Chemical operations

In this Dictionary 1 have aimed to provide an explanation of the terms used in the various branches of chemistry, together with brief accounts of important substances and chemical operations. The Dictionary is intended for use in schools, colleges and universities from the first study of chemistry up to about second year at university or college. We have necessarily had to be selective rather than comprehensive but most chemicals met with at this level should be included. 

To an experienced operator trained in the handling of industrial chemicals, the dimers present Httle cause for concern in handling or storage. The finished polymer coating presents even less of a health problem contact with the reactive monomer is unlikely. In the ancillary operations, such as cleaning or adhesion promotion, the operator must observe suitable precautions. Before using the process chemicals, operators must read and understand the current Material Safety Data Sheets, which are available from the manufacturers. 

N. A. Copeland and M. A. Youker, "German Techniques for Handling Acetylene in Chemical Operations," ELATEinalReport No. 720 (PB 20078), 1946 Includes translations of reports by Boesler, Rimarski, and Weissweiler. 

H. H. Faucett and W. S. Wood, Safety and Accident Prevention in Chemical Operations, 2nd ed., Wiley-Interscience, New York, 1982. 

Table 2 Hsts some of the physical, toxicity, flammabiUty, and reactivity properties of common chemicals (10,13,42,45—51). Also given are some of the quantities specified for reporting spills and for compliance with legislated requirements. The OSHA regulations require that material safety data sheets (MSDS) be developed for all process materials, so that the ha2ard data can be communicated to employees (52). Characteristics of toxicity, flammabiUty, chemical iastabiUty, reactivity and reaction energy, operatiag coaditioas, and corrosive properties of constmction materials must all be considered ia analy2iag ha2ard poteatials of chemicals and chemical operations.

R. D. Coffee, in H. H. Fawcett and W. S. Wood, Safety and Accident Prevention in Chemical Operations, 2nd ed., Wiley-Interscience, New York, 1982, p. 305 International Symposium on Runaway Reactions, Center for Chemical Process Safety, New York, 1989, pp. 140, 144,177, 234. 

L. V. Berman and M. L. Loeb in E. C. Leonard, ed.. The Dimer Jicids, Humko Sheffield Chemical Operation of Kraftco Corp., Memphis, Term.,... 

Natural dyes processed for the market do not undergo any chemical operations. Those operations iavolved are purely physical, such as grinding, spray or vacuum dryiag, and water or solvent extractions. None of these operations create any great environmental problems. 

Vacuum is used in conjunction with drying or other chemical oper-... 

Mineral black, a shale sometimes erroneously called rotten stone, contains a large amount of carbon and is used as a filler for paints and other chemical operations. It is pulverized and classified with the same equipment as shale, hmestone, and barite. 

Britton, E. G., 1999. Avoiding static ignition hazards in chemical operations, American Institute of Chemical Engineers, Center for Chemical Process Safety. New York. 

NFPA 1993 Standard on Support Function Protective Clothing for Flazardous Chemical Operations, 1994 edition. National Fire Protection Association, Quincy, MA. 

QRA is fundamentally different from many other chemical engineering activities (e.g., chemistry, heat transfer, reaction kinetics) whose basic property data are theoretically deterministic. For example, the physical properties of a substance for a specific application can often be established experimentally. But some of the basic property data used to calculate risk estimates are probabilistic variables with no fixed values. Some of the key elements of risk, such as the statistically expected frequency of an accident and the statistically expected consequences of exposure to a toxic gas, must be determined using these probabilistic variables. QRA is an approach for estimating the risk of chemical operations using the probabilistic information. And it is a fundamentally different approach from those used in many other engineering activities because interpreting the results of a QRA requires an increased sensitivity to uncertainties that arise primarily from the probabilistic character of the data. 

All chemical operations produce waste either as solid wastes (including pastes, sludge and drummed liquids), liquid effluents, or gaseous emissions (including gases, particulate solids, mists and fogs). Relevant data are summarized in Chapters 16 and 17. 

Mists and Sprays - There are numerous industrial chemical operations which involve liquid-in-gas dispersions. These operations generate mists and sprays that consist of particles in diameter ranges of 0.1 to 5,000 fim. Engineers most commonly encounter spray droplets which are particles often formed unintentionally in chemical plant operations. For example, vapors or fumes may condense onto piping, ducts, or stack walls. Under such conditions liquid films form. 

Cheremisinoff, N. P., Pressure Safety Design Practices for Refinery and Chemical Operations, Noyes Publications, Westwood, New Jersey, 1998. 

For a chemical operator, knowledge in the world is the upper and lower limits for a pressure reading shown on the log sheet, along with the response to take. A log sheet with only a blank to fill in the reading requires knowledge in the head. This contrast is shown in Table 6.1. 

TAG - Annualized fixed cost of modules -f Annualized fixed cost of pump -f Annualized fixed cost of turbine -H Annual operating cost of pump -h Annual operating cost of chemicals — Operating value of turbine... 

The reason for this is simple. If the reaction chemistry is not "clean" (meaning selective), then the desired species must be separated from the matrix of products that are formed and that is costly. In fact the major cost in most chemical operations is the cost of separating the raw product mixture in a way that provides the desired product at requisite purity. The cost of this step scales with the complexity of the "un-mixing" process and the amount of energy that must be added to make this happen. For example, the heating and cooling costs that go with distillation are high and are to be minimized wherever possible. The complexity of the separation is a function of the number and type of species in the product stream, which is a direct result of what happened within the reactor. Thus the separations are costly and they depend upon the reaction chemistry and how it proceeds in the reactor. All of the complexity is summarized in the kinetics. 

In order to locate items of interest in the book, the subject index lists, in addition to chemical operations, types of compounds rather than specific compounds (with a few exceptions). If, for example, readers do not find what they are looking for under the entry fluoroolefins , they may try olefins , double bonds, additions of , etc. 

Kazarians, M. and R. F. Boykin. Quantitative Risk Assessment for Chemical Operations. Proceedings of the International Symposium on Preventing Major Chemical Accidents, February 3-5, 1987, Washington, D.C. AIChE-CCPS, New York. 

An alternative source of the ethyl component was ethyl bromide, a less expensive material. It was at this point that GM called upon DuPont to take over process development. DuPont was the largest U.S. chemical company at the time. It had extensive experience in the scale-up of complex chemical operations, including explosives and high-pressure synthesis. The manufacturing process was undertaken by DuPont s premier department, the Organic Chemical section. GM contracted with DuPont to build a 1,300 pound per day plant. The first commercial quantities of TEL were sold in Februai-y 1923 in the form of ethyl premium gasoline. 

The precipitate must be convertible into a pure substance of definite chemical composition this may be effected either by ignition or by a simple chemical operation, such as evaporation, with a suitable liquid. 

Synaptic transmission is the transfer of biological information across synapses. Drugs that influence synaptic transmission play an eminent role in therapy, for two reasons. First, the nervous system controls all tissues. Second, with few exceptions synaptic transmission is chemical, operating by means of transmitter substances, and synapses therefore provide a large number of drug targets, such as the enzymes that synthesize the transmitter. However, the importance of... 

The molecular weights calculated in this way agree very closely with the so-called chemical molecular weights, derived from chemical analysis, and the method therefore rivals the latter in accuracy, without the attendant complications attaching to chemical operations with pure substances. 

The high chemoselectivity for the Baeyer-Villiger process was utilized in the synthetic elaboration of another hetero-bicyclic substrate. The biooxidation only provides the expected unsaturated lactone in a desymmetrization reaction without compromising the olefin functionality. The biotransformation product was then converted to pivotal intermediates for C-nucleosides like showdomycin, tetrahydro-furan natural products like kumausyne, and goniofufurone analogs in subsequent chemical operations (Scheme 9.17) [161]. 

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