Studies On Preparation Of SiO₂-PVDF Bipolar Membrane And Pilot Production Of Succinic Acid And P-Chlorobenzaldehyde Using Paired Electrosynthesis Technology

In this paper,SiO₂-PVDF cation and anion exchange membrane were prepared,respectively.And the optimal preparation conditions were determined,which were as follows:the ratio of poly?vinylidene fluoride??PVDF?to the mixture mass of glycidyl methacrylate?GMA?and divinyl benzene?DVB?was 2:1,and for the cation and anion exchange membrane,the amount of crosslinking agent DVB was respectively 4%and 5%of GMA and the addition amount of SiO₂ was respectively 0.10%and 0.15%of the total weight.Then the SiO₂-PVDF cation and anion exchange membrane were used to prepare bipolar membrane?BPM?by hot-pressing approach.The cross-section of the BPM was observed using scanning electron microscopy?SEM?.SEM image indicated that the cation and anion membrabe layer were combined were closely combined with each other.There was no bubble and gap in the interlayer.The optimal hot-pressing temperature was 190? and optimal hot-pressing pressure was 10 Mpa.Furthermore,the cell voltage-current density curve of the prepared BPM was investigated.The carboxymethyl cellulose?CMC?-polyvinyl alcohol?PVA?/chitosan?CS?-PVA bipolar membrane was modified by nano silicon dioxide.Then the prepared BPM was used as electrolysis cell septum to electro-generate p-chlorobenzaldehyde and succinic acid by electro-catalytic process,respectively.And then the optimal conditions to paired electro-generate p-chlorobenzaldehyde and succinic acid were determined,which were as following:electrolysis current density was 45 mA/cm²,the interelectrode distance was 2 cm,reaction tem-perature was 60 ?,the ratio of p-chlorotoluene to Mn3+ was 4:1 and the concentration of sulfuric acid was 7.0 mol/L in the anode chamber,and the sulfuric acid concentration was 1.0 mol/L and the initial concentration of maleic anhydride was 1.0 mol/L in the cathode chamber.Moreover,the process flow and the electrolysis cell units were designed.According to the designed process flow and paired electro-generation conditions,the material balance and corresponding economic evaluation of the succinic acid and p-chlorobenzaldehyde production were studied.The economic benefits for succinic acid and p-chlorobenzaldehyde production were about 11030 yuan per ton and about 22300 yuan per ton,respectively.Therefore,the paired electro-generation technology of succinic acid and p-chlorobenzaldehyde using bipolar membrane has a good application prospect.