What Triethyl phosphate (flame TEP) process is

Triethyl phosphate (flame TEP) is widely used [1], can be used for catalysts, solvents, stabilizers, synthetic resins, pesticides, lubricant additives, but also for the plant growth regulator, a defoaming agent, cellulose acetate dyeing auxiliaries, fluorescent glass paint production. Current domestic production of Triethyl phosphate (flame retardant TEP) has the following methods: (1) the use of added hydrogen or hydrogen chloride to form a solid amine hydrochloride salt [2] Preparation of Triethyl phosphate; (2) by ethanol, sodium acetate and phosphorus trichloride obtained [3]; (3) in POCl3 phosphorus acidifying with fatty alcohols, polyoxyethylene alkyl phenol ether or an esterification reaction, which is industrially synthesized phosphate An important method [4]. Trialkyl phosphite domestic production process common problem is low yield of only 45% to 50%, such as methyl triphosphate, triethyl ~ 50% 60% 65% Tributyl [5]. Based on the reaction mechanism triethylphosphate (flame TEP), using orthogonal test material ratio, reaction temperature, reaction conditions were optimized to obtain a 82% yield.

1 Experiment
1.1 Reaction Mechanism
Main reaction:
POCl3 +3 C2H5OH (C2H5O) 3PO +3 HCl
The actual reaction in three steps:
POCl3 + C2H5OH (C2H5O) POCl2 + HCl (1)
(C2H5O) POCl2 + C2H5OH (C2H5O) 2POCl + HCl (2)
(C2H5O) 2POCl + C2H5OH (C2H5O) 3PO + HCl (3)
Side effects:
(C2H5O) 3PO + HCl (C2H5O) 2PO • OH + C2H5Cl
C2H5OH + HCl C2H5Cl + H2O
(C2H5O) 3PO + H2O (C2H5O) 2PO • OH + C2H5OH main reactor 1, step 2 reaction (esterification 1) faster,
Step 3 reaction (esterification 2) slow control response.
1.2 Experimental Procedure
To 100mL (1.07 mol) of phosphorus oxychloride with a stirrer into 250mL four-necked flask, cooled with ice-salt to less than 15
℃, then added dropwise 92 mL (1.60 mol) of ethanol in vacuo. In another 1000mL four-necked flask with a stirrer, into 550mL (9.63mol) in ethanol, a solution of the above product under pressure, cooled with ice-salt, to ensure the reaction temperature is less than 15 ℃. The reaction mixture was vacuum-0.098MPa high ethanol recovery. Control the distillation temperature is less than 55 ℃, the ethanol recovered in the two applied to the esterification, and then the remaining product was neutralized with caustic to a pH of 6-7, and extracted, and then distilled to obtain the finished 165.05 g. 2 Results and discussion
2.1 esterification reaction condition selection
Depending on the reaction mechanism, an esterification reaction speed, a large amount of hydrogen chloride; 2 esterification reaction is slow and hydrogen chloride are produced slower speed. Thus a controlled amount of ethanol esterification stage, using phosphorus oxychloride was added dropwise to ethanol manner that the relative excess of phosphorus oxychloride in the state, the basic guarantee to the reaction product between an acrylate ester, while the use of vacuum suction way to remove the hydrogen chloride; esterification stage 2 atmospheric pressure while adding excess ethanol esterification reaction tends to ensure complete. Primary esterification step esterification processes, the drawback is not very well remove hydrogen chloride, hydrogen chloride generated per unit time in the more easy to produce by-product, and the product easy to acid hydrolysis. The reaction mode may be used to effectively avoid the situation.
Esterified in a more stringent control of vacuum, high vacuum material oxychloride away easily, so that the vacuum is too low hydrogen accumulation, the vacuum should be determined according to the size of the hydrogen chloride generated in the reaction rate. Vacuum control in this experiment -0.06 ~-0.098MPa. Esterification 2 must be considerably in excess of ethanol, complete esterification, and the excess alcohol may be dissolved hydrogen chloride, hydrogen chloride in ethanol was recovered out, neutralized with a base to reduce the amount of water to reduce the generation of suppressing side reactions. Also this reaction is an exothermic reaction, thus reducing the temperature of the esterification reaction to facilitate the reaction in the positive direction. These are triethylphosphate (flame TEP) process, such as Triethyl phosphate (fire retardant TEP) Want to learn other aspects of the product, please click on the link behind the link, triethylphosphate tep standard quality single COA. For more information, please visit the official website of Zhangjiagang Chemical Co. Yarui: http://www.yaruichem.com