Study On Preparation Of Benzene Phosphorus Thiodichloride And Its Promotion By Ultrasound

Benzene phosphorus thiodichloride(BPT) is an important intermediate product inorganic synthesis. It can be used in preparation of pesticide, organophosphorousfire-proofing agents, oil additives, extreme pressure lubricants, and antioxidants. Ithas been widely used and has capacious market.In this work, by the way of integrative method, benzene phosphorusthiodichloride has been synthesized with benzene and phosphorus trichloride as basicmaterial under low temperature and normal pressure. The process was improved andoptimized by studying different factors.The optimal reaction conditions (n(PCl3) : n(C6H6) : n(AlCl3) :n(S) =3.0:1.0:1.1:1.0, and5 hours reflux reaction) were obtained by orthogonal design under different conditions.Its yield comes up to 78.5%, which is 5% higher than that were reported in literatures.Parallel experiments also had good results, which verified the reliability of thissynthesis process. The product was identified by physical characters, GASchromatogram, infrared chromatogram, MS analysis. The spectrum of the productcoincides with the standard spectrum of BPT.Because there are two main reactions in the BPT synthesis, so used ultrasoundduring each of them independently, to study the influences of ultrasound on the BPTyield.Ultrasound was used during the first synthesis reaction, i.e. reflux reaction, inBPT synthesis process. The reaction rate under ultrasound irradiation is far higherthan that of normal reaction. Without ultrasound, it needs 300min for the refluxreaction to get a yield of 78%, but with ultrasound irradiation during the refluxreacting, it needs only 80min for the reflux reaction to get the same yield. Ultrasoundfrequency, sound pressure and sound treatment time are also important factors for theBPT yield in the ultrasonic synthesis. At the beginning of the reaction, the reactionrate with high ultrasound frequency was fast than that with low ultrasound frequency.But with the passage of time, low frequency is better than high ultrasound frequency.Higher sound pressure has advantage for the reaction rate than low sound pressure. IIIContrast with normal synthesis, ultrasonic synthesis cannot get more products. Theultrasonic synthesis reaction does not change the mechanism of the synthesis reaction.Ultrasound only intensifies mass transfer of the process.Ultrasound was also used during the experiment of second synthesis reaction, i.e.sulfurization, in BPT synthesis process. Without ultrasound, it needs 60min for thesulfurization reaction to get a yield of 78%, but with ultrasound irradiation during thesulfurization reacting, it needs only 25min for the sulfurization reaction to get thesame yield. The research result about an influence of ultrasound is the same as theresult of the experiment in first synthesis reaction.Wastewater that was produced during the BPT synthesis was analyzed, and atreatment method was given.