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Route characteristics

This chapter deals with the properties of the excited states of 1,2-diary lethylenes in general, with the effects caused by specific variation of reaction conditions on photochemical cis trans isomerization in condensed phase, and with the reaction mechanisms. In particular, the influence of substitution on the properties of excited states involved in cis trans isomerization in solution is examined. Besides various substituted stilbenes (which have been most extensively studied), styrylpyridines (StPs, azastilbenes) including some of their positively charged derivatives (quaternary stilbazolium salts), dipyridylethylenes (DPEs), styrylnaphthalenes (StNs), their pyridine analogues (NPEs), and some related compounds, such as dinaphthylethylenes (DNEs), are surveyed. Results on photochemical cis ttrans isomerization of stilbenes and other 1,2-diarylethylenes under direct (Section II) and sensitized (Section III) irradiation conditions are summarized, as well as their photophysical excited singlet and triplet state properties (Section IV) and some selected side reactions (Section V). The mechanistic section (Section VI) describes several photochemical isomerization routes. Characteristic photophysical and photochemical aspects of specific classes of substituted stilbenes are discussed and mechanistic schemes are critically examined with reference to their experimental basis. [Pg.4]

The site-level health and safety manager was given notice from corporate for the need to conduct the qualitative risk analysis of the plant s hazardous material transportation operations. The safety manager was provided with a questiotmaire regarding all chemicals of concern, shipping quantities, modes of transit, and the route characteristics (similar to the checklist found in Table 4.2). This information was transmitted back to corporate for analysis, which included a corporate-level comparison to the other XYZ Chemical facihties risk results. Based on the information collected at the site level, the following was determined and reviewed by corporate for this facility ... [Pg.56]

Route characteristics Include the crossing of environmental areas, passing of potential infrastructure, and distance location and density of people along the route. [Pg.61]

Comparison of modes of transportation Quantity, or package sizes, in transit Chemical-specific hazards Route characteristics Transportation package design... [Pg.79]

Mineralocorticoids foUow a mechanistic route similar to that of glucocorticoids, though differing in the proteins expressed. The activated MR-DNA complex promotes the expression of aldosterone-induced proteins (AIPs), which then act to increase conductance of the luminal membrane and concurrently increase pump activity of the basolateral membrane. These actions result from a number of AlP-influenced cellular characteristics,... [Pg.98]

Esters. Most acryhc acid is used in the form of its methyl, ethyl, and butyl esters. Specialty monomeric esters with a hydroxyl, amino, or other functional group are used to provide adhesion, latent cross-linking capabihty, or different solubihty characteristics. The principal routes to esters are direct esterification with alcohols in the presence of a strong acid catalyst such as sulfuric acid, a soluble sulfonic acid, or sulfonic acid resins addition to alkylene oxides to give hydroxyalkyl acryhc esters and addition to the double bond of olefins in the presence of strong acid catalyst (19,20) to give ethyl or secondary alkyl acrylates. [Pg.150]

Acetophenone. Acetophenone [98-86-2] (methyl phenyl ketone) is a colorless Hquid that forms laminar crystals at low temperature (mp 20°C). It has a characteristic sweet orange blossom odor, and is soluble in alcohols and ethers. It is found in nature in oil of casatoreum, obtained from beavers oil of labdanum, recovered from plants and in buds of balsam poplar. It can be prepared by the Friedel-Crafts reaction (qv) of acetyl chloride with benzene in the presence of aluminum chloride however, this route is of Htde commercial significance. [Pg.501]

Skin. The skin may become contaminated accidentally or, in some cases, materials may be deHberately appHed. Skin is a principal route of exposure in the industrial environment. Local effects that are produced include acute or chronic inflammation, allergic reactions, and neoplasia. The skin may also act as a significant route for the absorption of systemicaHy toxic materials. Eactors influencing the amount of material absorbed include the site of contamination, integrity of the skin, temperature, formulation of the material, and physicochemical characteristics, including charge, molecular weight, and hydrophilic and lipophilic characteristics. Determinants of percutaneous absorption and toxicity have been reviewed (32—35,42,43,46—49). [Pg.229]

Ha2ard is the likelihood that the known toxicity of a material will be exhibited under specific conditions of use. It follows that the toxicity of a material, ie, its potential to produce injury, is but one of many considerations to be taken into account in assessment procedures with respect to defining ha2ard. The following are equally important factors that need to be considered physicochemical properties of the material use pattern of the material and characteristics of the environment where the material is handled source of exposure, normal and accidental control measures used to regulate exposure the duration, magnitude, and frequency of exposure route of exposure and physical nature of exposure conditions, eg, gas, aerosol, or Hquid population exposed and variabiUty in exposure conditions and experience with exposed human populations. [Pg.238]

At 225—275°C, bromination of the vapor yields bromochloromethanes CCl Br, CCl2Br2, and CClBr. Chloroform reacts with aluminum bromide to form bromoform, CHBr. Chloroform cannot be direcdy fluorinated with elementary flourine fluoroform, CHF, is produced from chloroform by reaction with hydrogen fluoride in the presence of a metallic fluoride catalyst (8). It is also a coproduct of monochlorodifluoromethane from the HF—CHCl reaction over antimony chlorofluoride. Iodine gives a characteristic purple solution in chloroform but does not react even at the boiling point. Iodoform, CHI, may be produced from chloroform by reaction with ethyl iodide in the presence of aluminum chloride however, this is not the route normally used for its preparation. [Pg.524]

The resulting motion of the beam is detected by the pneumatic nozzle amphfier, which, by proper sizing of the nozzle and fixed orifice diameters, causes the pressure internal to the nozzle to rise and fall with vertical beam motion. The internal nozzle pressure is routed to the pneumatic relay. The relay, which is constructed like the booster relay described in the Valve Control Devices subsection, has a direct hnear input-to-output pressure characteristic. The output of the relay is the controller s output and is piped away to the final control element. [Pg.776]

Haul distance Although minimum haul distances are desirable, other factors must also he considered. These include collection-route location, types of wastes to he hauled, local traffic patterns, and characteristics of the routes to and from the disposal site (condition of the routes, traffic patterns, and access conditions). [Pg.2253]

Accepts information on the major safety characteristics of routes Routes may create problems because of width access traffic patterns and jurisdictions. [Pg.272]

Based on characteristics of routes available, selects the least dangerous route. [Pg.276]

The circumstances under which water becomes contaminated are as varied as the ways water is taken internally. It is then conceivable that almost any virus could be transmitted through the water route. The increased use of water for recreational purposes increases the incidence of human contact with bodies of water and, consequently, with waterborne viruses and bacteria. The major waterborne viruses among pathogens, and the most likely candidates for water transmission, are the picornaviruses (from pico, meaning very small, and RNA, referring to the presence of nucleic acid). The characteristics of picornaviruses are shown in Table 1. Among the picornaviruses are the enteroviruses (polioviruses, coxsackieviruses. [Pg.447]

Conventional Flare System - The majority of pressure relief valve discharges which must be routed to a closed system are manifolded into a conventional blowdown drum and flare system. The blowdown drum serves to separate liquid and vapor so that the vapor portion can be safely flared, and the separated liquid is pumped to appropriate disposal facilities. The blowdown drum may be of the condensible or noncondensible type, according to the characteristics of the streams entering the system. Selection criteria, as well as the design basis for each type of blowdown drum, are detailed later in this volume. The design of flares, including seal drums and other means of flashback protection, is described later. [Pg.207]

Skin is also important as an occupational exposure route. Lipid-soluble solvents often penetrate the skin, especially as a liquid. Not only solvents, but also many pesticides are, in fact, preferentially absorbed into the body through the skin. The ease of penetration depends on the molecular size of the compound, and the characteristics of the skin, in addition to the lipid solubility and polarity of the compounds. Absorption of chemicals is especially effective in such areas of the skin as the face and scrotum. Even though solid materials do not usually readily penetrate the skin, there are exceptions (e.g., benzo(Lt)pyrene and chlorophenols) to this rule. [Pg.258]

Theoretical and measured strengths and stiffnesses of three-layer cross-ply laminates with cross-ply ratios ranging from. 2 to 4 are shown in Figure 4-44. The scatter in the data is partially due to the difficulty of making good tensile specimens the characteristic dog-bone shape is formed by routing that often damages the 90° layer. [Pg.254]

The very slow onset of action and side effects which follow from the anticholinergic side effects characteristic of the tricyclic antidepressants has led to a continuing effort to find replacements from other structural classes which might thus be devoid of this defect. A series of alkoxy phenylpropylamines has been investigated extensively in this search for non-tricyclic antidepressants. The most recent analogue, tomoxetine (69), is accessible by the same route [15] used to prepare the earlier analogue, nisoxetine, in which methoxyl replaces the ortho methyl group. [Pg.30]

Theories of the oxidation of tantalum in the presence of suboxide have been developed by Stringer. By means of single-crystal studies he has been able to show that a rate anisotropy stems from the orientation of the suboxide which is precipitated in the form of thin plates. Their influence on the oxidation rate is least when they lie parallel to the metal interface, since the stresses set up by their oxidation to the pentoxide are most easily accommodated. By contrast, when the plates are at 45° to the surface, complex stresses are established which create characteristic chevron markings and cracks in the oxide. The cracks in this case follow lines of pores generated by oxidation of the plates. This behaviour is also found with niobium, but surprisingly, these pores are not formed when Ta-Nb alloys are oxidised, and the rate anisotropy disappears. However, the rate remains linear it seems that this is another case in which molecular oxygen travels by sub-microscopic routes. [Pg.285]


See other pages where Route characteristics is mentioned: [Pg.41]    [Pg.641]    [Pg.29]    [Pg.50]    [Pg.268]    [Pg.200]    [Pg.41]    [Pg.641]    [Pg.29]    [Pg.50]    [Pg.268]    [Pg.200]    [Pg.1103]    [Pg.315]    [Pg.196]    [Pg.125]    [Pg.237]    [Pg.403]    [Pg.346]    [Pg.326]    [Pg.389]    [Pg.525]    [Pg.197]    [Pg.540]    [Pg.25]    [Pg.66]    [Pg.262]    [Pg.330]    [Pg.369]    [Pg.382]    [Pg.325]    [Pg.223]    [Pg.384]    [Pg.13]    [Pg.66]    [Pg.436]   


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