Pharmaceuticals green solvents

Table 7.4. Green solvents applicable to pharmaceutical field. (Ash and Ash, 1996).

Along with methods to evaluate different pharmaceutical processes and unit operations, several methods have also been developed to evaluate commonly used solvents in the pharmaceutical industry. Solvents still account for a majority of the mass utilization in any pharmaceutical process. Therefore, various methods have been developed which focus on measuring the greenness of solvents, locating possible alternatives and reducing the overall amount of solvent used in any given process. Some of these methods use a combination of physical property data, LCA... 

Besides only as green reaction media, ionic liquids as dual green solvents and catalysts are also widely used in acylation reactions, especially C-acylation. Benzophenone and its derivatives are important fine chemicals or intermediates in dyes, pharmaceuticals, and other chemical industries. Li et al. have studied the Friedel-Crafts acylation reactions using ionic liquids like BMlMCl-FeClj, BMIMCI-AICI3, and BMIMCl-ZnCl as dual catalyst-solvent to synthesize benzophenone and its derivatives. They found that BMIMCl-FeCl3 showed much higher catalytic activity than that observed for the other two ionic liquids, and in conventional organic... 

Succinic acid, known as amber acid or butanedioic acid, is a four-carbon dicarboxylic acid produced as an intermediate of the tricarboxylic acid cycle (TCA) [1,2]. Succinic acid and its derivative have wide industrial applications such as the feedstock of food and pharmaceutical products, as the intermediate of chemical synthesis of surfactants, detergents, green solvents, and biodegradable plastics, and also as ingredients of animal feeds to stimulate animal and... 

Lactic acid is known to have numerous fields of industrial application, such as foods, cosmetics, pharmaceuticals, textiles and chemicals (Wee et al. 2006). Via simple chemistry, lactic acid can be converted into lactic acid esters that constitute so-called green solvents. In the area of polymers, lactic acid opens the route for the chemical production of PLA and the biotechnological production of PHA (see Fig. 6). 

Ionic liquids A new strategy in pharmaceutical synthesis 12MRO203. N-Heterocyclic carbenes in room temperature ionic liquids as green solvent—catalyst systems 13COC204. 

Lactic acid has been used in the food, chemical and pharmaceutical industries for years, and has the potential to achieve commodity-level status as an intermediate for oxygenated chemicals, "green" solvents, specialty chemical intermediates, and polylactic acid (PLA). PLA, which is already used in medical devices, holds great promise for increased use as a versatile, environmentally-... 

As has been noted previously, NADES composed of natural compounds are sustainable and biodegradable and exhibit an acceptable pharmaceutical toxicity profile and a high solubilization power of substances of diverse polarity. It is all these excellent characteristic features that have made NADES very interesting alternatives to the currently used toxic organic solvents and synthetie ILs. NADESs hold a tremendous potential of applications they can be utilized as truly green solvents for extraetions, synthetic organic chemistry, and enzymatie reaetions. 

These criteria are widely applied for the selection of conventional solvents in the process development and manufacturing. Nowadays, a new generation of solvents intervenes in the medicinal chemistry and pharmaceutical industry. These solvents have eco-friendly character and together with water compose an expanding family of green solvents [4-7]. 

Heferocycles are a class of compoxmds especially relevanf in the life processes through their enzymatic fxmctions and the hereditary information transfer they also find applications in medicine, agriculture and industry, and in different areas of the chemistry. Heterocyclic compounds are often used in nanochemistry, molecular devices and sensors, combinatorial and supramolecular chemistry, and also in catalysis [8]. Furthermore, an important type of ionic liquids (ILs) useful in the pharmaceutical industry, which can act both as green solvents and catalysts, are composed of heterocyclic compoxmds [9,10]. 

Villanueva et al. reported a comparison between the performance of different green solvents for extracting thymol from different thyme plants. The genus Thymus (Lamiaceae family) is an aromatic plant very rich in essential oil compounds, which are the most valued constituents of the herb. Thyme essential oil is formed by terpenes and its oxygenated derivative compounds (alcohols, aldehydes, ketones, etc.) and is appreciated for food flavoring, in cosmetic, perfumery and in the pharmaceutical industry. 

These environmentally friendly properties lead to the concept of Green Chemistry , manifested in the appearance of a journal of the same name, published by the Royal Society of Chemistiy. All various aspects of ILs including their use in catalysis, biotechnology, polymer chemistry, solar cell construction, chemical kinetic, etc. have been discussed in many books. It has become clear that it is possible to create specific compositions of various ILs exhibiting various physical, chemical, biochemical and pharmaceutical properties. Terms such as tuneable green solvents have been used to describe these possibilities. Within the last 20 years the number of publications dealing with ILs has tremendously inereased. Several excellent reviews on the development of ILs, their history as well as on their expanding applications are available. ... 

---