الملخص
resources for fuels and chemicals. Biomass transformation into fuels and value-added chemicals has gained extensive progress with number of successful commercial applications. It is clearly observed that catalysis is a key approach in the utilization of biomass. Sugar is one of the main components of biomass and used as a source for number of valuable chemicals. Isosorbide, also known as 1,4:3,6-dianhydro-D-glucitol, can be obtained from glucose and used a platform chemical for number of important industrial materials. The importance of this compound is that it contains two hydroxyl groups at positions 2 and 5, where it attains spatial structure exo in position 2 and endo in position 5. As a result, physical and chemical properties of the isomers are different, such as melting point and the reactivity of hydroxyl groups. Isosorbide is well known and its commercially available derivatives have important applications in many areas such as medicine, pharmaceuticals, polymers and plastic industry. There is also a serious health and environmental concerns over the use of phthalate plasticizers in plastic industry due to their toxicity. Therefore, the worldleading plastic manufacturers are seeking to develop safe and environmentally friendly plasticizers, particularly plastics with high thermal stability (thermoplastics). In this research, bio-based esters were prepared by esterification of isosorbide with a long-chain fatty acid (i.e. palmitic C16:0, stearic C18:0, Oleic C18:1, ricinoleic C18:1(OH) and sebacic C10:diCOOH). These acids were converted to acid chlorides as they are more reactive in the production of esters. By using heteropoly acids (HPAs), particularly, Tungstophosphoric acid H3PW12O40 (HPW), Molybdophosphoric acid H3PMo12O40 (HPMo) and cesium salts of 12-tungstophosphoric acid Cs2.5H0.5PW12O40 (CsPW). HPAs were selected for catalysis in this reaction due to their strong Brønsted acidity, high thermal stability, nontoxic crystalline material, safety and ease of handling. HPAs have significantly higher catalytic activity than mineral acids, the molar catalytic activity of HPA is often 100-1000 times higher than that of H2SO4. This makes it possible to carry out the catalytic reaction at lower catalyst concentration and/or at a lower temperatures...
