space velocity of 1hr^-1～6hr^-1。

6. The purification process of claim 5, 1, 3-propylene glycol, characterized in that said space velocity is 2-5 hr^-1。

7. The method for refining and purifying 1, 3-propanediol according to claim 1 or 2, characterized in that the treatment process is carried out in a suspension bed reactor, and the amount of the strongly basic anion exchange resin is 0.1-10% of the weight percentage of the strongly basic anion exchange resin in the reaction solution.

8. The method for refining and purifying 1, 3-propanediol according to claim 7, wherein the amount of the strongly basic anion exchange resin is 2-9% by weight of the strongly basic anion exchange resin in the reaction solution.