Study On The Alkylation Reaction Of Phenol-pyridine-indane And Distillation Simulation

Coal tar is one of the most by-products in the production of coking industry.In the medium and low temperature coal tar,phenol compounds are about 30%.We get the three component mixture system of phenol-pyridine-indane from separated phenols coal tar.In the three compoent mixture,phenol and pyridine have azeotropic temperature of 183.2^oC.The boiling point of indene is 177.9 ^oC and the boiling point is very close.Using ordinary distillation method could not acheive the separation of mixed component.But phenol could be carried out the alkylation reaction,by which of the phenol alkylation product was produced.The azeotropic composition of phenol and pyridine was broken and the relative volatility of indane was increased,and then realized the separation of the alkylation and pyridine-indane by the alkylation reaction.The separation route can also be used to obtain the product of phenol alkylation.Among all kinds of phenol alkylation products,tertiary butyl phenol is the most common.Tertiary butyl phenol is an important chemical intermediates,including2-TBP,4-TBP,2,4-DTBP,2,4,6-TTBP,which is mainly applied to surface active agent,antioxidant,coating and paint production,research on its synthesis has important significance.In this paper,we mainly studied the alkylation reaction of the three component mixture system of phenol-pyridine-indane and the separation simulation of the reacted system.The three component mixture system of phenol-pyridine-indane as raw material,tert butanol as alkylating agent,LXC-101,LXC-102 SO₃H acid resin as catalyst,the reaction of Liquid alkylation can be carried out in the fixed bed reactor,by which TBP was producted.In the experiment,the effects of reaction temperature,space velocity,and molar ratio of raw material to alkylation on the conversion of phenol and the selectivity of tertiary butyl phenol were studied.The optimized reaction conditions were as follows:the low temperature LXC-101 SO₃H acid resin catalyst,reaction pressure 1.0MPa,reaction temperature 85 ^oC,space velocity 50h^-1,the mole ratio of three component mixture and tert-butyl alcohol 1:3,the conversion rate of phenol can reach 81.9%and the selectivity of 2,4-DTBP is 48.4%.The high temperature LXC-102 SO₃H acid cation exchange resin catalyst,reaction pressure 1.0MPa,reaction temperature 105 ^oC,space velocity 100h^-1,the mole ratio of three component mixture and tert-butyl alcohol 1:3,the conversion rate of phenol is 91.5%and the selectivity of 2,4,6-TTBP is 62.1%.In this paper,the mixture after alkylation reaction being the raw material,the distillation separation was carried out.The distillation simulation was studied.Theoretical stages,column feed stage,reflux ratio and other parameters of the influence of the separation effect were studied.The optimum operating conditions as follow:in pretreatment distillation column,theoretical stages being 30,column feed stage being 14,reflux ratio being 2;in removed 2,4,6-TTBP distillation column,theoretical stages being 95,column feed stage being 44,reflux ratio being 12;in removed 2,4-DTBP distillation column,theoretical stages being 42,column feed stage being 16,reflux ratio being 4;in 4-TBP distillation column,theoretical stages being44,column feed stage being 10,reflux ratio being 7.Under the optimum operating conditions,we can obtain 2,4,6-TTBP and the mass fraction of 2,4,6-TTBP is 99.6%.We can also obtain 2,4-DTBP and 4-TBP and the mass fraction of 2,4-DTBP and4-TBP is 99.7%and 99.9%.