A Experimental Study On The Synthesis Of Sodium Ethoxide With Vapor Permeation Membrane Reactor

Sodium ethoxide is commonly used in industrial intermediates and catalyst. In traditional industries, the main production method of ethanol sodium is azeotropic-reactive distillation, which has advantages of high yield, high purity, but also facing the energy consumption, water consumption, pollution of the environment and other issues.Vapor permeation membrane separation technology is a new technology, which is advantaged in such as distillation azeotrope, near azeotrope and other systems that distillation can not, particularly suited for the separation of traces of water. On the other hand, Vapor permeation has no phase change in permeation process, so it can lower energy consumption.Vapor permeation membrane reactor is a new reaction-separation technology in recent years, which the reaction and separation coupled together to achieve in situ separation. It can increase the reaction rate, shorten the reaction time, and lower environmental pollution, lower energy consumption.But at the same time, vapor permeation also faces the problem of vapor-liquid equilibrium. For various reasons, the system does not reach the vapor-liquid equilibrium in the pervaporation process, which resulted in the target component in the front side of membrane and driving force through the membrane are reduced, greatly reducing the permeation flux and separation factor, so that vapor permeation lowers its advantages. Thus, the role that enhanced vapor-liquid mass transfer in the process of vapor permeation is an important issue on vapor permeation membrane reactor.This thesis prepared high separation factor of PVA/PES composite membrane successfully, and determined the PVA/PES composite membrane preparation conditions. The effects of cyclohexane, feed temperature, liquid water content of ethanol-water binary system on vapor-liquid composition, and the effects of cyclohexane, feed temperature, liquid water content of ethanol-water separation performance on VP are investigated. At the same time, it will also be applied to the vapor permeable membrane reactor made experimental studies of sodium ethoxide, and the effects of amount of cyclohexane added, temperature, NaOH concentration on the process are also investigated.Experimental results show that PVA concentration of5wt%of PVA/PES composite membrane has better performance which has a high separation factor and flux, and less loss of cyclohexane. Cyclohexane can affect ethanol-water vapor-liquid composition, and can play a strengthened role of the vapor-liquid mass transfer and improve the water content of the vapor phase, thereby increase the permeation flux and separation factor. As the temperature rises, the water content of the vapor phase gradually increases, but the strengthening effect of cyclohexane is gradually decreased; as the added amount of cyclohexane increases, strengthen the role of cyclohexane first increased and then decreased. At the same time the water content of the feed solution will also affect the strengthening effect of cyclohexane, but also determines the optimum amount of cyclohexane added.In the experiment of preparation of sodium ethoxide with VPMR, the amount of cyclohexane is2wt%is better. The higher feed temperature, the rate of water removal is greater; the time required for complete reaction is shorter. Meanwhile, the higher the concentration of sodium hydroxide, the slower conversion rate increasing trend, the longer the time required.