ABSTRACT J-FOR Journal of Science & Technology for Forest Products and Processes: VOL.2, NO.4, 2012 38 From a biorefinery perspective, acetic acid, the most important carboxylic acid with numerous industrial applications, can be produced in an unconventional way from xylan acetyl groups during the pre-hydrolysis stage of Kraft-based dissolving pulp production. Recovery of acetic acid from pre-hydrolysis liquor (PHL) is challenging. In this research, an attempt was made to separate acetic acid from a 1% aque- ous model solution (MAA), PHL, and activated carbon-treated PHL (TPHL) by a reactive extraction process to observe the efficiency of the system. The extractant tri-octyl amine (TOA) dissolved in diluent octanol was able to extract 80.48%, 61.84%, and 63.53% acetic acid from MAA, PHL, and TPHL respectively at a stoichiometric ratio of acetic acid to amine of one. A higher amine-to-acid stoichiometric ratio recovered more acetic acid, but at a lower loading factor. A possible reason for lower recovery of acetic acid from PHL than from MAA was investigated based on model compounds using furfural, acetic acid, syringyldehyde, and xylose. The extraction efficiency was improved slightly when furfural and lignin were removed by activated carbon treatment before reactive extraction. It was noted that reactive extrac- tion was highly specific to acetic acid because furfural and lignin showed high affinity only towards octanol and that sugar remained almost unaffected in the system. LABONI AHSAN, M. SARWAR JAHAN, HAITANG LIU, YONGHAO NI* RECOVERY OF ACETIC ACID FROM PRE-HYDROLYSIS LIQUOR OF A KRAFT-BASED DISSOLVING PULP PRODUCTION PROCESS BY REACTIVE EXTRACTION WITH TRI-OCTYL AMINE (TOA) AND OCTANOL Acetic acid is an important raw material for many other value-added products like terephthalic acid, vinyl acetate monomer, acetic anhydride, esters, and mono-chloro- acetic acid in the chemical, pharmaceuti- cal, food processing, and textile industries. One survey performed by Global Indus- try Analysts, Inc. of California in 2011 reported that global demand for acetic acid will reach 11.3 million tons by 2015 (http://www.prweb.com/releas- es/2011/1/prweb8049448.htm). The pre- hydrolysis liquor (PHL) from a Kraft-based dissolving pulp process contains approxi- mately 10–11g/L acetic acid and can be a substantial source of this carboxylic acid [1]. The main purpose of pre-hydrolysis is to remove hemicelluloses before wood is pulped to produce dissolving pulp. These hemicelluloses are partially bound by INTRODUCTION acetyl groups (approximately 5% of total wood constituents), which are converted to acetic acid under high temperature and pressure in the presence of steam, water, or both during the pre-hydrolysis process [2]. These hemicelluloses (5.03%) in PHL may be converted to ethanol by fermen- tation [1] or to other products such as furfural. However, the presence of acetic acid inhibits fermenting microorganisms and may severely decrease ethanol pro- duction [3]. Therefore, the separation of acetic acid along with furfural and lignin from PHL is a crucial recovery stage for utilizing these valuable chemicals as well as reducing the inhibitor load in the produc- tion of ethanol. Various methods have been used to sepa- rate acetic acid from different process streams, including most commonly resin treatment, adsorption processes, liquid- liquid extraction, and membrane separa- tion. The present research focused on reactive extraction because of its selectiv- ityand efficiency. In conventional liquid-liq- *Contact: yonghao@unb.ca YONGHAO NI Limerick Pulp and Paper Centre, University of New Brunswick, Fredericton, N.B Canada SARWAR JAHAN Pulp and Paper Research Division, BCSIR Laboratories, Dhaka, Dhaka-1205, Bangladesh HAITANG LIU Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science and Technology, Tianjin 300457, P.R. China LABONI AHSAN Limerick Pulp and Paper Centre, University of New Brunswick, Fredericton, N.B Canada