It is necessary to eliminate the possibility of contamination of the starting materials and/or products of other materials and products. Increased risk of accidental cross-contamination contributes to the uncontrolled spread of dust, gases, vapours, aerosols or micro-organisms present in the materials and products, equipment, and clothing (Coyle, et.al, 2004, 179-186). The degree of risk depends on the type of contamination and product exposed to contamination. The most dangerous pollutants are sensitizing substances, biological preparations containing living organisms, certain hormones, cytotoxics and potent substances (Pye & Blott, 2009, 170-181). Contamination is particularly dangerous for drugs used for injection or for the treatment of open wounds and also intended for prolonged use and/or receiving high doses.
• it is a dehydrating agent ( allow the reaction to move forward towards ester formation ) . 2) The usage of dehydrating agents ( as CaCl or MgSo4) to remove excess water molecules trapped in the ester layer . B) Synthesis of ester using acetic anhydride :- 1- Add 2-3 ml of acetic anhydride in a large dry test tube then add 3 drops of concentrated sulphuric acid and mix. 2- Get any one of these alcohols (1-propanol, 3-methyl-1- butanol, benzyl alcohol, or 1-octanol) in a small dry test tube . 3- Put the large tube in an ice bath and start to add alcohol by an increasing rate .
Extraction is the process of separating substance from one phase by another phase. It is often used as one of the steps in isolating a product of an organic reaction. A separatory funnel would be used for the isolation from the mixture. A solvent will be used to remove or isolate a compound of interest from a liquid substance. In most cases, water was used as the solvent to the reaction mixture to dissolve the inorganic compound.
Bio-diesel production yields undesirable by-products for example methanol and glycerin. These by-products are removed so that the bio-diesel is suitable for use. Fractional distillation is used in the essential oil, flavor and fragrance industry. Raw essential oils are extracted from different plants such as mint, clove and tee tree for example. These raw oils contains impurities that have a bad flavour or odor.
The developing chamber for the TLC plates was prepared by adding ethyl acetate that contained 0.5% acetic acid to the glass jar. The TLC plates were prepared by drawing a horizontal line from bottom margin (0.5cm) where the four spots were placed. Separate small capillary tubes were used to spot solutions of Tylenol, Anacin, acetaminophen and acetylsalicylic acid respectively on the drawn line. The spotted TLC plate was placed in the developing chamber (glass jar) ensuring the solution in the glass jar is below the drawn line, followed by covering the top of the glass jar(Qui, Haixing, and Yusheng
The oxidation products are known to be health hazards and are linked to aging, cancer and heart disease. The double bonds of -3 fatty acids are highly prone to oxidation due to their large number and position in the fatty acid chains. Initiators such as light, heat, oxygen and transitional metals produce lipid radicals and lipid peroxides leading to formation of conjugated dienes and trienes through cis-trans isomerization processes and shifts in the double bonds.  The unstable lipid peroxides further degrade to form more harmful secondary oxidation products such as carboxylic acids, ketones and aldehydes (e.g. cis-4-heptenal, (Z,Z)-3,6-nonadienal, (E,Z)-2,6-nonadienal) which cause the undesirable odor and taste associated with rancid oil.
Nitroaromatic compounds are the major group of pollutants because they enter into environment in large quantities, are toxic and resistant to degradation and bioaccumulate. Nitroaromatics such as nitrobenzene, nitrotoluenes, nitrophenols, nitrobenzoates and nitroanilines are extensively used in industry for the manufacture of pesticides, explosives, dyes, plastics and pharmaceuticals. There are reports of widespread contamination of soil, water and atmosphere by nitroaromatic compounds. Nitrotoluenes are used in the large scale manufacture of explosives such as 2,4,6-trinitrotoluene (TNT), which has led to the contamination of soil. Environmental pollution by Nitroaromatic compounds Nitroaromatics are stable, persistent, toxic and mutagenic and many of them are suspected or recognized carcinogens (Lotufo et al., 2009; Marvin-Sikkema and de Bont 1994; Nishino et al., 2000; Padda et al., 2003; Purohit and Basu 2000; Reiger and Knackmuss 1995).
Purpose/Introduction The process of recrystallization is an important method of purifying a solid organic substance using a hot solution as a solvent. This method will allow the separation of impurities. We will analyze Benzoic Acid as it is dissolved and recrystallized in water and in a solvent of Methanol and water. Reaction/Summary In Experiment One we will be recrystallizing Benzoic Acid from water. In Experiment Two we will be recrystallizing Benzoic Acid using a solvent pair made up of Methanol and Water.
Water contamination is one the world wide problems, which is directly affecting living organisms. There are several variety causes water pollutants like synthetic dyes used for textile dyeing, paper, plastics, leather, food, cosmetic industry, and other printing industries that causes severe ecological problems, because of their unacceptable color, biological degradation, toxicity, and carcinogenic properties, they are of great concern.. In order to solve this problem, many of researchers have developed some methods to degrading harmful dye from contaminated water like adsorption, flocculation, electrolyte decomposition, ion exchange method, biological methods, etc. These conventional methods are not suitable at large scale due to high
aquatic organisms and disturb the integrity of the ecosystem (Mester and Tien 2000; Puvaneswari et al., 2006) by alters the pH, increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD).Dyes industries have also a serious role in environmental pollution. Dyes mainly used in paper, textile and leather industries. Pollutant released from these dyes industries cause water and soil pollution. Water and land pollution by dyes industries affect large numbers of people and environment. These pollutants affects in many forms.