Paired Electrosynthesis Benzaldehyde And Hexanehexol

Benzaldehyde is an important industry material of medicine,dye,perfume and resin,it also be used as solvent,plasticser and low temperature lubricant, and so on. It is used for edible essence,less for daily and tobacco use.Benzaldehyde is an important intermediate for manufacture perfume,spice and aniline dyes.Tranditional method has the problem in environmental contamination,low yield and poor purity,so electrochemical synthesis benzaldehyde gts a lot of attention in recently years.Sorbitol and Mannitol are belong to hexanehexol.Sorbitol was widely used in food,daily chemicals and medicine industry.It’s a main material for producing vitamin C and used for sweetener,moisturizer,excipient and preservative.At the same time,it has nutritional merits of polylols,such as low calorific value,low candy and anticarious function.Mannitol is the material for production nitroglycerin.Could be used as diuretics,decrease intracranial pressure and intraocular pressure,kidney medicine,dehydration,sugar substitutions and also be used for pill excipient,solids and liquds thinner,hangover drug and freshener for chewable. The methods of producing Sorbitol include catalytic hydrogenation,electrochemical and bio-fermentation, seaweed abstraction is the main method for manufacture Mannitol,from the waste water after extraction Iodide and Sodium alginate.Besides, it can be production by catalytic hydrogenation,electrochemical and bio-fermentation.Because electrochemical method with mild reaction condition,convenient operation and no environment pollution is a new type and eco-friendly synthesis method.Electrochemcal synthesis Sorbitol and Mannitol was studied by more and more people.This article intends to set up a new paired electrosynthesis systerm for preparation Benzaldehyde,Mannitol and Sorbitol simultaneously.First,this paper used foam nickel as the substrate prepared NiOOH on the electrode surface by constant-current electrolysis.From the CV test indicated that the NiOOH has the better catalytic activity than foam nickel,the NiOOH ganeration at electrode surface is controled by surface diffusion.The reaction of benzyl alcohol at electrode surface accord with EC mechanism,ganeration NiOOH at electrode surface first,then the NiOOH oxidize benzyl alcohol to benzaldehyde.In an undivided electrolytic cell,use NiOOH as anode,Ni as cathode, preparation of benzaldehyde from benzyl alcohol oxidization.The factors influencing the current efficiency of synthesisi benzaldehyde such as reaction temperature, electrolysis current,alkali dosage and organic solvents, were investigated,and optimized by orthogonal experiments.All the experiment data indicated the current efficiency of benzaldehyde is not high,the best efficiency is 50.81%.adding organic solvents is the ultimate effect of this experiment, especially adding methanol that significantly reduced current efficiency This is mainly due to methanol was oxidated.The effect of adding acetonitrile and THF is not obvious than without organic solvent,and that take the new problem to separate and deal with products when adding organic solvents.So use organic solvents for adding benzyl alcohol solubility is not adopt in latter experimentIn divided cell,NiOOH as anode,Pb as cathode,NaOH as electrolyte preparation benzaldehyde from selective oxidation benzyl alcohol at NiOOH electrode,the results show NiOOH has good selectivity and catalytic activity.The effect of electrolysis current,reaction temperature, alkali dosag and addition of benzyl alcoholon the current efficiency was investigated. The optimum conditions of synthesis have been achieved by orthogonal design: temperature is 25℃,electrolysis current is 0.5A, alkali is 0.7g, the five times theoretical amount benzyl alcohol,The efficiency reached to 97.23% at the optimal experimental conditions.That lay the foundation of paird electrosynthesis in letter work.Based on previous test,investigated preparation benzaldehyde by oxidation benzyl alcohol on anode,while the possibility of get hexanehexol from glucose.In paired electrosynthesis,keep the anode alkali and alcohol addition unchanged,search optimal conditions for total current efficiency by changing electrolysis current,alkali and glucose dosage at cathode.investigated the influence of previous factor on cathode and total current efficiency by orthogonal design.The results show that total efficiency can reached 180.85% the optimum conditions by rthogonal design:current is 0.1A,cathode alkali is 0.1g and the 3 times theoretical amount glucose.