A Study On Synthesis And Properties Of Asymmetric Fumarate

Fumarate is a kind of low-toxicity preservatives with broad-spectrum and high-efficiency sterilization ability that has been developed and applied in recent years.With the deepening of research and wide application,it was discovered that the earliest developed and applied dimethyl fumarate has the disadvantage of a strong stimulating effect on human skin and mucous membranes,and the use of dimethyl fumarate was restricted.Therefore,the research and development of new fumarate has important theoretical and application values.Studies have shown that the?,?-unsaturated carbonyl structure in the fumarate molecule has a bactericidal effect;compared with dimethyl fumarate,the monoalkyl fumarate has almost no odor and has good antibacterial properties,but simple fumaric acid monoester compounds can dissociate under certain conditions,and the form with the best antibacterial effect is non-ionic state.In this study,while retaining the?,?-unsaturated carbonyl structure in the fumarate molecule,the hydrophobic tail chain in the fumarate molecule was changed in order to obtain new compounds that can avoid or mitigate the disadvantages of dimethyl fumarate and have good anti-mold properties,and to explore the use of the synthesized new fumarates as plasticizing modifiers for plastics,and studied the plasticizing and antibacterial properties.In this study,three types of fumaric acid monoesters and five types of fumaric acid diesters were synthesized by the traditional esterification method and the new type of transesterification method.In the experiment,maleic anhydride was used as the starting material.Firstly,it was esterified with n-butanol,n-octanol,and isooctyl alcohol to prepare the corresponding maleic acid monoester,and then the maleic acid monoesters were isomerized to fumaric acid monoesters in the presence of catalyst;Secondly,monobutyl fumarate,mono-n-octyl fumarate,and mono-iso-octyl fumarate were esterified with methanol to obtain methyl butyl fumarate,methyl-n-octyl fumarate,methyl isooctyl fumarate and other methyl asymmetric fumarates;Finally,mono-n-octyl fumarate and mono-iso-octyl fumarate were esterified with n-butanol to obtain butyl-n-octyl fumarate and butyl-iso-octyl fumarate.Using dimethyl fumarate as raw material,through transesterification with n-butanol,n-octanol,and isooctyl alcohol,methyl butyl fumarate,methyl n-octyl fumarate,methyl isooctyl fumarate are prepared.The effects of factors such as the type and amount of catalyst,the ratio of raw materials,the reaction temperature,and the reaction time on the yield of fumaric acid monoester,methyl fumarate,and butyl n-(iso)octyl fumarate have been experimentally studied.The optimized reaction conditions were determined.The experiments show that the transesterification method has the advantages of simple process and convenient operation.IR,~1H-NMR,MS and other characterization methods were used to analyze and characterize the structure of the reaction product;using a micro melting point instrument(freezing point tester),the melting point or freezing point of the synthesized asymmetric fumaric acid monoester and asymmetric fumaric acid diester were measured.At room temperature,asymmetric isooctyl fumarate is liquid,has good low temperature fluidity and is easy to use.Experiments have been conducted to study the inhibitory effects of the 8 asymmetric fumarates synthesized on Escherichia coli and Staphylococcus aureus and their plasticizing and antibacterial properties on plastics.The minimum inhibitory concentration and inhibitory rate of the synthesized asymmetric fumarate against Escherichia coli and Staphylococcus aureus were determined by the plate coating counting method and the turbidimetric method.The experiment showed that the synthesized asymmetric fumarates have good antibacterial effect;The plate coating method was used to measure the diameter of the inhibition zone of asymmetric fumarate-modified polyvinyl alcohol(PVA)film.The results show that the PVA film modified with asymmetric fumarates have obvious bacterial effect,and the antibacterial effect will increase with the increase of the amount of additives.Through TG,DSC and other analytical methods,the structure and thermal properties of the modified PVA film were characterized.The melting point and crystallinity of the PVA film added with asymmetric fumarate decreased,which improved the plasticity of the PVA film and its heat resistance.Therefore,the PVA film added with asymmetric fumarate has obvious antibacterial,preservative and plasticizing properties,and can be used to prepare a food antibacterial packaging material.The plate coating counting method and the turbidimetric method were used to measure the minimum inhibitory concentration and inhitory rate of the synthesized asymmetric fumarate against Eschevichia coli and Staphylococcus aureus.