Estudou-se o comportamento polarográfico do telúrio (IV) em ácido cloridrico. No que se refere particularmente à reacção
de redução do Te(IV) a Te(0), admite-se que esta se possa dar em dois passos sucessivos de dois electrões, coin formação
de TeCl2(s) como intermediário. A interpretação dos dados experimentais obtidos faz-se também em termos das espécies
electroactivas presentes em solução.
A phenomenological theory for the concentration of dilute solutions by a rotary thermal diffusion column is presented, based on the development of a simplified (2-dimensional) model for the rotary column and subsequent application of Ramser's derivation for the «moving-walls» column.
A calculation method for multicomponent distillation is proposed which is based on the Lewis and Mathieson method for the plate to plate calculations. The convergence method used is based on the 0-method but involves only a single 0 irrespective of the number of sidestreams involved. The method is applicable in the case of multiple feeds, non-ideal mixtures and non-constant molal overflow and has been found converge satisfactorily on a variety of problems.
The Jetube is an oval shaped tubular reactor. Momentum exchange with the feed causes recirculation of the reactants, c times say, where c is typically 2 to 5.
Almost all the production of 1,2-diaminoethane, in industry, is carried out through the ammonolysis of 1,2-dichloroethane but there are always other ethylene amines with higher molecular weight being formed. This is certainly due to further reactions, namely 1,2-diaminoethane formed reacting with 1,2-dichloroethan
Trabalhos anteriormente realizados permitiram a elaboração de um modelo mecanístico geral para a reacção do buteno-1, em presença de oxigénio, sobre catalisadores de molibdato de bismuto. Desse modelo foi possível derivar equações cinéticas, tanto para a oxidação a butadieno como para as isomerizações.
Information used in the economic evaluation of a project is based on estimates and forecasts and is therefore uncertain. A realistic evaluation should take account of these uncertainties so that the consequential financial risks can be properly faced in making project decisions. This paper discusses problems in assessing the effects of uncertainty and describes the use of the computer-based technique known as risk analysis by which the logical consequences of subjective assessments of uncertainty can be explored. Recognition of the existence of uncertainty requires an explicit policy towards its risks and possible bases for such policies are considered.
