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Download as many books as you like Personal use 3. Cancel the membership at any time if not satisfied. Markus Jensen I did not think that this would work, my best friend showed me this website, and it does! It uses sodium borohydride, sodium hydroxide, disodium ethylenediaminetetraacetic acid Na2EDTA , and sulfuric acid as reagents.
Because some water treatments only remove As V , monitoring and remediation require highly sensitive techniques that can measure As III and As V separately. Professor Dasgupta filed patent applications in and for this technology. A Green Process for the Synthesis of Quinapril Hydrochloride : Pfizer emphasized green chemistry objectives in redesigning its process to manufacture quinapril hydrochloride HCl , the active ingredient in the important cardiovascular medicine, Accupril TM.
The resulting process employs more efficient chemical transformations with dramatic environmental and worker safety improvements. The process has eliminated methylene chloride and dicyclohexylcarbodiimide. Operations that caused loss of yield due to the intermolecular cyclization of quinapril HCl have been minimized. The environmental and safety improvements are dramatic. The process has also eliminated the use of approximately 1, metric tons per year of methylene chloride.
Their nanoscopic size renders them VOC free while their hybrid "organic-inorganic" composition provides them with inherently low flammability and excellent oxidative stability. They dramatically improve the thermal and mechanical properties of traditional polymers while offering turnkey incorporation using existing manufacturing protocols.
They are biocompatible, recyclable as silica, and are competitively priced with traditional performance material technologies. A Microwave Oven Dissolution Procedure for a Ten Gram Sample of Soil Requiring Radiochemical Analysis : A microwave soil dissolution procedure was incorporated into a standard analytical method for testing soils for americium and plutonium. This modification displaces several hot plate dissolution steps by incorporating a microwave oven with new commercially available products.
The new procedure uses a commercially available microwave oven that has the capability to monitor and control the pressure and temperature of a control vessel using a feed back system. The ability to repeatedly obtain and control desired temperatures and pressures has resulted in improved analytical precision because the reaction conditions can be reproduced. This new procedure also reduces the consumption of hazardous substances, the amount of air pollution produced, worker exposure to hazardous substances, and sample preparation time.
The use of closed vessels in this modified procedure also results in reduced hazardous reagents use. Less reagents means less hazardous waste and air pollution are produced, and reduced worker exposure to the reagents. In addition, the use of the microwave oven reduces the time requirements from two to three days for the hot plate procedure to eight hours. A New Corrosion Inhibitor Reduces the Environmental Impact of Industrially Treated Water : Industrial water treatment systems suffer from the dual challenges of mineral scale fouling and ferrous metal corrosion.
Scale and corrosion result in loss of flow, leaks, and general wasting that lead to plant shutdowns, high capital costs, and unplanned maintenance charges. To minimize the impact of these failures, chemical scale and corrosion inhibitors are added to the water in industrial cooling systems. Chemicals traditionally used as scale and corrosion inhibitors include phosphates, polyphosphates, phosphonates, and treatments based on zinc or molybdate.
Concern for the environmental impact of metals and phosphates has led to increased oversight of the use of these materials. Broader implementation of discharge limitations is one means for reducing the impact of these chemicals on the environment, but it places industrial water users under greater burden to manage scale and corrosion in their water treatment systems. Nalco developed a new inhibitor for cooling water applications, phosphinosuccinic oligomer PSO , which has shown superior scale and corrosion protection.
PSO also reduces or eliminates the need for zinc, molybdate, and compounds that decompose to phosphate. The scale inhibition of PSO has led to more efficient water use because cooling systems use less water when they can operate at higher mineral ion levels. PSO functions as a cathodic inhibitor. It has replaced molybdate and zinc successfully in traditional corrosion inhibition treatment programs while providing a high level of corrosion protection.
The inhibitor is highly halogen-resistant. It does not revert to orthophosphate under normal conditions, allowing one to operate a cooling system with lower total phosphate levels compared with systems that use degradable polyphosphate. The cost and performance of PSO relative to traditional inhibitors have resulted in substantial reductions in the amount of zinc, molybdate, and phosphate used in water treatment.
Between and , Nalco increased its use of PSO by 77 percent. Exposure to corrosion inhibitors is thus a major concern. Conventional corrosion inhibitors used in industrial cooling systems are either hazardous to the environment or have other drawbacks, such as instability in the presence of oxidizing biocides, limiting their applicability. In many cases, the recommended treatment level is at least an order of magnitude below that which would be toxic to fish. The reaction is promoted by a novel catalyst-solvent system and is run under reactive distillation conditions. An ability to achieve near stoichiometric yields of DMC and ammonia has been demonstrated.
By recycling the ammonia to a urea plant in commercial practice, the net effect is to produce DMC from carbon dioxide and methanol. The commercial potential of the process has been evaluated by estimating capital and production costs for a large-scale plant and comparing the results with current state-of -the-art practice.
The latter is based on the reaction of methanol, carbon monoxide, and oxygen in the presence of a copper chloride catalyst. The new process has significant environmental and economic advantages. DMC is a on-hazardous alternative to phosgene currently used to introduce carbonate functionality into a variety of commercial products e. The projected low cost of the DMC produced by the new process should substantially increase its use as an alternative to phosgene. Further at the projected low price DMC has been proposed as an economic an environmentally benign alternative to MTBE as fuel oxygenate additive.
A New Process for the Manufacture of Pharmaceuticals : In an effort to reduce the amount of waste generated at its East Hanover site, Sandoz Pharmaceutical Corporation has evaluated all site processes in order to make improvements in the utilization of solvents and minimize the waste byproduct while also improving operating efficiency.
One process in particular was identified that appeared to offer significant opportunities for such process restructuring.
After 2 years of research, all the essential elements of the new process have now been demonstrated. The new process uses a single new solvent for both reaction medium and separation, which significantly reduces the overall solvent requirements and permits recycling of the used solvent by simple distillation.
As a result, the process waste index is reduced from the current Furthermore, the amount of solvent used per batch is cut in half, thereby significantly reducing the usage of solvent with attendant lower risks of worker exposure and accidental releases to the environment.
The decision to proceed with development of a new process, despite the potential problem of obtaining FDA approval of the process changes, is due primarily to the favorable economics of the new process. It is estimated that over 75 percent of the manufacturing savings are due to process improvements rather than disposal costs of unused solvent, illustrating the process optimization benefits characteristic for pollution prevention innovations.
The combinations of laropiprant with niacin MKA and with both niacin and simvastatin MKB have shown promising efficacy for the treatment of atherosclerosis and are currently being evaluated in late-stage phase III clinical trials. An enzymatic route was developed to prepare over 25 kilograms of material for early clinical trials. With optimization, this route would have been a satisfactory manufacturing process.
Merck chemists set out to reduce the environmental impact of the process significantly, however, by developing a new, highly efficient, asymmetric synthesis with green chemistry principles in mind. In realizing this goal, Merck researchers discovered two unprecedented transformations. The first was a novel extension to the classical Fischer indolization reaction to prepare indole ene acids in a one-step, highly convergent manner from readily available starting materials. The second was the development of a novel asymmetric catalytic hydrogenation of indole ene acids.
The new synthesis is convergent and highly atom-efficient, involves minimal extractions, distillations, or aqueous washes, and makes minimal use of protecting groups.
By implementing its new manufacturing route, Merck reduced its overall aqueous and organic waste production by 90 percent and 65 percent, respectively, compared with the enzymatic route. The technology discovered by Merck is an excellent example of the positive impact of scientific innovation on reducing the environmental footprint of a chemical process.
It also embodies the association between innovation in green chemistry and business benefits.
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