Study On The Preparation Of [2,2]-Paracyclophane Derivatives

Parylene film is a kind of polymer material,which is prepared by vacuum fine forging technology of parycyclophane and its derivatives.The applications of Parylene film have been widely developed in biocompatibility,aerospace,micro-electronic machinery?MEMS?,cultural relics protection and other fields because of its excellent properties such as air impereability,mechanical properties,electrical properties and transparent film with chemical inertia.The synthesis process of Parylene thin film precursors were investigated,optimized,and enlarged presently,which resulted in an enhanced product yields.Finally,the developed processes were expected for industrialization.Firstly,the synthesis process of 4-aminoparycyclophane?Parylene A precursor?was studied.The synthesis of the Parylene A precursor was generally divided into two steps,4-nitro parycyclophane was firstly synthesized from parycyclophane and nitric acid/sulphuric acid/glacial acetic acid system through nitration reaction followed by further recrystallization step.Then,4-aminoparycyclophane was obtained from hydrogenation of 4-nitroparycyclophane over metal catalyst.In the nitration step,the effects of nitration systems,solvents,reaction times,recrystallization conditions on the product yield were investigated.In the hydrogenation step,the catalyst types,solvents,temperature,pressure of H₂ on the product yield were investigated.The maximum yield of 4-nitroparycyclophane was obtained under the optimum conditions of n?N?:n?HNO₃?=1:1.29,n?N?:n?H₂SO₄?=1:2.4,in dichloromethane solvent at 5-6min reaction time.The maximum yield of 4-aminoparycyclophane was obtained under the optimum conditions of 60 ^oC,3 MPa H₂,with Pd/C catalyst in THF at 3.5 h reaction time.Then,after the process optimization,the stability test was carried out on the results of the pilot test,and 42.2-45.6%product yield was obtained with purity of99.5%.Secondly,the synthesis process of 4-formyl parycyclophane,the precursor of Parylene H,was studied.The synthesis of Parylene H precursor is based on the reaction of parycyclophane with dichloromethylether using titanium tetrachloride as Lewis acid catalyst.The effects of catalyst types,co-catalyst,molar ratio of reactants and reaction time on product yield were investigated.The optimum technological conditions were obtained under the optimum conditions of using titanium tetrachloride as catalyst,nitromethane as co-catalyst,n?parycyclophane?:n?TiCl₄?=1:1.6,n?parycyclophane?:n?CH₃OCHCl₂?=1:1.2,reaction time at 2.5 h.After recrystallization,76.5%product yield with purity of 99.5%was obtained.In addition,the reaction process was simulated by Gauss algorithm,and the reaction mechanism was explored.Finally,the synthesis process of 4-methylamino parycyclophane,a precursor of Parylene AM,was studied.In this reaction,4-formyl parycyclophane was synthesized from raw material given in the previous chapter,which is fed into ammonia and hydrogen.The raw material firstly reacted with ammonia to form an enamine,and then reacted with hydrogen to produce a product.The effects of catalyst types,reaction temperature,reaction pressure and reaction time on the yield of the product were investigated.The optimum process conditions were obtained under the optimum conditions of using Raney nickel as catalyst,reaction temperature on 60?,hydrogen pressure of 3 MPa and reaction time at 5 h.The yield of the product could reach90.2%,and the purity of the product could reach 99.1%.