Synthesis and Application of New Flame Retardant BDP
What is acetic acid and what are its effects
21 11 月, 2020vinyl neodecanoate CAS 51000-52-3
11 1 月, 2021Synthesis and Application of New Flame Retardant BDP
一、Product overview:
Bisphenol-A bis(diphenyl phosphate) CAS 5945-33-5
Currently, flame retardants for engineering plastics are mainly halogen flame retardants, which are restricted due to their pollution and toxicity during production and use. Phosphorus flame retardant, as an environmentally friendly flame retardant, has the characteristics of smokeless and low toxicity. The European Union and other developed countries have banned the use of halogen-based flame retardants in the future, and relevant Chinese regulations are also being formulated. However, there are few types of phosphorus-based flame retardants for engineering plastics in the Chinese market, and the varieties are slightly poor. We need to strengthen research and development. Bring new flame retardants.
Flame Retardant-Bisphenol A-Bis (Diphenyl Phosphate) or BDP is an environmentally friendly non-halogen organophosphorus flame retardant, suitable for thermoplastic materials, especially for the flame retardant modification of PC/ABS blends It is easy to reach the UL-94V-0 standard, which can increase the impact resistance of plastics and the resistance to degradation in humid environments.
Advantages: non-halogen, high phosphorus content, high molecular weight, low volatility, flame retardant plasticization, etc.
二、Experiment
1、Selection of synthesis method
At present, there are three main synthetic processes for BPD:
(1) Phosphorus oxychloride reacts with bisphenol A to obtain bisphenol A tetrachlorobisphosphate, which is then capped with phenol to obtain the target;
(2) Phosphorus oxychloride reacts with phenol to obtain diphenylphosphoryl chloride, and then reacts with bisphenol A to obtain the target product;
(3) Use sodium phenolate instead of phenol as raw material, that is, use sodium phenate to end-capping bisphenol A tetrachlorobisphosphate to obtain the product.
In this experiment, a method with relatively simple operation and readily available raw materials was used (1) Synthesis of BDP, using phosphorus oxychloride, bisphenol A, and phenol
As a raw material, it is synthesized by a two-step catalytic reaction synthesis method, the reaction is as follows:
first step
Second step
2.Drugs and laboratory equipment needed for the experiment
Medicines: Phosphorus oxychloride (CP), bisphenol A (CP), phenol (AR), anhydrous magnesium chloride (AR), aluminum trichloride (AR), anhydrous calcium chloride (AR), hydrochloric acid (AR) , Toluene (AR), propylene oxide (CP), sodium hydroxide (AR), 0.2% phenolphthalein reagent.
Instruments: Nikon SX170 FTIR spectrometer KDM type temperature control electric heating jacket, SHZ-D (III) circulating water vacuum pump, NDJ-1A rotary viscometer, electronic balance.
3.Synthesis steps
first step
Add catalyst and phosphorus oxychloride to the flask in turn, heat and turn on the electric stirrer. The temperature was increased and bisphenol A was added, and nitrogen was introduced during the reaction. The temperature is slowly raised to 100°, the reaction temperature is controlled at 100-110°, and the reaction is carried out for 5 hours. When the amount of HC1 generated is small (use PH test paper to detect), stop heating.
When the temperature of the reactant is below 80°, use a vacuum distillation device to distill excess phosphorus oxychloride. The product is an intermediate-tetrachlorobisphosphate-bisphenol A, a light yellow viscous transparent liquid.
Second step
The intermediate product is heated to 120°, phenol is added, and nitrogen gas is introduced during the reaction. Control the temperature within the range of 140-160°, and let the reaction proceed for 6 hours, until the amount of HC1 produced is small (tested with PH test paper), stop heating.
When the temperature of the reactants is below 80°, use a vacuum distillation device to distill excess phenol. The product is crude BDP. Light yellow viscous liquid.
Crude product handling
Add toluene and propylene oxide of the same quality to the crude product, heat and stir to mix evenly. Pickled with 1% hydrochloric acid at 75° for 15 minutes, set aside for layering, and discard the supernatant. The lower oily substance was washed three times with tap water at 75° for 15 minutes each time.
The lower oil layer is distilled with a vacuum distillation device for about 2 hours to obtain the product BDP, which is a pale yellow viscous liquid.
三、Results and discussion
The synthesis of BDP is affected by many factors. In this paper, a single-factor experiment method is used to investigate the catalyst and reaction temperature;
The orthogonal experiment method was used to discuss the influence of the feed ratio, the amount of catalyst, and the reaction time on the yield of the target product, and the appropriate reaction conditions for the synthesis of BDP were determined.
1.Selection of catalyst
Magnesium chloride, aluminum chloride and calcium chloride are suitable catalysts mentioned many times in this article, so the most ideal catalyst was selected from these three substances. The catalyst was investigated under the condition that the feeding ratio, reaction temperature and catalyst dosage (0.8% of the bisphenol A feeding amount) remained unchanged. The experimental results are shown in Table 1-1
2. The first step is to determine the reaction temperature
If the reaction temperature in the first step is too low (below 75°), the reaction will proceed very slowly and the reaction will be insufficient; if the temperature exceeds 125°, the color of the product will become darker, the by-products will increase, and the yield of the target product will be reduce. The relevant experimental results are shown in Table 1-2
2.Determination of the reaction temperature in the third step
3、In the third step of the reaction process, add phenol at an appropriate temperature to convert the intermediate product generated in the first step into the final target product. If the reaction temperature is too low, the reaction process will be too slow, if the reaction temperature is too high, it will Increased side reactions, see 1-3 for the relevant experimental results
4. Orthogonal design experiment
The feed ratio (bisphenol A: phosphorus oxychloride: phenol, molar ratio), the amount of catalyst (BPA, wt%) and the reaction time are operated by orthogonal design. Table 1-4 is a table of factor levels in this experiment, and Table 1-5 is Lg(3^4)
Through orthogonal experiment analysis, the following conclusions are obtained:
(1) Feeding ratio: 1:2.5:4.2 (BPA:POCL3:PhOH)
(2) The amount of catalyst: 0.8% wt of BPA
(3) The first step reaction time: 5.5h
(4) The second step reaction time: 6.5h
5. Analysis and discussion of crude product handling
Through comparative analysis, the addition of chelating agent (1% hydrochloric acid) and the catalyst metal ion form a water-soluble chelate, and the catalyst ion is removed by water washing; the addition of propylene oxide reacts with by-products to form an aqueous substance, which is washed by water Method to remove. Because of the high viscosity of the crude product, it is diluted with toluene of equal quality first. Generally 3 times of water washing is advisable, 15 minutes each time (75°). If the number of washing times is too much, it will be difficult to separate the oil phase and the water phase.
6. Scale-up experiment
A scale-up experiment was done on the basis of the successful experiment and the optimization of the synthesis conditions. The synthesis steps and the processing process of the crude product are the same as 2.3. The feeding conditions are shown in 1-6, and the yield, viscosity and acid value are shown in 1-7.
