The extracted organic layer was steam bathed to vaporize light petroleum which has low boiling point at 30-40˚C. Chromic acid is a more commonly used reagent for the oxidation of alcohols, it is a suspected carcinogen and generates hazardous waste. In green chemistry, innocuous chemical such as hypochlorous acid, HOCl will be used in oxidation, as to reduce the harmful waste. Green chemistry is the name given to modifications implemented in chemical manufacturing processes that ensure a safer and cleaner
As the water flows down and passes over a packing material possessing a large air-liquid inter phase, the volatile organic compounds (VOC) are transferred from the water to the air. It is effective in removing organic as well as inorganic contaminants including hydrogen sulfide. Distillation In this technology, water is heated until it turns to steam, which is then condensed as distilled pure water, free of most dissolved or any solid contaminants including bacteria and viruses. Because distilled water is free of all minerals, it may not be ideal for drinking. Ion Exchange This is a process is used commonly for water softening, by which ions that are dissolved in water are transferred to, and held by, a solid material or exchange resin.
Purification of brine The first step in the Solvay process is brine purification. This step is done to produce a pure sodium chloride solution. Brine contains impurities namely calcium and magnesium salts. Sulfates also can be found in some brines. These impurities have to be eliminated because they will produce unwanted insoluble salts by reacting with alkali and carbon dioxide, thus affecting the quality of the soda ash.
Ethylene and the catalyst promoter (HCl) are introduced into the reactor through sparges and effectively all ethylene is converted into ethylbenzene. Low ethylene and high benzene ratios are used in order to give desired yield of ethylbenzene. Most commercial plants operate at the ratio if 0.3-0.35 because as the ratio increased, more side reactions will occur such as transalkylation and isomeric rearrangement. Further alkylation of ethylbenzene will leads to formation of polyalkylbenzenes. The loss in net yield can be recovered by recycling the material to the alkylation
As such, it creates a stronger hydrogen bonding between H atom and O atom from carbonyl group of other carboxylic acids. FIGURE: The inductive effect of carbonyl compound is one of the contributing factor in high melting and boiling point. One of the special properties of the carboxylic acid is the dimerization of such chemical compound through hydrogen bonding when dissolved in non-polar organic solvent. FIGURE: Dimerisation in carboxylic acid Preparation of Carboxylic Acids There are several ways to produce carboxylic acids as most of chemical reactions of organic compounds are inter-related. Common examples of such preparation are oxidation of primary alcohol and aldehydes accompanied by the hydrolysis of Nitriles compounds.
The NaHCO3in solid state was used to neutralize the excess unreacted HCl(aq) while preventing unnecessary hydrolysis of the tert-butyl chloride which occurs in NaHCO3(aq) solution through the dissociation of the water solvent producing tert-butyl alcohol, the original reactant. The tert-butyl chloride product was then decanted into another dry Erlenmeyer flask. Anhydrous CaCl2 was used to dry the filtrate obtained and to remove the traces of unreacted alcohol in the solution as Ca2+ is an excellent complexing agent for oxygen containing compounds. Thereafter, the crude product tert-butyl chloride was decanted into a round bottom flask. A distillation set-up was prepared as shown in Figure 1.
Then, toluene is added with continuous stirring before transferring the mixture to a separating funnel. The two immiscible layers formed within few minutes. The transfer of metal salts from the aqueous phase to toluene then completes where ethanol is found to be very important candidate without which metal ions would not be transferred to the organic phase by the direct mixing of an aqueous metal precursor solution with an organic solvent containing dodecyl amine. The fact that water and ethanol are miscible ensures the maximum contact between metal ions and dodecyl amine. A large number of commonly used popular methods, e.g., wet chemistry reduction, seed mediated growth, co-reduction, and solvothermal approaches could be adopted to produce metal or semiconductor nanoparticles after the transfer into the organic solvent.
This process consists of suspending the drug particles in a low-melting polymer or wax and pumping the consequential slurry through an atomizer into a spray dryer in which cold air is circulated. The slurry droplets thicken on coming in contact with the air and are collected in the same manner as the spray-dried product. The spray congealing process requires a much higher ratio of coating agent to active material than does spray drying because only the molten coating agent constitutes the liquid phase. Encapsulation of drug-containing cores and granules (resins) in the manufacture of reservoir-type oral controlled released product can be accomplished by the following coating methods: 123-125 c) Pan Coating For encapsulation, Pan coaters are
However, in case of separation of solid impurities from liquid or liquids with high difference in boiling points Simple distillation can be preferred. Introduction Distillation is a specific technique of separating mixtures based on differences in propensity to vaporize of components in a boiling liquid mixture (Palleros, 2000). Distillation is a physical separation process, which does not involve chemical reaction and used for purification of liquids which do not undergo decomposition at their boiling point. There are several types of distillation including simple distillation, fractional distillation, vacuum distillation and steam distillation (ibid.). The type of used distillation depends on the nature of the liquid and the nature of impurities present in it.
Feedback control system regulates the rate of addition of lime by monitoring pH during addition. Lime is widely used for treating acidic wastes and is least expensive and the solution of excess lime do not reach extremely high pH values as solubility of lime in water is limited. Alkaline wastes could be neutralised by adding inexpensive acid, such as sulphuric acid. Acetic acid is preferable for some applications since it is nontoxic and biodegradable. Alkaline wastes can also be neutralised by bubbling gaseous carbon dioxide to form carbonic acid.