阅读说明：本技术 一种降低环状三羟甲基丙烷缩甲醛色号的处理方法 (Treatment method for reducing color number of cyclic trimethylolpropane formal ) 是由 蒋国强 吴晓明 黄小磊 赵跃 缪世军 梁国成 袁庆庆 夏海峰 周国君 黄路强 于 2021-06-03 设计创作，主要内容包括：本发明公开了一种降低环状三羟甲基丙烷缩甲醛色号的处理方法,它涉及精细化学品生产技术领域。具体包括以下步骤：加入还原剂反应：向反应釜中加入高色号的环状三羟甲基丙烷缩甲醛与还原剂,开启搅拌进行反应；真空脱水：反应完成后在真空条件下进行脱水,脱水至无水采出；成品采出：脱水完成后提高真空度,精馏进行成品采出,得到低色号的环状三羟甲基丙烷缩甲醛。本发明的优点在于：采用还原剂与高色号的环状三羟甲基丙烷缩甲醛反应,先升温脱水,然后再精馏采出环状三羟甲基丙烷缩甲醛,可降低环状三羟甲基丙烷缩甲醛的色号,既节约生产成本又避免三废处理负担；使用装置简单,将反应与精馏融为一体,减少操作步骤,反应周期短、能耗低。(The invention discloses a treatment method for reducing the color number of cyclic trimethylolpropane formal, and relates to the technical field of fine chemical production. The method specifically comprises the following steps: adding a reducing agent for reaction: adding high-color-number cyclic trimethylolpropane formal and a reducing agent into a reaction kettle, and starting stirring to react; vacuum dehydration: after the reaction is finished, dehydrating under a vacuum condition until no water is extracted; and (3) finished product extraction: and after dehydration, improving the vacuum degree, rectifying to extract a finished product, and obtaining the low-color-number cyclic trimethylolpropane formal. The invention has the advantages that: the reducing agent is adopted to react with the cyclic trimethylolpropane formal with high color number, the cyclic trimethylolpropane formal is extracted by heating and dehydrating firstly and then rectifying, the color number of the cyclic trimethylolpropane formal can be reduced, the production cost is saved, and the three-waste treatment burden is avoided; the using device is simple, the reaction and the rectification are integrated, the operation steps are reduced, the reaction period is short, and the energy consumption is low.)

1. A treatment method for reducing the color number of cyclic trimethylolpropane formal is characterized by comprising the following steps: the method comprises the following steps:

s1, adding a reducing agent for reaction: adding high-color-number cyclic trimethylolpropane formal and a reducing agent into a reaction kettle, and starting stirring to react;

s2, vacuum dehydration: after the reaction is finished, dehydrating under a vacuum condition until no water is extracted;

s3, finished product extraction: and after dehydration, improving the vacuum degree, rectifying to extract a finished product, and obtaining the low-color-number cyclic trimethylolpropane formal.

2. The method as claimed in claim 1, wherein the color number of the cyclic trimethylolpropane formal is reduced by the following steps: in the step S1, the mass ratio of the high-color-number cyclic trimethylolpropane formal to the reducing agent is 1000: 1-5, the reaction temperature is increased to 85-95 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

3. The method according to claim 1 or 2, wherein the color number of the cyclic trimethylolpropane formal is reduced by: in step S1, the reducing agent is one or more of hypophosphorous acid, sodium hypophosphite, oxalic acid, and sodium oxalate.

4. The method as claimed in claim 1, wherein the color number of the cyclic trimethylolpropane formal is reduced by the following steps: in the step S2, the vacuum degree in the reaction kettle is maintained at-800 to-1000 Pa during dehydration, and the dehydration temperature is 125-130 ℃.

5. The method as claimed in claim 1, wherein the color number of the cyclic trimethylolpropane formal is reduced by the following steps: in the step S3, after the dehydration is completed, the vacuum degree is increased to-0.095 to-0.098 MPa, and the extraction temperature is 130-145 ℃.

Technical Field

The invention relates to the technical field of fine chemical production, in particular to a treatment method for reducing the color number of cyclic trimethylolpropane formal.

Background

The cyclic trimethylolpropane formal has a chemical name of 5-ethyl-5-hydroxymethyl-1, 3-dioxane, is monocyclic monohydric alcohol, is colorless liquid, has small smell and excellent performance, is suitable for producing radiation curing monomer ester, is a monofunctional group reactive diluent with low shrinkage and good reaction activity, and can be used for preparing special alcohol of acrylate monoester monomer with low peculiar smell and high glass transition temperature. As a mono-monomer, it can improve the adhesion of coatings for plastics, ceramics, metals and other hard substrates. The cyclic trimethylolpropane formal is also suitable for lubricant additives, cutting fluid additives, high-boiling point solvents and chemical building materials. The cyclic trimethylolpropane formal and its esters as high-quality diluent and additive have certain influence on its performance, such as purity and chromaticity.

In the actual production process, a certain amount of cyclic trimethylolpropane formal with a color number higher than the market demand is generated, the high-color cyclic trimethylolpropane formal influences the service performance of the cyclic trimethylolpropane formal, and if the cyclic trimethylolpropane formal is abandoned, the production cost is increased, and the three-waste treatment burden is increased.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a treatment method for reducing the color number of cyclic trimethylolpropane formal, which can solve the problems that the service performance of high-color cyclic trimethylolpropane formal generated in the prior art is influenced, the direct treatment increases the production cost and the burden of three-waste treatment.

In order to solve the technical problems, the technical scheme of the invention is as follows: the method comprises the following steps:

s1, adding a reducing agent for reaction: adding high-color-number cyclic trimethylolpropane formal and a reducing agent into a reaction kettle, and starting stirring to react;

s2, vacuum dehydration: after the reaction is finished, dehydrating under a vacuum condition until no water is extracted;

s3, finished product extraction: and after dehydration, improving the vacuum degree, rectifying to extract a finished product, and obtaining the low-color-number cyclic trimethylolpropane formal.

Further, in the step S1, the mass ratio of the high-color-number cyclic trimethylolpropane formal to the reducing agent is 1000: 1-5, the reaction temperature is increased to 85-95 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

Further, in step S1, the reducing agent is one or more of hypophosphorous acid, sodium hypophosphite, oxalic acid, and sodium oxalate.

Further, in the step S2, the vacuum degree in the reaction kettle is maintained at-800 to-1000 Pa during dehydration, and the dehydration temperature is 125-130 ℃.

Further, in the step S3, after the dehydration is completed, the vacuum degree is increased to-0.095 to-0.098 MPa, and the extraction temperature is 130-145 ℃.

The invention has the advantages that: the method has the advantages that the reducing agent is adopted to react with the high-color-number cyclic trimethylolpropane formal, the cyclic trimethylolpropane formal is heated and dehydrated under the low vacuum condition, and then the low-color-number cyclic trimethylolpropane formal is obtained through rectification under the high vacuum condition, so that the color number of the cyclic trimethylolpropane formal can be reduced from No. 50-60 to No. 10-15, the product quality is improved, the added value of the product is improved, the application field of the product is expanded, a quality foundation is provided for opening a high-end market, the production cost is saved, and the burden of three-waste treatment is avoided;

the device provided by the invention is simple, integrates reaction and rectification, reduces operation steps, and has the advantages of short reaction period, high speed and low energy consumption.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments. The following examples are presented to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the scope of the embodiments described herein.

Example 1:

the specific implementation mode adopts the following technical scheme:

s1, adding a reducing agent for reaction: 2301g of cyclic trimethylolpropane formal with the color number of 50 and 2.5g of hypophosphorous acid serving as a reducing agent are added into a reaction kettle, stirring is started to carry out reaction, the reaction temperature is raised to 85 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

S2, vacuum dehydration: after the reaction is finished, dehydrating under the condition of low vacuum, wherein the vacuum degree is-800 to-1000 Pa, the dehydration temperature is 125 ℃, and dehydrating until the water is basically extracted;

s3, finished product extraction: after dehydration, the vacuum degree is improved to-0.095 to-0.098 MPa, and the finished product is extracted by rectification at the extraction temperature of 130 ℃ to obtain the cyclic trimethylolpropane formal with the color number of 10.

Example 2:

s1, adding a reducing agent for reaction: 2214g of cyclic trimethylolpropane formal with the color number of 60 and 4.0g of hypophosphorous acid serving as a reducing agent are added into a reaction kettle, stirring is started to carry out reaction, the reaction temperature is raised to 85 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

S2, vacuum dehydration: after the reaction is finished, dehydrating under the condition of low vacuum, wherein the vacuum degree is-800 to-1000 Pa, the dehydration temperature is 125 ℃, and dehydrating until the water is basically extracted;

s3, finished product extraction: after dehydration, the vacuum degree is improved to-0.095 to-0.098 MPa, and the finished product is extracted by rectification at the extraction temperature of 130 ℃ to obtain the cyclic trimethylolpropane formal with the color number of 10.

Example 3:

s1, adding a reducing agent for reaction: 2271g of cyclic trimethylolpropane formal with the color number of 50 and 1.5g of hypophosphorous acid serving as a reducing agent are added into a reaction kettle, stirring is started to carry out reaction, the reaction temperature is raised to 85 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

S2, vacuum dehydration: after the reaction is finished, dehydrating under the condition of low vacuum, wherein the vacuum degree is-800 to-1000 Pa, the dehydration temperature is 125 ℃, and dehydrating until the water is basically extracted;

s3, finished product extraction: after dehydration, the vacuum degree is improved to-0.095 to-0.098 MPa, and the finished product is extracted by rectification at the extraction temperature of 130 ℃ to obtain the cyclic trimethylolpropane formal with the color number of 15.

The mass ratio of the cyclic trimethylolpropane formal of examples 1 to 3 to the reducing agent hypophosphorous acid and the color number of the produced finished product reduced were compared and shown in Table 1.

Table 1: examples 1-3 comparison of color number reduction of finished products produced with different mass ratios of cyclic trimethylolpropane formal and a reducing agent hypophosphorous acid

Item	Example 1	Example 2	Example 3
				Reaction dosage of cyclic trimethylolpropane formal	2301g	2214g	2271g
Reaction dosage of hypophosphorous acid as reducing agent	2.5g	4.0g	1.5g
				Mass ratio of cyclic trimethylolpropane formal to hypophosphorous acid as reducing agent	1000:1.09	1000:1.81	1000:0.66
Reduced color number of produced finished product	No. 50 to No. 10	No. 60 to No. 10	No. 50 to No. 15

As can be seen from the above table, the color number of the cyclic trimethylolpropane formal can be effectively reduced by the treatment method of the invention, and the reduction value of the color number of the cyclic trimethylolpropane formal can be seen as being influenced by the dosage of the reducing agent hypophosphorous acid in the examples 1 to 3, and the example 2 is the best example.

Example 4:

s1, adding a reducing agent for reaction: 2214g of cyclic trimethylolpropane formal with the color number of 60 and 4.0g of hypophosphorous acid serving as a reducing agent are added into a reaction kettle, stirring is started to carry out reaction, the reaction temperature is raised to 90 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

S2, vacuum dehydration: after the reaction is finished, dehydrating under the condition of low vacuum, wherein the vacuum degree is-800 to-1000 Pa, the dehydration temperature is 127 ℃, and dehydrating until the water is basically removed;

s3, finished product extraction: after dehydration, the vacuum degree is improved to-0.095 to-0.098 MPa, and the finished product is extracted by rectification at the extraction temperature of 140 ℃ to obtain the cyclic trimethylolpropane formal with the color number of 10.

Example 5:

s1, adding a reducing agent for reaction: 2214g of cyclic trimethylolpropane formal with the color number of 60 and 4.0g of hypophosphorous acid serving as a reducing agent are added into a reaction kettle, stirring is started to carry out reaction, the reaction temperature is raised to 95 ℃, the reaction time is 0.5-1h, and the stirring speed is 50 r/min.

S2, vacuum dehydration: after the reaction is finished, dehydrating under the condition of low vacuum, wherein the vacuum degree is-800 to-1000 Pa, the dehydration temperature is 130 ℃, and dehydrating until the water is basically extracted;

s3, finished product extraction: after dehydration, the vacuum degree is improved to-0.095 to-0.098 MPa, the finished product is extracted by rectification, the extraction temperature is 145 ℃, and the cyclic trimethylolpropane formal with the color number of 10 is obtained.

The reaction temperatures, dehydration temperatures, withdrawal temperatures, and color numbers of the withdrawn finished products of examples 2, 4, and 5 were compared, see table 2.

Table 2: examples 2, 4 and 5 color number comparison of finished products produced using different reaction temperatures, dehydration temperatures, production temperatures

Item	Example 2	Example 4	Example 5
				Reaction temperature	85℃	90℃	95℃
Temperature of dehydration	125℃	127℃	130℃
				Temperature of production	130℃	140℃	145℃
Finished product color number	Number 10	Number 10	Number 10

As can be seen from the above table, in examples 2, 4 and 5, the reaction temperature, dehydration temperature and extraction temperature are not significantly changed in the reduction of the color number of the cyclic trimethylolpropane formal, and example 2 is the most preferable example in view of energy consumption.

According to the invention, the reducing agent is adopted to react with the high-color-number cyclic trimethylolpropane formal, the cyclic trimethylolpropane formal is heated and dehydrated under the low vacuum condition, and then the low-color-number cyclic trimethylolpropane formal is obtained through rectification under the high vacuum condition, so that the color number of the cyclic trimethylolpropane formal can be reduced, the product quality is improved, the production cost is saved, and the three-waste treatment burden is avoided; the device provided by the invention is simple, integrates reaction and rectification, reduces operation steps, and has the advantages of short reaction period, high speed and low energy consumption.

The foregoing shows and describes the general principles and features of the present invention, together with the advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.