Equilibrium constants for the liquid-phase synthesis of methyl ferf-butyl ether (MTBE) were determined experimentally In the temperature range 40-80 °C. Equilibrium was established In the methanol addition to Isobutylene for obtaining MTBE over the sulfonic acid resin Lewatlt SPC 118 as the catalyst In a batch reactor maintained at 1.8 MPa. The experimental equilibrium constant Is given as a function of temperature, and enthalpy, free energy, and entropy changes have been determined as well. At 298 K, H°= -38.0 ± 0.8 kJ mol'1, AG°= -13.8 ± 0.8 kJ mol"1, and AS0 = -81.7 ± 0.5 J mol-1 K'1. The UNIFAC estimates of activity coefficients have been used to describe the liquid-phase nonideality. A comparison of experimental, thermodynamic, and literature data has been carried out.

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The liquid-phase addition of ethanol to isobutene to give ethyl tert-butyl ether (ETBE) on the ion exchange resin Lewatit K2631 has been studied. Rate data were obtained free of mass transfer influence in a continuous differential reactor operated at 1.6 MPa and 40-90 "C, measuring steadystate conversions

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Alkyl levulinates are biobased chemicals with a great number of applications and great biofuel potential for blending to conventional diesel or gasoline. The present work focuses on the liquid-phase synthesis of butyl levulinate (BL) by esterification of levulinic acid (LA) with 1-butanol (BuOH) using a set of acidic ion-exchange resins. Experiments were performed at 80ºC and 2.5 MPa in a batch reactor by using an initial molar ratio AL/BuOH of 1/3 and a catalyst loading of 0.8%. It has been found that BL could be successfully obtained over ion-exchange resins with a selectivity higher than 99.5%. LA conversions ranged from 64% (Amberlyst 46, macroreticular, surface sulfonated) to 94% (Dowex 50Wx2, gel-type resin, conventionally sulfonated) at 8 h reaction time. By comparing their catalytic behavior, it was seen that resins morphology plays a very important role in the synthesis of BL making easier the access of reactants to acid sites. Accessibility of LA and BuOH to acid centers was high over highly swollen and low polymer density resins. Thus, gel-type resins with low divinylbenzene (DVB) content have been found as the most suitable to produce BL, e.g. Dowex 50Wx2, Dowex 50Wx4 and Purolite® CT224. Among them, Dowex 50Wx2 (2% DVB) is the most efficient catalyst tested.