A Cleaner Production Process Of Tertbutyl Phenol

Tert-butyl phenols,including 2-tert-butyl phenol(2-TBP),4-tert-butyl phenol(4-TBP)and other derivatives,are important fine chemical products.Among them,4-TBP is an important raw material for the preparation of phenolic resin,fluorescent whitening agents,antioxidants,perfume,pesticides,and pharmaceuticals.2-TBP is widely used for the synthesis of fragrance,hindered phenolic antioxidants,flame retardants,high efficiency inhibitor and drugs.The current annual production of tert-butyl phenol is too low to meet the market demand in our country.Therefore,the supply of tert-butyl phenol mainly rely on imports.Tert-butyl phenol production processes in China are mainly sulfuric acid catalytic process and resin-based catalytic process.Such old process either has large energy and material consumption,severe corrosion of equipment and serious problems of wastetreatment,or the catalyst is unstable,which is hard to meet the demand of industrial production.Compared with the United States,Japan and other tert-butyl phenol production countries,the production technology and production capacity of tert-butyl phenol in China has yet to be improved.At present,the research on tert-butylphenol process mainly focuse on the development of new and efficient green catalysts.In this paper,the synthesis processes of 2-TBP and 4-TBP were explored and optimized at different levels by using Fe3+ modified activated clay as catalyst and phenol and tert-butanol as raw materials.In order to develop a kind of high efficiency and low cost industrial clean production process to produce 4-TBP or 2-TBP,the specific research contents and conclusions are as follows:(1)Establishing a reliable detection and analysis method for phenol and products,to lay the foundation for the optimization of synthetic technology.(2)The synthesis process of 4-TBP was optimized systematically to determine the optimum synthesis process conditions.With Fe3+ modified activated clay as catalyst,the optimum parameters were as follows:the molar ratio of phenol to tert-butanol was 6:1,the catalyst was 1.72 wt.%of the total raw material,the reaction temperature was 110 ? and the reaction time was 1.5 h.Under the reaction conditions above,the yield of target product 4-TBP was up to 72%or more.The result of the full-factor experiment showed that the molar ratio of phenol to tert-butanol had the greatest effect,and the high molar ratio was beneficial to the improvement of the yield of the target product 4-TBP.But the equipment capacity was reduced and the process cost was increased.The molar ratio of phenol to tert-butanol was further optimized by adding tert-butanol in batches.The results show that adding tert-butanol in batches can effectively reduce the molar ratio(which can improve the production capacity and reduce the process cost).The optimum process parameters were as follows:the molar ratio of phenol to tert-butanol was 4:1,and the feeding time of tert-butanol was 5 h.Under the reaction conditions,the yield of target product 4-TBP was up to 80%or more.Meanwhile,the result of the scale-up experiments showed that the effect of scale-up experiments was ideal.The experiment was carried out with 15 times scale-up,the yield of 4-TBP was up to 75%or more with the molar ratio of phenol to tert-butanol of 2:1,by adding tert-butanol in batches.The regeneration process of catalyst is simple and the recycling rate is high.The original catalytic activity and the high selectivity(yield)of the target product can be retained in recycle(more than 20 times).(3)Based on the 4-TBP production process,the active clay catalyst was further modified to improve the selectivity of 2-TBP by using phenol and tert-butanol as raw materials.The results show that the active clay catalyst can be effectively modified by high temperature calcination,and the selectivity of 2-TBP increased with the increasing of calcination temperature,within a certain calcination temperature range.The catalyst of AK-Fe(400)calcined at 400 ? was the best,and the selectivity of 2-TBP was 46.03%.Meanwhile,the organic modification of the sodium-based active clay with CTAB was also beneficial to improve the selectivity of 2-TBP.After modified by the organic method with CTAB,the active clay was further modified by calcination with high temperature.The selectivity of 2-TBP also increased with the increasing of catalyst calcination temperature,within a certain calcination temperature range.The catalyst of NaAK-O(500)-Fe-A calcined at 500 ? was the best,and the selectivity of 2-TBP was 45.85%.(4)Based on the optimum synthesis process of 4-TBP determined in this paper,the 4 t/d production process of 4-TBP systhesization catalyzed by Fe3+ modified activated clay,was designed to provide the basis for the industrial 4-TBP clean production process.