Jovita Moreno

Synthesis and characterisation of (hydroxypropyl)-2-aminomethyl pyridine containing hybrid polymer–silica SBA-15 materials supporting Mo(VI) centres and their use as heterogeneous catalysts for oct-1-ene epoxidation

Hybrid organic–inorganic amino alcohol containing PGMA–SBA-15 materials have been prepared by first tethering poly(glycidyl methacrylate) (PGMA) chains onto the surface of SBA-15 materials using the atom transfer radical polymerization (ATRP) technique. The procedure involves the functionalization of silica-based SBA-15 materials with aminopropyl groups and 2-bromo-2 methylpropionyl bromide to form ATRP initiator species. Subsequent graft ATRP of glycidyl methacrylate leads to a large decrease of the textural properties in the final material, but nevertheless, the use of the ultra large pore SBA-15 support is beneficial for the achievement of porous hybrid organic–inorganic materials. Reaction of the glycidyl pendant groups in the tethered PGMA chains with 2-aminomethyl pyridine allows the formation of the (hydroxypropyl)-2-aminomethyl pyridine ligands to which molybdenum(VI) species catalytically active for epoxidation of terminal alkenes are bound. The materials thus prepared display high catalytic activity and excellent stability and reusability in the epoxidation of 1-octene with TBHP as oxidant. The presence of mesoporosity in the final Mo(VI)-containing hybrid materials boosts the catalytic activity of supported metal centres.

Isosorbide Production from Sorbitol over Heterogeneous Acid Catalysts: Screening and Kinetic Study

The catalytic performance of two types of heterogeneous acid catalysts—sulfonic acid-functionalized materials and aluminum containing zeolites,—in the dehydration of sorbitol to isosorbide, in solventless and autogenous pressure conditions, has been studied. Catalysts screening evidenced strong differences between sulfonic acid-based materials and acid zeolites in terms of catalytic performance. Whereas sulfonic materials, such as Amberlyst-70 and SBA-15-Pr-SO3H, showed a very high catalytic activity, zeolites with beta structure evidenced good catalytic performance together with minimized promotion of side reactions (production of non-desired sorbitans, humins, etc.). Kinetic studies performed at different temperatures, adjusting to a Langmuir–Hinshelwood type model, allowed correlating the physicochemical properties of the acid materials with their catalytic performance in sorbitol dehydration. Thus, the analysis of initial selectivity through kinetic constants comparison indicated that commercial beta zeolite with a Si/Al ratio of 19 is the most selective catalyst for the production of isosorbide, though following a slower kinetics than the sulfonic materials. Furthermore, an equivalent hierarchical beta zeolite has been synthesised and evaluated, resulting in a slight improvement of the catalytic performance, in terms of both yield and selectivity to isosorbide. This improvement is attributed to the superior textural properties.

Quantitative Methods for Life Cycle Assessment (LCA) Applied to the Vegetable Industry

Nowadays there is a growing concern about the environmental effects produced by human activities due to natural resource depletion and ecosystem degradation. Traditionally, many industrial sectors have attempted to reduce the environmental impacts of their activities mainly by focusing their efforts on the improvement of manufacture procedures and operations carried out from the entry of raw materials in the factory to the exit of done products. However, for an adequate evaluation of the environmental performance of processes and products, it is necessary to think beyond the factory gate and understand the full life cycle of a product or an activity. Therefore, not only manufacture step should be taken into account but also other stages such as extraction and production of the required raw materials, packing and distribution of manufactured products, the use of products, the reuse or recycling processes and/or management of produced wastes. All these steps constitute the product life cycle, and the evaluation methodology that includes all of them is called life cycle assessment (LCA). Thus, life cycle assessment is considered a “cradle-to-grave” approach for the evaluation of industrial systems. In particular, systems for food production require larger inputs of resources and cause several negative environmental effects. Moreover, retailers are becoming very influential in addressing the environmental issue, exerting pressure on the food manufacturers to adopt sustainable manufacturing processes. Hence, sustainable processing is becoming increasingly important. A review of main LCA studies addressing environmental impacts in food industry, specifically in the vegetable processing industry, has been described. A “cradle-to-gate” case study considering as functional unit 130 g of packed RTE lettuce produced in Spain has been carried out. The main environmental burden obtained was associated with the processing phase (water used for lettuce washing; polypropylene used for packaging; and electricity consumed, mainly for cooling, in the processing plant), leading to emissions of 72 g CO2-eq affecting the global warming potential category.