Study On Kinetics And Production Process Of Phenol Hydroxylation Based On TS-1 Monolithic Catalyst

Hydroquinone,as an important intermediate in industrial production,is widely used in rubber,dyes,medicine and other fields.In the tide of transformation and upgrading of chemical enterprises in China,the design of process with smooth operation,energy saving and environmental protection will be paid much attention.The hydroxylation of phenol with hydrogen peroxide is widely studied because of its simple and environmentally friendly process,energy saving.The difference of process lies in the types of catalysts.TS-1 molecular sieve has become an ideal choice for the phenol hydroxylation catalyst at present due to its excellent catalytic and thermal stability.However it is difficult to separate the powder catalyst from the product,and the recovery efficiency is low.Therefore,based on the TS-1/Cordierite Monolithic Catalyst,we design and simulate a new phenol hydroxylation process.It's suitable for continuous production,and the separation of catalyst from product is relatively easy.Also,It's more green and energy saving than traditional process.The specific research contents are as followed:1.The exploration of the kinetic of the self decomposition of H₂O₂ on TS-1molecular sieve catalyst.It's found that hydrogen peroxide concentration has a linear relationship with reaction time.The decomposition reaction of hydrogen peroxide on TS-1 molecular sieve catalyst is zero order,and the activation energy Ea=28.14kJ/mol.2.The exploration of the kinetic parameters of hydroxylation of phenol with hydrogen peroxide on powder catalyst.The effects of reactant concentration and temperature on phenol conversion and product distribution were investigated,and polymath software was used to fit dynamic parameters of regression reaction.The results shows that hydroxylation of phenol with hydrogen peroxide on TS-1 molecular sieve catalyst is 1.18 for phenol,1.15 for hydrogen peroxide,and total reaction activation energy is 31.99kJ/mol.3.The exploration of the macro kinetics of phenol hydroxylation with hydrogen peroxide on TS-1/cordierite monolithic catalyst.Using Aspen software,a batch reactor model was built based on TS-1/cordierite catalyst,and macro kinetics was explored with the experimental data on the reaction kinetics of the ordierite catalyst.The results show that the internal diffusion resistancecan not be ignored on the surface of the TS-1 zeolite layer,and the effective diffusion factor in catalyst a=0.765.4.According to the characteristics of hydroxylation of phenol on TS-1/cordierite monolithic catalyst,an internal circulation loop reactor was designed.This monothlic reactor with internal circulation of the reacting mixture has the many advantages over the traditional batch reactor,such as increasing the retention time of the reactant on the catalyst,reducing the external diffusion resistance,preventing excessive oxidation,separating the catalyst from the product and continuous production.5.Using Aspen software to establish a process model of hydroxylation of phenol to dihydroxyl phenol.The simulation results shows that under the same conditions,the results of simulation is similar to that of the experiment,and the simulated value of phenol conversion is 93.6%of the experimental value.After the comparison of various separation processes,the extraction combined distillation process is selected,36.4%energy saving can be reached up compared with the common distillation,and a large amount of azeotropic agent in the relative azeotropic distillation can be saved.6.Using Aspen software to establish a continuous hydroquinone production process based on 3500 t/a phenol and TS-1/cordierite monolithic catalyst.And he process parameters are simulated and optimized.Compared with the traditional process,the conversion rate of phenol and the selectivity of the product are higher,and it does not need complex filtration system to recover the catalyst;the reaction process is continuous operation,and the extraction combined vacuum distillation can save energy and reduce consumption.