Catalytic distillation for esterification of acetic acid with ethanol: promising SS-fiber@HZSM-5 catalytic packings and experimental optimization via response surface methodology

BACKGROUND: Catalytic distillation (CD) is considered a promising green chemical process for numerous catalytic esterification reactions. Rendering novel structured CD packings is particularly desirable but remains challenging. RESULTS: A microfibrous-structured HZSM-5 solid acid catalyst is proposed as CD packing and its separation and esterification reaction efficiency for producing ethyl acetate from acetic acid and ethanol are demonstrated. Factorial design based on response surface methodology is employed for fast determination of optimum reaction conditions, which is working effectively and efficiently. Such structured catalyst packing is obtained by direct growth of zeolite onto the θ-ring analogues shaped from a microfibrous-structure consisting of 15 vol% 20 µm stainless-steel-fiber (SS-fiber) and 85 vol% voidage. CONCLUSION: The SS-fiber@HZSM-5 packing provides a unique combination of instantaneous distillation and desired catalytic properties with respect to stability, adequate acidic sites and high mass/heat transfer, and therefore works efficiently and effectively. High total (95.9%) and actual (90.9%) yields of ethyl acetate with 89.8% purity are achievable while the high CD efficiency was well-preserved after at least 240 h over 30 consecutive batch runs.