PARTITIONING OF CARBOHYDRATES IN THE VAPOR-LIQUID-LIQUID REGION OF THE 2-PROPANOL PLUS WATER PLUS CARBON-DIOXIDE SYSTEM

Partitioning of five carbohydrates in the vapor-liquid-liquid region o f the 2-propanol+water+carbon dioxide system has been investigated exp erimentally. Phase compositions of all three coexisting phases have be en determined at temperatures between 325 and 343 K and pressures betw een 9 and 13 MPa. The experimental method was checked by measuring vap or-liquid-liquid equilibria (VLLE) in the ternary subsystem 2-propanol +water+carbon dioxide and by comparing the results with the literature . In contrast to recently published experimental data of VLLE in the g lucose+acetone+water+carbon dioxide system, adding carbohydrates to th e 2-propanol+water+carbon dioxide system causes a significant extensio n of the VLLE region to lower pressures. With increasing pressure at c onstant temperature and decreasing temperature at constant pressure, t he composition of the middle phase becomes more similar to the composi tion of the gas phase. Simultaneously, the capacity of the middle phas e for carbohydrates decreases and the selectivity for different carboh ydrates increases. (C) 1997 Elsevier Science B.V.