Kinetic modelling of hydrogen transfer deoxygenation of a prototypical fatty acid over a bimetallic Pd60Cu40 catalyst: an investigation of the surface reaction mechanism and rate limiting step

Herein, for the first time, we demonstrate a novel continuous flow process involving the application of tetralin as a hydrogendonor solvent for the catalytic conversion of oleic acid to diesel-like hydrocarbons, using an efficient and stable carbonsupported bimetallic PdCu catalyst. Using Pd60Cu40/C, where 60:40 is the molar ratio of each metal, at optimum reactionconditions (360 °C and WHSV = 1 h-1), 90.5% oleic acid conversion and 80.5% selectivity to C17 and C18 paraffinic hydrocarbonswere achieved. Furthermore, a comprehensive mechanistic based kinetic modelling - considering power rate law, L-H andE-R models was conducted. Kinetic expressions derived from the three kinetic models were investigated in rate data fittingthrough nonlinear regression using a Levenberg-Marquardt algorithm. Based on the statistical discrimination criteria, theexperimental data of the dehydrogenation reaction of tetralin was best fitted by an L-H rate equation assuming the surfacereaction as the rate controlling step. On the contrary, the kinetic data of the oleic acid deoxygenation reaction was wellcorrelated with an L-H rate equation assuming single site adsorption of oleic acid with dissociative H2 adsorption. It wasfound that the rate limiting step of the overall reaction was the hydrogenation of oleic acid with an activation energy of 75.0± 5.1 kJ mol-1 whereas the dehydrogenation of tetralin had a lower activation energy of 66.4 ± 2.7 kJ mol-1

Calculation of the molar heat of formation of fatty acid triglycerides from the heat of combustion of vegetable oils

The results of the research on estimation the molar heat of formation (enthalpy) of model triglycerides found in natural oils and fats are presented. In this work a calculation method and calorimetric one were used. It was found that combustion heat values determined by separate methods are comparable; their difference was a maximum of 155 kJ/kg, and thus was significantly lower than the tolerance for the calorimetric method according to PN 86/C-04062

Study of adsorptive materials obtained by wet fine milling and acid activation of vermiculite

Wet fine milling, as a pretreatment step to acid activation of vermiculite, was applied in order to decrease the environmental impact of the procedure commonly used to increase the mineral's adsorption capacity. Milling caused fragmentation of the material and several changes in its structure: edges of the flocks became frayed, the surface cracked, cation exchange capacity (CEC) increased, and most of the iron in oligonuclear and bulk form was removed. At the same time the specific surface area, crystallinity, chemical composition and adsorption capacity did not change significantly. Fine ground material was more susceptible to acid activation, which caused a decrease in the crystallinity and CEC, development of meso- and microporosity, an increase in the total volume of pores, in the specific surface and external surface areas. Micropores were developed faster in lower acid concentrations in the rough ground material, while the external surface area and total pores volume increased faster in the fine ground vermiculite. The latter material also had a higher CEC. Application of 0.5 mol L− 1 HNO3 to rough ground vermiculite did not change its adsorption capacity, however it changed from 55 ± 7 to 110 ± 8 mg g− 1 when the material was fine ground. The optimal treatment conditions for both materials were obtained for 1.0 mol L− 1 HNO3, however the adsorption capacity for the fine ground vermiculite increased more (i.e., from 55 ± 7 to 136 ± 7 mg g− 1) than for its rough ground counterpart (i.e., 52 ± 7 to 93 ± 7 mg g− 1). Concentrations higher than 1.0 mol L− 1 resulted in deterioration of the adsorption capacities in both cases. Considering all the experimental outcomes, it can be concluded that the environmental impact of acid activation of vermiculite may be diminished by application of fine grinding of the material before the chemical activation process. Such treatment resulted in higher adsorption capacity at a given acid concentration compared to the rough ground material.This work, within the scope of the project of Labóratorio Associado para Química Verde – Technologia e Processos Limpos – UID/QUI/50006, is financed by national founds of FCT/MEC and co-financed by Fundos FEDER (POCI-01-0145-FEDER-007265) within the scope of the partnership agreement PT2020. Part of the research was carried out with the equipment purchased thanks to the financial support of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (contract no. POIG.02.01.00-12-023/08). To all financing sources the authors are greatly indebted.info:eu-repo/semantics/publishedVersio

Zeoforming of triglycerides can improve some properties of hydrorefined vegetable oil biocomponents

Rapeseed vegetable oil was initially zeoformed in the temperature range of 200–300 °C and at a pressure of 1.7 MPa using a catalyst containing ZSM-5, and the obtained zeoformates were subsequently converted into hydrocarbons [hydrorefined vegetable oil (HVO)] through the process of hydroconversion. The resulting hydroraffinates (HVO fuel biocomponents) contained \mathit{n}-paraffins, isoparaffins, and up to 15% aromatic compounds. It has been established that hydroraffinates containing aromatic compounds have good low-temperature properties [cold filter plugging point (CFPP) of approximately −12 °C] and a density of 825 kg/m3. The hydroraffinate obtained over the catalyst at the highest applied temperature (300 °C) was characterized by a decreased initial boiling point of distillation (IBP) of 174 °C (the IBP for the non-zeoformed oil hydroraffinate was 284 °C) and an increased distillation final boiling point (FBP) of approximately 379 °C, which was higher than that of the non-zeoformed hydroraffinate (337 °C). Investigation of the obtained hydroraffinate properties led to the conclusion that the preliminary zeoforming process may cause the coupling (oligomerization) of fatty acid chains and the creation of aromatic structures containing aliphatic functional groups