289 PREPARATION OF POLYGLYCEROL FROM PALM-BIODIESEL CRUDE GLYCERIN NIK SITI MARIAM NEK MAT DIN*; ZAINAB IDRIS*; YEONG SHOOT KIAN* and HAZIMAH ABU HASSAN* * Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. E-mail: nsmariam@mpob.gov.my Journal of Oil Palm Research Vol. 25 (3) December 2013 p. 289-297 ABSTRACT The demand for green energy derived from plant feedstock has been the determining factor for the abundant supply of glycerol. Concerted eforts have been made to expand the current scope of glycerol application. This study describes the rapid polymerisation of crude glycerol directly obtained from the biodiesel process to produce polyglycerol via microwave heating technology. Crude glycerol used in this study was obtained from four diferent biodiesel pilot plants. Commercially pure glycerol was used as the control in all the parameters studied. The highest percent yield of polyglycerol obtained was 94.94% when heated at 250 o C for 60 min under microwave irradiation. Crude glycerol that gave the highest polyglycerol percentage was found to contain the highest percent of soap (12.5%). It was anticipated that a high conversion of glycerol was due to the soap contained in the crude glycerol. This study showed that biodiesel-based crude glycerol with appropriate soap content could be used directly as a raw material in polyglycerol production. Keywords: crude glycerol, polyglycerol, soap, dehydroplymerisation, microwave. Date received: 28 September 2012; Sent for revision: 14 December 2012; Received in fnal form: 13 June 2013; Accepted: 14 June 2013. INTRODUCTION The utilisation of glycerol for the synthesis of value-added chemical is a topic of great industrial interest because glycerol can be formed in large amounts during the production of biodiesel. For every 3 moles of methyl ester produced, 1 mole of glycerol is obtained as a by-product, which is equivalent to approximately 10% of the total product by mass (Smirnovs et al., 2008). Increasing demand of biodiesel will lead to larger amount of glycerol accumulated as by-products of which there is currently insufcient conventional use. Its efective utilisation will be a key factor to the success of biodiesel commercialisation and further development (Beltramini and Zhou, 2010). Crude glycerol generated during the biodiesel production process contains impurities such as methanol, water, inorganic salts (catalyst residue), free fatty acids, unreacted mono-, di- and triglycerides, methyl esters and a variety of other organic materials (Chiu et al., 2005; Yori et al., 2007). In order for biodiesel-based crude glycerol to be use in the industrial application such as for food, cosmetics, or pharmaceuticals, it requires expensive purifcation method. As a consequence, crude glycerol is claimed to be a waste with an associated disposal cost (Pinar Calik et al., 2008). Evidently, the development of new routes to convert crude glycerol into higher value products is very crucial. Crude glycerol has been studied with respect to wide range of felds such as combustion (Johnson et al., 2007), anaerobic digestion (Holm-Nielson et al., 2008), or feeding for various animals such as pigs (Kijora et al., 1996), broiler chickens (Simon et al., 1996), and laying hens (Yalcin et al., 2010). Altering crude glycerol into value-added products through thermochemical methods (Alhanash et al., 2008;