阅读说明：本技术 一种制备低水解氯1，5-戊二异氰酸酯的方法 (Method for preparing low-hydrolysis chlorine 1, 5-pentanediisocyanate ) 是由 刘耀宗 王进军 梁睿渊 滕志君 常有才 杨英朝 赵勃溶 吕改芳 魏武域 张建强 于 2020-12-02 设计创作，主要内容包括：本发明公开了一种制备低水解氯1,5-戊二异氰酸酯的方法,具体步骤是：先在低温下将光气溶于溶剂中直至饱和,继续通光气的同时,将生物基1,5-戊二胺和溶剂的混合溶液通过计量泵加入到光气溶液中,滴加完成后,程序升温,控制反应温度和时间,得到含有1,5-戊二异氰酸酯的光化液,反应完成后,减压蒸馏脱除溶剂,继续减压蒸馏可得到无色液体,即1,5-戊二异氰酸酯。本发明的有益效果是得到低水解氯(小于50 ppm)的1,5-戊二异氰酸酯产品,可直接用于下游应用,操作过程简单,适合于工业化生产。(The invention discloses a method for preparing low-hydrolysis chlorine 1, 5-pentamethylene diisocyanate, which comprises the following specific steps: dissolving phosgene in a solvent at a low temperature until the phosgene is saturated, adding a mixed solution of bio-based 1, 5-pentanediamine and the solvent into the phosgene solution through a metering pump while continuing introducing the phosgene, carrying out temperature programming after finishing the dropwise addition, controlling the reaction temperature and the reaction time to obtain a photochemical liquid containing 1, 5-pentanediisocyanate, removing the solvent through reduced pressure distillation after the reaction is finished, and continuing the reduced pressure distillation to obtain a colorless liquid, namely the 1, 5-pentanediisocyanate. The invention has the advantages that the 1, 5-pentamethylene diisocyanate product with low hydrolytic chlorine (less than 50 ppm) can be directly used for downstream application, the operation process is simple, and the invention is suitable for industrial production.)

1. A method for preparing low-hydrolysis chlorine 1, 5-pentamethylene diisocyanate is characterized in that bio-based 1, 5-pentamethylene diamine is used as a raw material and is prepared by a direct phosgenation method, and the method comprises the following specific steps:

a. controlling the reaction kettle at the temperature of-10-30 ℃, introducing a solvent into the reaction kettle, and introducing phosgene to dissolve in the solvent until the reaction kettle is saturated;

b. adding the mixed solution of the bio-based 1, 5-pentanediamine and the solvent into the phosgene solution through a metering pump while continuing to introduce phosgene into the reaction kettle for carrying out a luminescence reaction to generate carbamoyl chloride, wherein the reaction temperature is 10-40 ℃, and the reaction time is 1-4 hours;

c. continuously introducing phosgene, heating to 50-100 ℃ for photochemical reaction for 0.5-3 h, and removing impurities of the tetrahydrochysene piperidine and the carbamyl chloride in the bio-based 1, 5-pentanediamine through reaction;

d. continuously introducing phosgene, continuously heating to 100-200 ℃ for carrying out a thermo-optic reaction, converting carbamoyl chloride into 1, 5-pentamethylene diisocyanate until the photochemical solution is clear and transparent, and finishing the reaction;

e. phosgene removal and solvent removal are carried out on the photochemical liquid containing the 1, 5-pentamethylene diisocyanate, and the qualified 1, 5-pentamethylene diisocyanate product is obtained by reduced pressure distillation.

2. The process for preparing pentanediisocyanate with low hydrolysis rate as claimed in claim 1, wherein: in the step a, the mass of the solvent is 0.3-0.7 time of the total mass of the solvent in the whole reaction process.

3. The process for preparing pentanediisocyanate with low hydrolysis rate as claimed in claim 1, wherein: the mass ratio of the total amount of phosgene used in the steps a, b, c and d to the total amount of the bio-based 1, 5-pentanediamine is 20:1-10:1, and the mass ratio of the bio-based 1, 5-pentanediamine to the total amount of the solvent in the whole reaction process is 1:5-1: 20.

4. The method for preparing low hydrolyzed chloro-1, 5-pentanediol di-isocyanate according to claim 1, wherein the solvent is any one of o-dichlorobenzene, diethyl isophthalate, amyl acetate or methyl salicylate.

Technical Field

The invention belongs to the field of chemical synthesis, and relates to a method for synthesizing low-hydrolysis chlorine 1, 5-pentanediisocyanate by a direct phosgenation method.

Background

The polyurethane material prepared from the aliphatic isocyanate has excellent mechanical property, outstanding chemical stability and excellent weather resistance, and is widely applied to high-grade building exterior wall coatings, automobile coatings, product shell coatings, industrial equipment pipelines, heat-insulating materials, foamed plastics, synthetic fibers, coatings, solid elastomers and light industrial products closely related to people's life, such as shoes, synthetic leather, heat-insulating materials of refrigerators, waterproof materials and the like. Compared with aromatic isocyanate MDI and TDI, the aliphatic isocyanate has more excellent performance and lower toxicity, and is mainly used for the production of high-end or special polyurethane products. With the increasing maturity of production technology and the upgrading of the market demand for polyurethane materials, the demand for aliphatic isocyanates is driven to show a very rapid increase.

1, 5-Pentamethylene Diisocyanate (PDI) is aliphatic isocyanate, has yellowing resistance, and is used for manufacturing yellowing-resistant polyurethane coatings, printing ink and artificial leather in the form of biuret and trimer. Since the structure and chemical properties are similar to those of HDI and the carbon content is higher, there is a possibility of applying to downstream products instead of HDI. In addition, the raw material PDA of the PDI product can be prepared by adopting a biological method, so that the defects of complex HDA process and high technical difficulty of HDI raw material are overcome, no industrial production device of 1, 5-pentamethylene diisocyanate exists internationally at present, and the synthesis research and the industrial development of the 1, 5-pentamethylene diisocyanate will attract extensive attention along with the construction of domestic PDA production devices by adopting the biological method.

The patent CN 103347852A of Mitsui chemical corporation discloses a research on direct photochemical synthesis or salt formation of 1, 5-pentamethylene diisocyanate from bio-based pentamethylene diamine, and reports that 1, 5-pentamethylene diisocyanate prepared by a biological method contains impurities such as tetrahydropyridine, so that the 1, 5-pentamethylene diisocyanate product contains acyl chloride compounds, the index of the hydrolyzed chlorine is higher, the index requirement of the HDI equivalent product cannot be met, and downstream application is directly influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior treatment technology and provide an industrially feasible method for preparing low-hydrolysis chlorine 1, 5-pentanediisocyanate.

In order to achieve the purpose, the invention adopts the technical scheme that: a method for preparing low-hydrolysis chlorine 1, 5-pentamethylene diisocyanate is characterized in that bio-based 1, 5-pentamethylene diamine is used as a raw material and is prepared by a direct phosgenation method, and the method comprises the following specific steps:

a. controlling the reaction kettle at the temperature of-10-30 ℃, introducing a solvent into the reaction kettle, and introducing phosgene to dissolve in the solvent until the reaction kettle is saturated;

b. adding the mixed solution of the bio-based 1, 5-pentanediamine and the solvent into the phosgene solution through a metering pump while continuing to introduce phosgene into the reaction kettle for carrying out a luminescence reaction to generate carbamoyl chloride, wherein the reaction temperature is 10-40 ℃, and the reaction time is 1-4 hours;

c. continuously introducing phosgene, heating to 50-100 ℃ for photochemical reaction for 0.5-3 h, and removing impurities of the tetrahydrochysene piperidine and the carbamyl chloride in the bio-based 1, 5-pentanediamine through reaction;

d. continuously introducing phosgene, continuously heating to 100-200 ℃ for carrying out a thermo-optic reaction, converting carbamoyl chloride into 1, 5-pentamethylene diisocyanate until the photochemical solution is clear and transparent, and finishing the reaction;

e. phosgene removal and solvent removal are carried out on the photochemical liquid containing the 1, 5-pentamethylene diisocyanate, and the qualified 1, 5-pentamethylene diisocyanate product is obtained by reduced pressure distillation.

In the step a, the mass of the solvent is 0.3-0.7 time of the total mass of the solvent in the whole reaction process.

The mass ratio of the total amount of phosgene used in the steps a, b, c and d to the total amount of the bio-based 1, 5-pentanediamine is 20:1-10:1, and the mass ratio of the bio-based 1, 5-pentanediamine to the total amount of the solvent in the whole reaction process is 1:5-1: 20.

The solvent is any one of o-dichlorobenzene, diethyl isophthalate, amyl acetate or methyl salicylate.

The invention has the beneficial effects that: the method for synthesizing the 1, 5-pentamethylene diisocyanate is optimized, the photochemical synthesis reaction temperature and reaction time are changed, the 1, 5-pentamethylene diisocyanate product with low hydrolytic chlorine (less than 50 ppm) is obtained by product refining, the problem that the product downstream application of the 1, 5-pentamethylene diisocyanate product prepared from the bio-based 1, 5-pentamethylene diamine is influenced due to overhigh hydrolytic chlorine is solved, the operation process is simple, and the method is suitable for industrial production.

Detailed Description

The principles and features of the present invention are further illustrated by the following examples, which are provided for the purpose of illustration only and are not intended to limit the scope of the invention.

Example 1:

adding 4kg of diethyl isophthalate into a 20L glass reaction kettle, introducing gaseous phosgene, after phosgene is dissolved and saturated, uniformly mixing 1 kg of 1, 5-pentanediamine and 6 kg of diethyl isophthalate, adding the solution into the glass reaction kettle by using a metering pump at the flow rate of 50 mL/min, continuously introducing the gaseous phosgene, controlling the reaction temperature to be 10-30 ℃, and continuously reacting for 1 h after dropwise addition is finished to finish the luminescence reaction. Then raising the reaction temperature to 50-100 ℃ for 3 h, and continuing raising the temperature to 130-200 ℃ for reaction until the photochemical solution is clear and transparent, and finishing the reaction. Phosgene removal, solvent removal and product refining are carried out on the photochemical solution to obtain a qualified 1, 5-pentamethylene diisocyanate product, the product yield is 70 percent, and the content of hydrolytic chlorine is 48 ppm.

Example 2:

adding 5 kg of o-dichlorobenzene into a 20L glass reaction kettle, introducing gaseous phosgene, after phosgene is dissolved and saturated, uniformly mixing 1 kg of 1, 5-pentanediamine and 8 kg of o-dichlorobenzene, adding the solution into the glass reaction kettle by using a metering pump at the flow rate of 40 mL/min, continuously introducing the gaseous phosgene, controlling the reaction temperature to be 10-40 ℃, and continuously reacting for 0.5 h after the dropwise addition is finished to finish the cold amination reaction. Then raising the reaction temperature to 60-100 ℃ for 1 h, and continuing raising the temperature to 140-200 ℃ for reaction until the photochemical solution is clear and transparent, and finishing the reaction. Phosgene removal, solvent removal and product refining are carried out on the photochemical solution to obtain a qualified 1, 5-pentamethylene diisocyanate product, the product yield is 73%, and the content of hydrolytic chlorine is 42 ppm.

Example 3:

adding 6 kg of amyl acetate into a 20L glass reaction kettle, introducing gaseous phosgene, after phosgene is dissolved and saturated, uniformly mixing 1 kg of 1, 5-pentanediamine and 2kg of amyl acetate, adding the solution into the glass reaction kettle by using a metering pump according to the flow rate of 50 mL/min, continuously introducing the gaseous phosgene, controlling the reaction temperature to be 20-40 ℃, and continuously reacting for 1 h after the dropwise addition is finished to finish the luminescence reaction. Then the reaction temperature is increased to 55-95 ℃ for 2 h, the temperature is continuously increased to 130-180 ℃ for reaction until the photochemical solution is clear and transparent, and the reaction is finished. Phosgene removal, solvent removal and product refining are carried out on the photochemical solution to obtain a qualified 1, 5-pentamethylene diisocyanate product, the product yield is 66%, and the content of hydrolytic chlorine is 45 ppm.

Example 4:

adding 4kg of methyl salicylate into a 20L glass reaction kettle, introducing gaseous phosgene, after phosgene is dissolved and saturated, uniformly mixing 1 kg of 1, 5-pentanediamine and 5 kg of methyl salicylate, adding the solution into the glass reaction kettle by using a metering pump at the flow rate of 30 mL/min, continuously introducing the gaseous phosgene, controlling the reaction temperature to be 10-20 ℃, and continuously reacting for 0.5 h after the dropwise addition is finished, thereby finishing the cold-luminescence reaction. Then raising the reaction temperature to 70-100 ℃ for 1 h, and continuing raising the temperature to 160-200 ℃ for reaction until the photochemical solution is clear and transparent, and finishing the reaction. Phosgene removal, solvent removal and product refining are carried out on the photochemical solution to obtain a qualified 1, 5-pentamethylene diisocyanate product, the yield of the PDI product is 77%, and the content of hydrolytic chlorine is 49 ppm.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included therein.