阅读说明：本技术 一种精制橡胶促进剂mbt的方法 (Method for refining rubber accelerator MBT ) 是由 张颂 刘彬 齐步金 聂言培 单鑫 于 2019-09-09 设计创作，主要内容包括：本发明公开了一种精制橡胶促进剂MBT的方法,属于精细化工领域。本发明将橡胶促进剂MBT粗品溶于碱液中,加入复合氧化剂,搅拌反应1~3小时,过滤得澄清透明的MBT-盐溶液,调节pH至6~7,脱水干燥得浅黄色橡胶促进剂MBT纯品；复合氧化剂由双氧水和双氧水缓释剂组成。本发明方法中双氧水缓释剂有效抑制了双氧水的氧化性,能够把MBT盐溶液中的杂质氧化成不溶于水的杂质而通过过滤或离心去除,同时不会氧化MBT盐溶液,反应一段时间后自动到终点,无需判断终点,也无需担心MBT被氧化成DM影响MBT的质量。本发明方法可有效避免双氧水的局部过氧化及终点不好判断的现象,显著降低了人工劳动强度,同时稳定了产品质量。(The invention discloses a method for refining a rubber accelerator MBT, which belongs to the field of fine chemical engineering.A crude product of the rubber accelerator MBT is dissolved in alkali liquor, a composite oxidant is added, the mixture is stirred and reacts for 1 ~ 3 hours, a clear and transparent MBT-salt solution is obtained by filtering, the pH value is adjusted to 6 ~ 7, and the pure product of the pale yellow rubber accelerator MBT is obtained by dehydration and drying.)

1. A method for refining a rubber accelerator MBT is characterized by dissolving a crude product of the rubber accelerator MBT in alkali liquor at the temperature of 30 ~ 90 ℃, adding a composite oxidant, stirring for reaction for 1 ~ 3 hours, filtering to obtain a clear and transparent MBT-salt solution, dropwise adding an acid liquor into the MBT-salt solution to adjust the pH value to 6 ~ 7, dehydrating and drying to obtain a light yellow MBT pure product of the rubber accelerator, wherein the composite oxidant is composed of hydrogen peroxide and a hydrogen peroxide slow-release agent.

2. A process for refining MBT, a rubber accelerator, as defined in claim 1, wherein: the hydrogen peroxide slow release agent is one or more of sodium silicate, magnesium silicate, polyacrylamide, organic phosphate and ethylene diamine tetraacetic acid.

3. The method for refining the rubber accelerator MBT as claimed in claim 1 or 2, wherein the mass ratio of hydrogen peroxide to the hydrogen peroxide slow-release agent in the composite oxidant is 1000:1 ~ 20:1 calculated by hydrogen peroxide with the mass fraction of 27%.

4. The method for refining the rubber accelerator MBT as claimed in claim 1 or 2, wherein the mass ratio of the hydrogen peroxide to the hydrogen peroxide slow-release agent in the composite oxidant is 100:1 ~ 50:1 calculated by the hydrogen peroxide with the mass fraction of 27%.

5. The method for refining the rubber accelerator MBT as described in claim 1 or 2, wherein the mass ratio of the crude rubber accelerator MBT to the complex oxidizer is 1:2 ~ 3.

6. The method for refining the rubber accelerator MBT as claimed in claim 5, wherein the mass ratio of the crude rubber accelerator MBT to the composite oxidant is 1:2.45 ~ 2.55.55.

7. The method for refining the rubber accelerator MBT as claimed in claim 1 or 2, wherein the mass fraction of the hydrogen peroxide is 1.5% ~ 2.5.5%.

8. The method of refining rubber accelerator MBT as described in claim 1 or 2, wherein the alkali solution is 25% ~ 35% by weight of sodium hydroxide, potassium hydroxide or ammonia water.

9. A method for refining a rubber accelerator MBT as defined in claim 1 or 2, wherein the acid solution is a hydrochloric acid solution or sulfuric acid solution having a mass fraction of 5% ~ 10%.

10. The method of refining rubber accelerator MBT according to claim 1, wherein water is added to form a MBT salt solution with a mass fraction of 2% ~ 10% before adding the complex oxidant.

Technical Field

The invention belongs to the technical field of fine chemical engineering, and particularly relates to a method for refining a rubber accelerator MBT.

Background

The rubber accelerator MBT is a universal accelerator, is widely used for various rubbers, and has a quick vulcanization acceleration effect in natural rubber and general synthetic rubber. Besides, it also has a certain plasticity and anti-ageing property, and can be used as retardant in chloroprene rubber. And derivatives thereof such as: CZ, NS, DZ, NOBS and the like have more excellent rubber vulcanization acceleration performance. The rubber accelerator MBT is easy to disperse in rubber and is pollution-free. The method is mainly used for manufacturing tires, inner tubes, adhesive tapes, rubber shoes, industrial products and the like.

At present, the rubber accelerator MBT is generally produced industrially by a high pressure method, namely aniline, sulfur and carbon disulfide react at high temperature (250-300 ℃) and high pressure (8.0-11.0 Mpa) to obtain crude MBT. The MBT content in the crude product is generally 85-88%, the crude product contains more resin and intermediate products, and the application of the MBT is limited by the existence of impurities, so the crude product MBT can be used as a commodity after being purified, and the purification of the MBT is particularly important.

The current methods for refining MBT are mainly of two types: acid-base method and solvent method.

The solvent method uses an organic solvent (such as one or a plurality of toluene, carbon disulfide, aniline, chlorobenzene, methanol and the like) to extract crude MBT in a liquid-liquid extraction or solid-liquid extraction manner, such as Chinese invention patents with publication numbers of CN102718728A, CN 104031003A, CN 105061357A, CN1687040A, CN101693701A and the like, although the refining of the crude MBT can be realized, the obtained MBT product has low purity and cannot be directly used for rubber vulcanization as commercial grade MBT; when the obtained MBT product is used for a sulfonamide raw material, the product index of a downstream sulfonamide accelerator is influenced.

In the traditional acid-base method, air or oxygen is used as an oxidant, so that high-quality MBT products can be obtained, but a large amount of off-flavor gas is generated in production, and the on-site environment and the occupational health of workers are not facilitated; although the problem of peculiar smell can be solved by directly adopting hydrogen peroxide as an oxidant, as in patent CN102827102A, the reaction end point is not well judged due to strong oxidizing capability of hydrogen peroxide, and the MBT is easy to generate DM, thereby affecting the quality of commercial MBT.

Disclosure of Invention

In order to make up for the deficiencies of the prior art, the invention provides a method for refining a rubber accelerator MBT.

The technical scheme of the invention is as follows:

a process for refining MBT includes such steps as dissolving the crude MBT product in alkali solution at 30 ~ 90 deg.C, adding composite oxidant, stirring for reaction for 1 ~ 3 hr, filtering to obtain clear and transparent MBT-salt solution, dropping acid solution in the MBT-salt solution to regulate pH to 6 ~ 7, dewatering and drying to obtain the light yellow MBT product, and the composite oxidant is composed of hydrogen peroxide and slow-releasing hydrogen peroxide.

Preferably, the hydrogen peroxide slow release agent is one or more of sodium silicate, magnesium silicate, polyacrylamide, organic phosphate and ethylene diamine tetraacetic acid.

The oxydol slow release agent can inhibit the oxidation capacity of oxydol, the oxydol slow release agent is used as a negative catalyst to effectively control the oxidability of oxydol, the composite oxidant can oxidize impurities in the MBT salt solution into water-insoluble impurities to be removed by filtration or centrifugation, and meanwhile, the composite oxidant can not oxidize the MBT salt solution, so that the reaction is automatically finished after a period of time, and end point judgment is not needed.

According to a preferable scheme, the mass ratio of hydrogen peroxide to hydrogen peroxide slow-release agent in the composite oxidant is 1000:1 ~ 20:1, and when the mass ratio of hydrogen peroxide to hydrogen peroxide slow-release agent in the composite oxidant is 1000:1 ~ 20:1, the hydrogen peroxide slow-release agent can play a good negative catalysis role, can inhibit the oxidation of hydrogen peroxide, and can ensure that MBT salt solution cannot be oxidized on the premise that impurities can be oxidized to generate water-insoluble impurities.

Further, the mass ratio of the hydrogen peroxide to the hydrogen peroxide slow-release agent in the composite oxidant is 100:1 ~ 50:1 calculated by hydrogen peroxide with the mass fraction of 27%, and when the mass ratio of the hydrogen peroxide to the hydrogen peroxide slow-release agent in the composite oxidant is 100:1 ~ 50:1, the oxidation reaction time can be ensured not to be too long on the premise that impurities can be oxidized to generate water-insoluble impurities.

Preferably, the mass ratio of the crude rubber accelerator MBT to the composite oxidant is 1:2 ~ 3, impurities can be sufficiently oxidized in the ratio range, and a product with high purity is obtained.

Further, the mass ratio of the crude rubber accelerator MBT to the composite oxidant is 1:2.45 ~ 2.55.55.

Preferably, the mass fraction of the hydrogen peroxide is 1.5% ~ 2.5.5%.

Preferably, the alkali liquor is 25% ~ 35% sodium hydroxide, potassium hydroxide or ammonia water.

Preferably, the acid solution is a hydrochloric acid solution or a sulfuric acid solution with the mass fraction of 5% ~ 10%.

Preferably, before adding the composite oxidant, water is added to form an MBT salt solution with the mass fraction of 2% ~ 10%.

The invention has the beneficial effects that:

in the method, the salt solution of the MBT crude product is oxidized by a composite oxidant consisting of hydrogen peroxide and a hydrogen peroxide slow-release agent, and the hydrogen peroxide slow-release agent effectively inhibits the oxidability of hydrogen peroxide; by adopting the composite oxidant, impurities in the MBT salt solution can be oxidized into water-insoluble impurities and removed by filtration or centrifugation, and meanwhile, the composite oxidant can not oxidize the MBT salt solution and automatically reaches the end point after reacting for a period of time, so that the end point does not need to be judged, and the quality of MBT is not influenced by oxidation of MBT into DM.

The method can effectively avoid the phenomena of local peroxidation of hydrogen peroxide and poor judgment of the end point, obviously reduce the labor intensity of workers, stabilize the product quality and improve the safety of the whole process flow.

The method saves the end point judgment process, can ensure that the MBT can not be oxidized into DM, has simple process flow, obviously improves the purification efficiency, obviously improves the quality of the refined MBT, ensures that the product purity is more than 98 percent, and is very suitable for industrial production.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a process flow diagram of the method for refining a rubber accelerator MBT according to the present invention.

Detailed Description