Wojcieszak et al. Sustain Chem Process (2015) 3:9 DOI 10.1186/s40508-015-0034-5 REVIEW Open Access Recent developments in maleic acid synthesis from bio‑based chemicals Robert Wojcieszak1*, Francesco Santarelli1,2,3, Sébastien Paul1,2, Franck Dumeignil1,4, Fabrizio Cavani3 and Renato V Gonçalves5 Abstract This review paper presents the current state of the art on maleic acid synthesis from biomass-derived chemicals over homogeneous or heterogeneous catalysts. It is based on the most recent publications on the topic, which are discussed in details with respect to the observed catalytic performances. The recent developments and the technical drawbacks in the gas and the liquid phases are also reported. In addition, recent results on the mechanistic aspect are discussed giving insights into the probable reaction mechanisms depending on the starting molecule (furan, furfural and 5-hydroxymethylfurfural). Graphical abstract: Keywords: Maleic acid, Heterogeneous catalysis, Furfural, Furan, HMF, Oxidation reaction, Nanomaterials Background nearly every field of industrial chemistry. Maleic acid is Maleic acid (MA) and fumaric acid (FA) are very impor- an important raw material used in the manufacture of tant chemical intermediates that find applications in lubricant additives, unsaturated polyester resins, surface coatings, plasticizers, copolymers and agricultural chem- *Correspondence: robert.wojcieszak@univ‑lille1.fr icals [1–5]. Fumaric acid is naturally present in many 1 CNRS UMR 8181, Unité de Catalyse et Chimie du Solide (UCCS), plants and its name originates from Fumaria officinalis, Université Lille 1 Sciences et Technologies, 59655 Villeneuve d’Ascq a climbing annual plant, from which it was first isolated Cedex, France Full list of author information is available at the end of the article [6]. It is used as a food acidulent and as a raw material © 2015 Wojcieszak et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Wojcieszak et al. Sustain Chem Process (2015) 3:9 Page 2 of 11 in the manufacture of unsaturated polyester resins, quick Fumaric acid is generally produced by fermenta- setting inks, furniture lacquers, paper sizing chemicals, tion [17–20]. Many aspects such as the applied micro- and aspartic acid [7, 8]. bial strain and its morphology, the use of a neutralizing Maleic acid and fumaric acid are dicarboxylic acid agent, and the applied feedstock play a crucial role in isomers that have the same carbon skeleton. They both the fermentation process. This latter is very interesting yield succinic acid (SA) by hydrogenation. Each can be because it involves CO2 fixation. Indeed, it is known that converted to the identical anhydride by heat treatment, the mechanism involving CO2 fixation and catalyzed by but maleic acid reacts much more rapidly. This, coupled pyruvate carboxylase enables obtaining higher yields in with the fact that mild hydrolysis of maleic anhydride FA production. In case of the maximum theoretical yield, (MAnh) leads to maleic acid, is linked to the cis structure two moles of CO2 could be fixed per mole of glucose con- of maleic acid and to the trans structure of fumaric acid sumed [19]. (Scheme 1). They contain two acid carbonyl groups and a The quest for sustainable and environmentally benign double bond in the α,β position. These functional groups sources of energy and, more recently, of chemicals has are very reactive, which makes the control of the selectiv- attracted much attention in the recent years [6]. The pro- ity of their synthesis reactions a key parameter. duction and the use of chemicals and fuels from biomass Historically, these two acids were first prepared in the [9, 21–23] seem to be an ideal solution to tackle environ- 1830’s, [9] but their commercial manufacture did not mental issues and fossil resources progressive depletion, begin until almost one century later. Maleic acid was if correct measures are taken. In that context, biomass- commercially available in 1928 and fumaric acid produc- derived platform molecules, such as maleic acid, fuma- tion began in 1932 using an acid-catalyzed isomerization ric acid or maleic anhydride have been identified as top of maleic acid process. value-added chemicals. Therefore, a highly effective Maleic anhydride can be commercially produced by method to produce these dicarboxylic acids from bio- the vapor-phase oxidation of benzene or butene/butane mass is necessary. Moreover, from the industrial appli- using O2 as an oxidant [10–15]. This later reaction is very cation point of view, this method should be simple and exothermic and CO and CO2 thus constitute the main by- environmentally friendly. In this context, heterogeneous products. The catalyst used in the production of maleic catalysis could bring new economic and environmen- anhydride from butane is vanadium–phosphorus-oxide tal solutions. Indeed, nowadays, new synthesis tech- (VPO). There are several routes to prepare this catalyst, niques permit to control the morphology and physical but the industrial way involves the reaction of vanadium and chemical properties of the catalysts. This yields in (V) oxide and phosphoric acid to form vanadyl hydrog- higher conversion rates and selectivities. In some cases enophosphate, VOHPO4⊕0.5H2O, which is then treated they are as good as for the enzymatic or homogeneous thermally to produce (VO)2P2O7. The catalyst used for catalysts. As a matter of fact, a better understanding of the conversion of benzene to maleic anhydride consists of catalytic nanomaterials is essential for the synthesis of supported vanadium oxide [16]. The vanadium oxide on fine chemicals. the surface of the support is often modified with molybde- In this review, we present the current state of the art on num oxides. The support is an inert oxide such as alumina maleic acid synthesis by upgrading biomass-derived mol- or silica of a relatively low surface area. The conversion of ecules (furfural and 5-hydroxymethylfurfural) using het- benzene to maleic anhydride is a less complex oxidation erogeneous and homogeneous catalytic processes. This than the conversion of butane, which enables obtaining paper is based on the most recent publications, and we very good conversions together with high selectivities [9]. put emphasis on the factors that have to be considered to Scheme 1 Chemical structures of maleic acid, fumaric acid and maleic anhydride. Wojcieszak et al. Sustain Chem Process (2015) 3:9 Page 3 of 11 understand the catalytic activity of the nanomaterials in This transformation could be achieved via oxidative C–C maleic acid synthesis. bond cleavage of HMF. Furfural is an important renew- able, non-petroleum based, chemical feedstock. It could Platform molecules used for MA, FA and MAnh be easily transformed into furfuryl alcohol (FAlc), via synthesis hydrogenation, which is a very useful chemical interme- Production of high value added chemicals from bio- diate [precursor of tetrahydrofurfuryl alcohol (THFA)]. mass sources remains one of the greatest contemporary It could be also transformed into maleic anhydride or challenges for heterogeneous catalysis. A very impor- maleic acid, via oxidation, as we will discuss later in the tant point to be analyzed is related to the choice of the present paper. The by-product of furfural oxidation in gas substrate and to its availability in the future. The major phase is furan. This molecule is also one of the important sources of this kind of raw material are agricultural resi- intermediates in chemical industry. Moreover, as indi- dues and wastes, such as rice straw, wheat straw, wood cated below, furan is also the first intermediate in the (hardwood), byproducts left over from the corn milling mechanism of the furfural oxidation. Even if it cannot be process (corn strover), annual and perennial crops, waste produced directly from biomass (it can be produced from paper and sweet sorghum. These raw materials comprise furfural) due to its presence in the reaction mechanism three types of main biopolymers: cellulose, hemicellu- we have decide to include it into the present review. lose, and lignin [24]. Biomass feedstocks are highly reactive by nature, and, Due to its numerous advantages for growth and pro- consequently, high temperature is normally not required duction, biomass raw materials has been identified as to achieve their transformation. However, reactions car- a suitable source of chemical energy for biofuels [25]. ried out in the liquid phase increases the possibility of However, in order to synthesize fine chemicals of the leaching issues. For this reason, rather than thermal sta- desired size and properties, catalytic C–C bond forma- bility, the new catalysts for biomass conversion should be tion is required. To this respect, 5-hydroxymethylfurfural designed so as to be resistant to leaching [29]. This is one (HMF), furan and furfural obtained by transformation of of the most important challenges in liquid phase hetero- carbohydrates, have been widely identified as useful plat- geneous catalysis. However, taking into account the huge form molecules [26, 27]. The respective chemical struc- number of paper on leaching issues, we think that this tures of these molecules are represented in Scheme 2. subject needs a separate review. That is the reason why The list of the most important building block chemicals we do not discuss on leaching phenomenon in details in (platform molecules) that can be produced from sugars this work. via biological or chemical conversions is now well estab- lished [28]. These building blocks can be subsequently Liquid phase oxidation: homogeneous converted to a number of high-value bio-based chemicals and heterogeneous catalysis or materials.