Biodiesel: a critical overview on the current status and perspectives at the academy and industry

This article presents a bibliographic review of research carried out on different alternative processes for biodiesel production. The supercritical and subcritical (non catalytic) reaction conditions, the use of solid basic, solid acid and other heterogeneous catalysts, including the use of immobilized enzymes and whole-cell catalysts are also critically compared with the traditional homogeneous alkaline or acid catalysts that are common on industrial applications. Advantages and limitations of all these processes for the transference from the laboratory to the industry are discussed. A correlation of the chemical composition with the quality parameters of the produced biodiesel is done with aim to stablish adequate procedures for the right selection of the raw-material. Castor bean oil is used as an example of inappropriate oil in order to produce a B100 that fulfill all the international physico-chemical quality standards. In this article are presented research results to adequate the values of viscosity, density and iodine number of the castor and soybean biodiesel to the international standard limits by means blending these both biodiesels at the right ratio

Crónica de uma mudança anunciada: o caso do banco Investimento

Apesar de pacífica a asserção de que a mudança é um processo organizacional necessário e um estado permanente de renovação e adaptação aos cada vez mais inusitados constrangimentos e estímulos internos e externos a que as organizações estão diariamente expostas, é por demais evidente a sua conotação negativa sendo não raras vezes percecionada e sentida de forma non grata. Veja-se, a titulo ilustrativo, as conclusões aferidas pelo estudo da consultora Ken Blanchard Companies (2008) referindo que entre 50 a 70% dos esforços de mudança não são eficazes e sobretudo falham, mesmo antes de serem plenamente implementados, ou então a metáfora enunciada por Cunha, Rego & Talone (2011) quando equiparam a mudança a uma guerra de trincheiras em que o “exército de agentes combate uma força de recetores pouco recetivos” (pg. 2).info:eu-repo/semantics/publishedVersio

One-pot synthesis of mixed (Z)-1,2-bis(organylchalcogene)-1-alkenes precursors of the novel beta-organylthio vinyllithium intermediates

One-pot hydrochalcogenation of 1-phenylthioacetylenes using organylselenolate and organyltellurolate anions generated by the insertions of selenium and tellurium in n-organyl lithium produced (Z)-1,2-bis(organylchalcogene)-1-alkenes. The chemical reactivity of these mixed 1,2-bis(organylchalcogene)-1-alkenes was studied by Te/Li and Se/Li stereoretentive exchanges carried out with n-butyl lithium, furnishing the new intermediate species (Z)-beta-organylthio vinyllithium anions, which were trapped with aldehydes, to give the (Z)-3-hydroxy vinyl thioethers with total control of the regio- and stereochemistry. (c) 2010 Elsevier Ltd. All rights reserved.CNPqCAPESFundacao Araucari