Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite

Abstract

(2016) Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite. Catalysis Science and Technology, 2016 (6). pp. 5590-5598. ISSN 2044-4761 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/33644/1/ZhangHL%20Catalysis%20Science %20%26%20Technology%202016%20online.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Sulfonated cation exchange resins (s-CER) have been widely studied as a replacement of liquid acids for the catalysis of esterification of free fatty acids (FFAs) to produce biodiesel with water as the only by-product. However, the water produced has strong affinity to sulfonate groups in s-CER, which blocks the reactive sites for esterification and thus reduces the activity of the catalyst. To overcome this technical barrier, we have designed an s-CER/PVA composite by incorporating s-CER fines within a poly (vinyl alcohol) (PVA) matrix. PVA has much stronger absorption preference of water than s-CER and has very low selectivity for the reactants (FFAs and methanol), which enables the continuous removal of the produced water and liberation of reactive sulfonate sites in s-CER for catalysis. With s-CER/PVA, the FFAs conversion was increased from 80.1 % to 97.5 % after 8-hour reaction and the turnover frequency (TOF) was increased more than 3.3 times. The TOF of s-CER/PVA was also 2.6 times of that of sulfuric acid, suggesting that the water less, heterogeneous sulfonate sites are more reactive than water-blocked homogeneous ones. The reusability of the s-CER/PVA was also enhanced due to that the produced water that could cause deactivation of the s-CER was largely removed by PVA.

Facile synthesis of polyoxometalates tethered to post Fe-BTC frameworks for esterification of free fatty acids to biodiesel

“…52.3 kJ mol À1 , 78 kJ mol À1 , etc.). 45,46 Moreover, according to previous reported, 47,48 the esterication reaction is not diffusively controlled but kinetically controlled if the apparent activation energy is high enough (e.g., >20.0 kJ mol À1 ), and that the high apparent activation energy of esterication catalyzed by the PMA/Fe-BTC catalyst further demonstrates that diffusion is not important during our esterication processes. This nding suggests that the esterication reaction is chemically controlled and not by diffusion or mass transfer limitations.…”

Nanocarbon-based catalysts for esterification: Effect of carbon dimensionality and synergistic effect of the surface functional groups

“…The esterification mechanism of oleic acid with methanol catalyzed by strong acid catalysts containing -SO 3 H groups has been intensively studied [6,66,67] and is illustrated in However, when the weak acid group such as -COOH is added, the deprotonated form of -COOH could generate hydrogen bond with -OH group in the methanol molecule, providing a small portion of "negative charge" to the oxygen in methanol molecule. This "negative charge" in turn promotes the nucleophilicity of methanol molecule and hences the esterification reaction rate and conversion.…”

“…One way to reduce the cost of biodiesel is to use cheaper oil feedstock like waste cooking oils (WCO) [4,5]. The main disadvantage of using WCO as the raw material is that WCO contains a large amount of free fatty acids (FFAs) which normally react with the alkaline catalyst to form soap [6]. Therefore, the high free fatty acid contents in WCO have to be pre-esterified with methanol under the presence of homogeneous acid catalysts, such as sulfuric acid and hydrochloric acid [7,8].…”

“…In contrast, heterogeneous catalysis offer the advantages of easier separation, longer catalyst life, lower corrosion and more efficient recycling, thus reducing the overall production costs [9]. Versatile solid acid catalysts have been investigated spanning cation-ion-exchange resins [10], sulphated and tungstated zirconia [11,12], silica-based catalysts , zeolites [13], catalytic membranes [6,14,15], and carbon-based solid acid catalysts [2,[16][17][18][19].…”

Immobilizing Ni (II)-Exchanged Heteropolyacids on Silica as Catalysts for Acid-Catalyzed Esterification Reactions

“…In the production process, the expense of the raw materials is the major contributor to the cost of biodiesel production [7]. Thus, the low-cost oils are an economical raw material for the production of biodiesel, such as non-edible vegetable oils and waste oils.…”