Investigation Of The Catalytic Properties Of Rubidium Phosphate On Transfer Hydrogenation And Transesterification

The storage of rubidium in the earth's crust is huge. And most of them spread in salt lake brine, seawater and geothermal water. Due to the underdevelopment of the separation and processing technology of rubidium and the backward of the production technology of rubidium compounds, rubidium and its compounds are seldom used in industry. In recent years, more and more rubidium separation technol ogies have been reported, thus greatly promoted the application of rubidium and its compounds.By slowly dropping the nitric acid solution of potassium pyrophosphate into ammonium molybdate solution, large particle AMP is prepared. Through ammonium phosphate and titanium dioxide react under high temperature titanium pyrophosphate was prepared. After drying combinate titanium pyrophosphate with large particle ammonium molybdophosphate, obtained the large particle ammonium molybdophosphate-titanium pyrophosphate complex. Large particle ammonium molybdophosphate-titanium pyrophosphate complex was used in column adsorption of Saline Lake brine to obtain rubidium rich stripping liquid. After reextraction with t-BAMBP and baci-extraction with phosphate rubidium rich solution rubidium rich phosphate solution was obtained. Rubidium hydroxide was used to adjust the p H value, after that rubidium phosphate was obtained.This paper reported the high efficient transfer hydrogenation catalytic activity of Rb3PO4 for the first time, examined the catalytic performance of Rb3PO4 and K3PO4. Found that even after full water absorption Rb3PO4 has a higher transfer hydrogenation catalytic activity than dry K3PO4. Discussed how nitrogen protection affects transfer hydrogenation. The main reason of why Rb3PO4 has a higher catalytic activity than K3PO4 is that Rb atom has a higher adsorption capacity of aldehyde and ketone than K atom and the conductivity of Rb3PO4 is higher than K3PO4. All the substrates in this chapter can be reduction by Rb3PO4 under room temperature. The experiment results show that there are two different six-membered transition states for different aromatic substrates. When 4-bromobenzaldehyde or anisaldehyde is used as reactant pairs with benzaldehyde, the reaction rate of benzaldehyde is accelerated. Through experiment analysis a new six-membered transition state of M3PO4(M=K, Rb) catalyzed hydrogenation of aromatic aldehydes and ketones has been proposed. The six-membered transition state proposed can explain all the experiment results.Through investigation of the reaction kinetics of rubidium phosphate catalyzed transfer hydrogenation of 2,6-dichlorobenzaldehyde, we found that the reaction rate increase with the rising temperature. The control step of the whole reaction is the process of transfer hydrogenation. Achieve the reaction order. Ea and K 0 were obtained through calculating the Arrhenius equation. And the kinetic equation of rubidium phosphate catalyzed transfer hydrogenation of 2,6-dichlorobenzaldehyde was also obtained. This equation can well predict the reaction trend through test.This paper studied the transesterification catalytic activity of Rb3PO4. Found that Rb3PO4 could catalyze transesterification between Triacetin and methanol. the optimum reaction conditions were: molar ratio of alcohol and ester is 8:1, reaction temperature is 60°C, catalyst(Rb3PO4) dosage is 3wt%, reaction time is 2 hours. This paper laied the theoretical and practical basis for the catalytic application of Rb3PO4.