Reactive processes

Flame Retardants. Bromine compounds make up an important segment of the market for flame retardants used in polymers. Additive flame retardants are added to polymers during processing reactive flame retardants react chemically to become part of the polymer chain itself. In addition to the compounds Hsted in Table 3, a number of proprietary mixtures and phosphoms—bromine-containing flame retardants are also sold (see Elame RETARDANTS, HALOGENATED, FLAAffi RETARDANTS). 

Distribution of the monomer units in the polymer is dictated by the reactivity ratios of the two monomers. In emulsion polymerization, which is the only commercially significant process, reactivity ratios have been reported (4). IfMj = butadiene andM2 = acrylonitrile, then = 0.28, and r2 =0.02 at 5°C. At 50°C, Tj = 0.42 and = 0.04. As would be expected for a combination where = near zero, this monomer pair has a strong tendency toward alternation. The degree of alternation of the two monomers increases as the composition of the polymer approaches the 50/50 molar ratio that alternation dictates (5,6). Another complicating factor in defining chemical stmcture is the fact that butadiene can enter the polymer chains in the cis (1), trans (2), or vinyl(l,2) (3) configuration ... 

Experience has shown that reactive chemistry hazards are sometimes undetected during bench scale and pilot plant development of new products and processes. Reactive chemistry hazards must be identified so they can be addressed in the inherent safety review process. Chemists should be encouraged and trained to explore reactive chemistry of "off-normal operations. Simple reactive chemicals screening tools, such as the interactions matrix described in Section 4.2, can be used by R D chemists. 

In the presence of strong acid, formic acid decomposes to water and carbon monoxide. In the process, reactive intermediates form which are capable of direct carboxylation of carbonium ions. Since many carbonium ions are readily generated by the reaction of alcohols with strong acid, the process of elimination and carboxylation can be conveniently carried out in a single flask. The carbonium ions generated are subject to the... 

II. TECHNOLOGY FOR SOME PROCESS REACTIVE BLENDS PREPARATIONS... 

The process is operated in heated, batch reactors under an inert atmosphere. Two companies (Deeside Titanium, North Wales, and New Metals Industries, Nihongi, Japan) operate a one-stage process. Reactive Metals Industries Company, Ashtabula, OH, operates a two-stage process in the first stage, at 230°C, the trichloride and dichloride are formed. In the second, more sodium is added and the temperature is raised to 1,000°C. The sponge product is mixed with sodium chloride, which is leached out with dilute hydrochloric acid. Based on the work by M. A. Hunter at Rensselaer Polytechnic, New York in 1910. See also Kroll. 

In casting or processing reactive metals such as titanium, tungsten, and molybdenum, incidents have occurred in which molten metal contacted water. In some instances, explosions have resulted. There have been no published papers describing such accidents. ... 

In the RSDT process, the steps for infroducing cafalysf, ionomer, and carbon into the gas mix are decoupled and can be independently controlled in such a manner that the Pt/C and ionomer/C ratios can be continuously modified during fhe deposition process. Reactive spray deposition technology has the capacity and flexibility required to produce compositionally and... 

Eastern coal conversion development may come to be favored because of market proximity, water availability, and coal sources which, because of their high sulfur content, are currently unuse-able and, hence, largely decoupled from other energy prices. Proximity reduces transport costs and allows an increased use of low and medium Btu syngas processes. Reactivity and swelling problems may be overcome by technology. 

C. Blomberg, The Barbier Reaction and Related One-Step Processes, (Reactivity and Structure. Concepts in Organic Chemistry, Vol 31), Springer Verlag, Berlin-New York (1993)... 

Higgens, J., and Peterson, J. C. "Concept of Process-Reactive Schizophrenia A Critique," Psychological Bulletin 66, 201-6,1966. 

Each location shall have an appropriate and active reactive chemicals program. Regular reviews of process reactive hazards shall be required for existing processes, new processes and whenever key personnel or a process is changed, as well as a thorough review of laboratory or pilot plant data prior to scale-up. ... 

The so-called RIM-process (reactive injection molding) is a current realization of the reactive molding process. The heart of the process is the shock mixing of the reactive ingredients, which is achieved by collision of two jets injected at a pressure of 10 - 20 MPa. The reactive mixture is injected into the mold in a laminar flow regime the pressure at this stage does not exceed 0.1- 0.4 MPa.259 The practical development of this method relies on automatic control systems and modem high quality equipment. 

This chapter concerns the most important reactive separation processes reactive absorption, reactive distillation, and reactive extraction. These operations combining the separation and reaction steps inside a single column are advantageous as compared to traditional unit operations. The three considered processes are similar and at the same time very different. Therefore, their common modeling basis is discussed and their peculiarities are illustrated with a number of industrially relevant case studies. The theoretical description is supported by the results of laboratory-, pilot-, and industrial-scale experimental investigations. Both steady-state and dynamic issues are treated in addition, the design of column internals is addressed. 

Noeres C, Kenig EY, Gorak A. Modelling of reactive separation processes reactive absorption and reactive distillation. Chem Eng Process 2003 42 157-178. 

In the process reactive mixture is heated approximately to the boiling point of benzene (76-83 °C) there is a surplus of benzene for chlorination. At this temperature some of the chlorobenzene formed evaporates. The evaporation uses a lot of heat released during the reaction the rest is intensively withdrawn, and chlorinators, which work when the reactive mixture is boiling, are hightly efficient. The process is catalysed by iron chloride in the amount of 0.01-0.015% (mass) of benzene. To avoid the formation of polychlorides, chlorination is stopped when 50-68% of benzene remain unchanged. In this case polychlorides account for not more than 3.5-4.5% of the chlorobenzene amount. 

Fig. 4.1. Flash cascades [13] and batch processes (reactive condenser/reactive reboiler, [14]) being used to predict the top and bottom products of a countercurrent reactive distillation column.

In the field of integrated processes, reactive separations are prominently present due to the high degree of synergy to be achieved in many processes [1, 2]. Reactive separations can have positive effects on the conversion, as well as on the selectivity in a process. 

For a number of processes, reactive distillation is not possible, as some of the reactants are destroyed or degraded in side reactions by heating them up to boiling temperature. Examples of such processes are the Knoevenagel-condensation of aldehydes or ketones with components of high CH-acidity, the production of enam-ines or carbonic acid amides, or the esterification of fatty acids with fatty alcohols to fatty esters [7]. 

Process Reactive MF magnetron sputtering. Sinusoidal plasma excitation (40 kHz, Advanced Energy PEII). Static deposition. Boxcoater Pfeiffer PLS 580. Process operation in the metallic mode of the discharge. ... 

Several new catalytic asymmetric protonations of metal enolates under basic conditions have been published to date. In those processes, reactive metal enolates such as lithium enolates are usually protonated by a catalytic amount of chiral proton source and a stoichiometric amount of achiral proton source. Vedejs et al. reported a catalytic enantioselective protonation of amide enolates [35]. For example, when lithium enolate 43, generated from racemic amide 42 and s-BuLi, was treated with 0.1 equivalents of chiral aniline 31 followed by slow addition of 2 equivalents of ferf-butyl phenylacetate, (K)-enriched amide 42 was obtained with 94% ee (Scheme 2). In this reaction, various achiral acids were... 

The success of RIM has spurred interest in other means of reactive processing. Reactive extrusion and reactive blending are two related processes with interesting potential. Reactive extrusion refers to processes in which... 

Figure 6. Highly schematized depiction of the orthogonal influences of coal rank and coal type on coal grade (economic value) as reflected simply by the yield of liquids in a coal conversion (liquefaction) process (( ) reactive ingredients are vitrinite and exinite in higher rank coals, vitrinite and exinite give low yields)...

Nitrogen gas is used as an inert atmosphere for storing and processing reactive substances. 

Table of Examples, Classification Process, Reactivity Table... 

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