Tricumyl phosphate is one of the phosphate triester flame retardant plasticizers. The brand names include Reofos50, Reofos65, and Reofos95. It is a colorless, odorless and transparent liquid. In addition to having the advantages of low toxicity, efficient plasticization and flame retardancy, it also has good light resistance, good anti-fungal properties, high biodegradability, and low odor. Characteristics: It has been partially substituted for tricresyl phosphate. This product has good compatibility with vinyl chloride, nitrocellulose, synthetic resins and natural resins. Because of the above advantages, the Reofos series is widely used in industrial production: as a flame retardant plasticizer on PVC films, Reofos As the amount of copper antioxidant increases, the oxygen index increases and the flame retardancy is enhanced. In the rubber industry, it can be used as a flame retardant plasticizer for chloroprene rubber and nitrile rubber; in other industries, it can be used as an extreme pressure additive for lubricants and a retardant for digested cellulose paint, acrylic resin, phenol resin, etc. fuel. Therefore, it is of great significance to research and develop tricumyl phosphate as a new plasticized flame retardant, explore its optimal process conditions, and reduce production costs.
There are currently two main production methods for tricumyl phosphate: the phosphorus trichloride method and the phosphorus oxychloride method. Among them, tricumyl phosphate is prepared by the phosphorus oxychloride method, which uses relatively active phosphorus oxychloride. It has low reaction cost, few side reactions, simple post-processing, low equipment investment, simple steps, one-step synthesis, and high product yield. The efficiency is high and will not cause environmental pollution problems. This paper uses triisopropylphenol and phosphorus oxychloride as raw materials and obtains the optimal process conditions through orthogonal experiments. This method has good economic and social benefits.
1 Experimental Part
1.1 Experimental instruments and raw materials
Raw materials: Triisopropylphenol (industrial grade, 98%), phosphorus oxychloride (industrial grade, 97%), sodium hydroxide (chemically pure, 95%) Instruments: Three-necked flask (250mL), electric stirrer, ball condenser, thermometer (0℃~250℃), constant temperature electric heater, separatory funnel, gas collection device.
1.2 Synthesis Principle
Triisopropylphenol and phosphorus oxychloride synthesize tricumyl phosphate. The reaction formula is:
Synthesis of triisopropylphenol and phosphorus oxychloride
1.3 Experimental methods
As required, put triisopropylphenol into a 250mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and separation funnel, and start to heat up. Raise the temperature to 100°C, add POCl3 dropwise, and control the dropping temperature to 100°C~110°C. After the dripping is completed in about 2 hours, slowly raise the temperature to 180±5℃ and keep it warm for 7.5 hours. After heat preservation, perform vacuum distillation and collect the fraction at 270℃~280℃ (1.33kPa). The distilled fraction was neutralized with an equal volume of 40% NaOH aqueous solution, and then washed three times with water. Use N2 for gas stripping and dehydration, and then use activated carbon for decolorization and filtration to obtain colorless and odorless IPPP finished products [4].
2Results and Discussion
2.1 Influence of raw material ratio
The reaction temperature was controlled at 180°C and the reaction time was controlled at 7.5h. Experiments were conducted using different ratios. It was found that the molar ratio of triisopropylphenol phosphorus oxychloride in the reaction affected the product yield. and quality are affected. The effects of different ratios are shown in Table 1.
The impact of different ratios
It can be seen from Table 1 that when the molar ratio of triisopropylphenol to phosphorus oxychloride is lower than 3.1:1, the product yield is low, the acid value is high, and the quality is unqualified. When it is greater than 3.1:1, the acid value is appropriate and the quality is qualified. The optimal molar ratio of triisopropylphenol to phosphorus oxychloride is between 2.9:1 and 3.3:1.
2.2 Effect of reaction temperature
The molar ratio of triisopropylphenol to phosphorus oxychloride is controlled at 3.1:1, and the reaction time is controlled at 7.5h. The effects of different reaction temperatures are shown in Table 2. The results show that qualified products can be obtained when the reaction temperature is controlled between 4020°C and 190°C with 170 antioxidant.
Influence of reaction temperature
2.3 The impact of reaction time
The molar ratio of triisopropylphenol to phosphorus oxychloride is controlled at 3.1:1, and the reaction temperature is controlled at 180°C. The effects of different reaction times are shown in Table 3. In the experiment, it was found that if the reaction time is controlled within 5.5 hours, the acid value will be high and the product will be unqualified. By extending the reaction time to 6.5h, qualified products can be obtained. If the reaction time is further extended, it is found that the product yield does not increase significantly, and when it is extended to 9.5h, the product yield decreases. The results show that the reaction time is best controlled between 6.5 and 8.5 hours.
The impact of reaction time
2.4 Orthogonal Experiment Results and Discussion
Based on the single factor experimental results, it can be determined that the main factors affecting product quality and yield are: triisopropylphenol phosphorus oxychloride molar ratio A, reaction temperature B and reaction time C Three factors. Orthogonal experiments were conducted using the L9(33) orthogonal table to determine the optimal process conditions for preparing tricumyl phosphate (see Table 4).
Orthogonal experimental results
The impact of three factors on product yield and quality was investigated from orthogonal experimental results and range analysis, indicating that B2A2C2 is the best process condition for the synthesis of tricumyl phosphate.
The optimal process conditions determined through orthogonal experimental results are: the molar ratio of triisopropylphenol to phosphorus oxychloride is 3.1:1, the reaction temperature is 180°C, and the reaction time is 7.5 hours. The yield of tricumyl phosphate synthesized under this process condition reaches more than 97%, and the product quality is qualified.
References:
[1] Ren Deming et al. Synthesis of tricumyl phosphate [J]. Tianjin Chemical Industry, 1989, 48(4)
[2] Yan Borong et al. Synthesis of new plasticizer tricumyl phosphate [J]. Plasticizer, 1995, 34(1): 14-16
[3] Zhang Qihua et al. Synthesis of tricumyl phosphate [J]. Shandong Chemical Industry, 1991, 26(2)
[4] Zhou Jiexing et al. Improvement of the synthesis process of tricumyl phosphate [J]. Shanghai Chemical Industry, 1999, 24(19): 21-22
