International Journal of Basic and Applied Chemical Sciences ISSN: 2277-2073 (Online) An Online International Journal Available at http://www.cibtech.org/jcs.htm 2013 Vol. 3 (4) October-December, pp.79-87/ Naniwadekar et al. Research Article 79 COST ESTIMATION & OPTIMUM ROUTE SELECTION FOR THE PRODUCTION OF ACONITIC ACID M. Y. Naniwadekar, *A. S. Jadhav, Ayan Ghosh, and Ashu Sahu Department of Chemical Engineering, AISSMS, COE Pune – 5, India *Author for Correspondence ABSTRACT Among the notable materials found in cane molasses there is, 1, 2, 3-propenetricarboxylic acid better known as aconitic acid. Trans aconitic acid (TAA) is the predominant organic acid in cane leaf matter (CLM) juice. TAA content ranged between 2.1-3.1 kg / t. Several resins, adsorbents & techniques were tested for their potential use in recovery of aconitic acid from a sugarcane liquor prepared by extraction and fermentation of the juice of sugar cane. There are three main techniques for the extraction of Aconitic acid from molasses namely, Precipitation (conventional method), Solvent-extraction, Ion-exchange method. The report is a detailed description of all the three methods. Our work also contains material balance for the ion-exchange method, design of fluidized bed ion exchanger, cost estimation for all the three methods and finally the optimum route selection. Key Words: Aconitic, Precipitation, Molasses, Trans Aconitic Acid (TAA) Fermentation INTRODUCTION Aconitic acid, (C 6 H 6 O 6 ), MW 174g/gmol, an unsaturated tribasic aliphatic acid exists in two geometric forms, the trans- isomer, TAA, and the cis- isomer. TAA is a white to yellowish crystalline solid, with melting point 195 °C. It is soluble in water and alcohol. Its solubility in water increases from 18.6 g/100 mL at 13 °C to 110.7 g/100 mL at 90°C. In sugarcane juice aconitic acid is present to the extent of 0.1% to 0.2% & its concentration goes on increasing, as the juice is concentrated to syrup stage & finally into molasses, it is present to the extent of 3%-7% on dry basis. MATERIALS AND METHODS 1.1 Precipitation Method Molasses were diluted to 50° Brix by adjusting the solution pH and adding the precipitation agent solution. The calcium hydroxide solution was added to the molasses to raise the pH from 6.2 to 6.8. Salt solutions of calcium chloride were prepared dissolving 7 to 11.5 g of CaCl 2 or 5 g of MgCl 2 in 120 mL distilled water according to the salt solubility. 250 g of treated molasses were introduced in the reactor and heated at 60 or 90 °C under reflux. Mechanic stirring (300 rpm) was applied during 30 min before adding the salt solution, which is the starting point of the precipitation reaction. After 1 or 7 h, stirring and heating were stopped and the reactor was cooled at room temperature during 1 h. The precipitated molasses were centrifuged 15 min at 5500 G. The tricalcium aconitate solid was washed with 150 mL of deionized water and centrifuged again. Finally, the solid was dried 12 hours at 106 °C. 1 g of the precipitate was dissolved in 30 mL of 25 % sulphuric acid, heated 30 min at 80°C under mechanic stirring, cooled 30 min in fresh water and filtered under vacuum to eliminate CaSO 4 solid wastes. Filtration cake was washed with deionized water in order to adjust the filtrate to 50 mL. First of all, precipitation was tested on model solutions. Once the optimal temperature, pH, CaCl 2 quantity and aconitic acid concentration were determined using Doehlert experimental design, experiences on molasses were carried out. 1.2 Model solution experiments Model solutions containing trans-aconitic acid from 1.5 to 4 % in mass were prepared and the pH was adjusted to 6.3 with a solution of sodium hydroxide at 12 % in mass. 250 g of the model solutions were introduced in a three necks reactor and heated under reflux about 15 min with stirring (300 rpm)