Green solvent or also known as bio-solvent is typically an alternative to the conventional solvents available in the market.It is an innovative idea of reducing the environ-mental impact resulting from the use of solvents in chemical production.
Currently, there are four methods of producing a green solvent namely:
- Substitution of hazardous solvents with ones that show bet-ter environmental, health and safety prop-erties. (Example: Ability to biodegrade or ability to reduce ozone depletion.)
- Production of solvents using renewable re-sources. (Example: Fermentation of agricul-tural waste to produce ethanol.)
- Substitution of organic solvents with environmentally harmless supercritical fluids.(Example: Usage of supercriti-cal CO2 instead of CFC.)
- Substitution of organic solvents with ionic liquids of low volatility. (Example: Lowering emission of volatile com-pounds to the atmosphere.)
Green solvent has a lower environmental impact com-pared to other conventional petroleum-based solvents. Be-sides,it has a host of advantages that gives it an added boost to edge out its rivals. Among them are:
- Completely biodegradable
- Can be recycled
- Non-ozone depleting
- Attractive solvent properties
- Produced from renewable re-sources
Since green solvents can be produced via a variety of processes as illustrated earlier, there are a variety of green solvents currently available in the industry.
- Ethyl lactate
- Siloxane polymer
- Dibasic esther
- Organic acid
Lactic acids are also known as milk acid and in the in-dustry, lactic acids are usually produced by lactic acid bac-teria such as Bifidobacteria and Lactobacillus via fermenta-tion. As lactic acid is mild in nature and non-toxic, it has been widely used in the production process of various types of products including cosmetics, pharmaceuticals and the likes.
With the advent of sustainable practice in the industry, lactic acids provide an avenue for scientists and entrepreneurs to utilize this chemical compound as a viable alternative to other forms of more toxic and hazard-ous materials. As such, lactic acid should be seen as the next great chemical alternative in the production processes of many of our everyday consumables.
Bioethanol has been the main focus in the biotechnol-ogy industry in recent years. It is a produced via fermentation of biomass by ethanol producing microorganisms and is con-sidered to be a form of renewable energy. A simplified chemical reaction can be seen below:
Ethyl lactate is more commonly produced through the esterification process of both lactic acid and ethanol. A sim-plified chemical reaction illustrating the esterification of lactic acid and ethanol into ethyl lactate is shown below:
The conversion of this reaction is limited by the chemi-cal equilibrium and in order to obtain a higher ethyl lactate yield, it is necessary to shift the reaction towards products for-mation.
Therefore, by removing one of the products from the reaction equation (usually the water), the equilibrium limita-tion can be overcome and the conversion can be driven to completion. This is due to the shift in the chemical equilibrium whereby a high purity of ethyl lactate can be obtained.