Preparation Of Organotex Tile Catalyst And Its Application In Phase Transfer Catalytic Reaction

Phase transfer catalysis is one of the effective ways to achieve high efficiency and low pollution of heterogeneous organic synthesis reaction.It is widely applied in the synthesis of fine chemicals such as dyes,auxiliaries and pharmaceutical intermediates.Most of the catalysts are soluble catalysts,which are toxic,expensive,and difficult to recycle.The solid phase transfer catalyst provides a solution to the above problems.The existing supported catalysts still had problems such as complicated separation process,poor reaction efficiency,and inability to achieve continuousization.Therefore,a new type of solid-supported catalyst that is cheap and readily available has become a difficult problem to be solved by phase transfer catalysis.In this paper,cotton and polyester fibers were used as carriers,and copolymer modifiers of five functional monomers were synthesized by solution polymerization.The modifiers are supported on the fibers by coating finishing to prepare a series of solid-phase transfer catalysts.Taking Williamson ether synthesis as an example,the activities of different supported catalysts were compared,and the effect of functional monomer structure on catalytic activity was discussed.A three-phase phase transfer catalytic reaction kinetic equation was established and the reaction mechanism was clarified.The main research contents of the paper are as follows:(1)Preparation of catalytic fibers.Five functional monomers:hydrophobic hard monomer,hydrophobic soft monomer,cross-linking monomer,solvent-resistant monomer and cationic monomer were used to synthesize the copolymer modifier,and the molecular structure of modifiers were characterized.The optimal finishing process of fabric was prepared,and the morphology and structure of organic catalyzed cotton-based fibers and the adsorption properties of oil-water two-phase were analyzed.The results show that the structure of the copolymer was correct,and the polymer began to crosslink when heated to 130?.The suitable conditions for the preparation of the catalytic fibers were two-impregnation and two-rolling,with a roll reduction of 90%,a baking temperature of 170?,a baking time of 1.5 h,and the amount of phosphoric acid of 12 wt%.After crosslinking,the copolymer had good stability and amphiphilicity.The three-phase air contact angle of water on its surface was close to 90°.The fibers after loading the copolymer still had a large specific surface area and a stable structure.The presence of nanostructures increased the contact angle of water from 90° to 135°;the presence of cations on the surface of the catalytic fiber allowed the fiber to still adsorb dyes in water,with a maximum adsorption capacity of 10%(m/m),and more lipophilic groups made it having better adsorption performance for organic solvents.(2)Study on the catalytic activity of catalytic fibers.The effects of different long-chain ester monomer structure,cationic monomer structure,polymer loading and molar amount of different cations on the catalytic activity of the prepared cotton-based and polyester-based catalytic fibers were analyzed.Etherification in other benzyl bromide derivatives and recyclability of organic catalyzed fibers were tested.The results show that with the increasing of the chain length of lipophilic monomers in the modifier,the contact angle of water on the surface of the catalytic fiber increased,and its catalytic activity and stability were improved.The effect of the accessibility of cationic monomers on the catalytic activity was greater than its lipophilic properties.The methacrylamide propyl dimethyl butyl ammonium bromide as cationic monomer,octadecyl methacrylate as hydrophobic long chain ester monomer,the molar content of the cation was 13.33%,and the organic catalytic fiber with a polymer loading of 20%had the highest catalytic activity and the most stable.When the organic catalytic fiber was reused 5 times,it can still ensure high catalytic activity and the structure of the fiber had no obvious change.The organic catalytic fiber showed good catalytic performance in the etherification reaction of other benzyl bromide derivatives.The highest reaction conversion rate was p-cresol,and the conversion rate reached 96%after 5 h reaction.(3)The liquid-solid-liquid three-phase catalytic reaction system was determined by a fitting method to determine a first-order reaction.Because the catalytic reaction interface was fixed,the cation concentration at the interface was limited,and the concentration of phenol anions in the water phase was excessive,the reaction rate was only related to the concentration of benzyl bromide in oil phase.The overall reaction was a first order reaction.During the catalytic reaction:catalytic central cation adsorbed p-cresol anion in aqueous phase,which the amphiphilic by quaternary ammonium salt cation and the lipophilicity of the hydrophobic segment structure of the polymer causes the supported fiber with the transitional active ion pair to enter the organic phase,and releases the nucleophilic p-cresol anion under micro-swelling conditions to make it reacted with the substrate pair.The catalytic center cation on the supported fiber was desorbed and then returned to the aqueous phase to adsorb p-cresol anion to form a cycle.