نتایج جستجو برای: organic solvents
تعداد نتایج: 235734 فیلتر نتایج به سال:
Baker’s yeast catalyzes the asymmetric reduction of prochiral ketones in water and in various organic solvents. The reaction in water, which is the first solvent of choice for bio-reactions, led to a high product yield and enantiomeric excess, but the low miscibility of organic molecules in water resulted in lower conversions when more hydrophobic ketones were used. Petroleum-based solvents suc...
Organic solvents are constantly present in the pharmaceutical production processes. They are usually used at any step of the synthesis pathway during the drug product formulation process. Organic solvents play an important role in the pharmaceutical industry, and appropriate selection of the solvents for the synthesis of drug substance may enhance the yield, or determine characteristics such as...
In recent years researchers have started to explore a particular class of organic solvents called room temperature ionic liquids - or simply ionic liquids - to identify their unique advantages for biocatalysis. Because they lack vapour pressure, ionic liquids hold potential as green solvents. Furthermore, unlike organic solvents of comparable polarity, they often do not inactivate enzymes, whic...
Various organic solutions are used in many industries such as the petrochemical industry. The presence of moisture in those solvents results in poor insulation, corrosion of apparatus and catalyst poisoning. Therefore, the moisture content of the solvents must be reduced to less than several ppm. Since ion exchange resins have an ability to adsorb selectively polar substances fromnonpolar solve...
Polymersomes are vesicular self-assemblies of amphiphilic diblock copolymers; they consist of a spherical compartment enclosed by amacromolecular bilayer and have great potential as encapsulation and release systems. They offer enhanced mechanical and structural stability as compared to vesicles made from phospholipids or detergents. By tailoring block lengths, block chemistry and functionaliza...
A high prevalence of sleep apnoea was found in a group of men occupationally exposed to organic solvents. Workers with long term exposure to organic solvents often report symptoms such as fatigue, forgetfulness, and concentration difficulties. These symptoms are strikingly similar to those reported by patients with obstructive sleep apnoea syndrome (OSAS). This is a frequently diagnosed disorde...
Over the past decade, a variety of ionic liquids have emerged as greener solvents for use in the chemical manufacturing industries. Their unique properties have attracted the interest of chemists worldwide to employ them as replacement for conventional solvents in a diverse range of chemical transformations including biotransformations. Biocatalysts are often regarded as green catalysts compare...
The dimensional variations of green wood samples induced by organic solvents have been studied. The solvents used (ethanol, isopropanol, acetone, and acetonitrile) covered a wide range of polarity and were studied pure and in aqueous solutions over a wide range of concentrations. Samples of normal and tension wood of poplar were used in order to minimize the effect of hydrophobic extractives on...
Some studies suggest that exposure to industrial solvents can affect blood pressure. The objective of this study was to investigate the effect of a mixture of organic solvents on blood pressure in women working in a pharmaceutical company in Iran. Four hundred and thirty-three women were included in the study. Women working in packing units (group 1) were not exposed to the mixture of organic s...
Exposure of workers to mixtures of organic solvents and to occupational noise is frequent in a number of industries. Recent studies suggest that exposure to both can cause a more severe hearing loss than exposure to noise alone. Our cross-sectional study included 411 workers of a large automobile plant divided in three groups. The first group included assembly workers exposed to noise alone; th...
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