Search

A technological purification procedure for obtaining a Cuban activated carbon is described. Characteristics of the obtained charcoal are similar to those corresponding to imported materials according to the following standards: United States Pharmacopeia 30, British Pharmacopeia (BP) and the Cuban National Standards. Results obtained during purification of Cuban activated carbon (M1) were compared with two imported materials as reference: USPXX Norit and RPCh. The first of these materials have been used during more than 20 years in the Cuban National Health System in cases of medical poisoning and as raw material in the preparation of coal and pepsin tablets for digestive disorders. Besides, the following comparative aspects were considered: physical chemical characterization, atomic absorption and ACP -AES analysis and specific adsorption: iodine number, molasses percent, methylene blue and strychnine. Technological procedure consists mainly of an acid leaching-base without heating, including filtration stages and very simple washings waters, as also recirculation of liquors of the process. Comparison results were statistically processed by a multiple range test and differences obtained were not significant (α = 0,05 %). It is an indication of the effectiveness of the purification procedure. Economic feasibility study offers favourable results in the indexes considered: NPV, IRR, EE, ROI, estimated price and production cost. All these results as a whole support the possibility of having in Cuba with a process and as a result of it, with a material of sufficient quality to replace imports in the short term. [ABSTRACT FROM AUTHOR]

In the synthesis of lactose acceptor that will be used to take part of oligisacarides and glicoconjugate it is necessary the protection of the 3',4' lactose positions with the isopropylidene group. In the chemical reaction, several collateral products are also obtained that must be separated from the isomer of interest. Two chromatographic column purifications and one final crystallization have been reported. In this work, the first chromatographic purification is replaced by two extractions: one liquid-liquid and one solid-liquid. Besides, an experimental design was also made to identify the best operation conditions for the extractions. In the liquidliquid extraction dichloromethane was used with a liquid-liquid ratio at level +1 and a stirring speed at level +1. The operation was repeated eight times. In the solid-liquid extraction, acetone was used with a liquid-solid ratio at level +1 and a stirring speed at level -1. The operation was repeated 12 times. The purification method described in the literature and the method proposed in the present work were compared, and both obtained similar amounts of the mixture of the 3 ', 4' and 4 ', 6' isopropylidene lactose isomers. Following the proposed method, the results are obtained in a shorter time and with a notable reduction in the consumption of reagents. [ABSTRACT FROM AUTHOR]

This paper presents the results obtained when Cuban bentonite impregnated with Cu(NO3)2 was used as catalyst in the conversion process of phenol into benzoquinone. With the application of this process lab operationss are practiced, and either efficiency and purification stages of the phenolic by products are improved. Physicochemical parameters of the oxidation product coincide satisfactorily with the forms benzoquinone (o-p). [ABSTRACT FROM AUTHOR]

El artículo examina un metodo cromatografico para la purificación de una proteina del bacteriófago VGJΦ de la bacteria Vibrio cholerae. Se describe la estructura de ADN monocatenario circular de la bacteria. Se hace una comparación entre dicho metodo cromatografico y la purificación electroforética, y los resultados de ambos metodos.