Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Nature of the hydrocarbon

The hydrocarbons are in general only slightly soluble in water. The solubility depends especially on the chemical nature of the hydrocarbons. [Pg.168]

More precisely, the rate of ozone formation depends closely on the chemical nature of the hydrocarbons present in the atmosphere. A reactivity scale has been proposed by Lowi and Carter (1990) and is largely utilized today in ozone prediction models. Thus the values indicated in Table 5.26 express the potential ozone formation as O3 formed per gram of organic material initially present. The most reactive compounds are light olefins, cycloparaffins, substituted aromatic hydrocarbons notably the xylenes, formaldehyde and acetaldehyde. Inversely, normal or substituted paraffins. [Pg.261]

Ba.se Catalyzed. Depending on the nature of the hydrocarbon groups attached to the carbonyl, ketones can either undergo self-condensation, or condense with other activated reagents, in the presence of base. Name reactions which describe these conditions include the aldol reaction, the Darzens-Claisen condensation, the Claisen-Schmidt condensation, and the Michael reaction. [Pg.487]

The hydrophilic nature of the carboxyl group balanced against the hydrophobic nature of the hydrocarbon chain allows long-chain fatty acids to form monomolecular films at aqueous Hquid-gas, Hquid—Hquid, or Hquid—soHd interfaces (18). [Pg.83]

Chlorination of Hydrocarbons or Chlorinated Hydrocarbons. Chlorination at pyrolytic temperatures is often referred to as chlorinolysis because it involves a simultaneous breakdown of the organics and chlorination of the molecular fragments. A number of processes have been described for the production of carbon tetrachloride by the chlorinolysis of various hydrocarbon or chlorinated hydrocarbon waste streams (22—24), but most hterature reports the use of methane as the primary feed. The quantity of carbon tetrachloride produced depends somewhat on the nature of the hydrocarbon starting material but more on the conditions of chlorination. The principal by-product is perchloroethylene with small amounts of hexachloroethane, hexachlorobutadiene, and hexachloroben2ene. In the Hbls process, a 5 1 mixture by volume of chlorine and methane reacts at 650°C the temperature is maintained by control of the gas flow rate. A heat exchanger cools the exit gas to 450°C, and more methane is added to the gas stream in a second reactor. The use of a fluidi2ed-bed-type reactor is known (25,26). Carbon can be chlorinated to carbon tetrachloride in a fluidi2ed bed (27). [Pg.531]

Fig. 27. Tack of polychloroprene-hydrocarbon resin blends (33 wt% resin content) as a function of the nature of the hydrocarbon resin. Tack was obtained as the immediate T-peel strength of joints produced with 0.6 mm thick styrene-butadiene rubber strips placed in contact without application of pressure. Peeling rate = 10 cm/min. Fig. 27. Tack of polychloroprene-hydrocarbon resin blends (33 wt% resin content) as a function of the nature of the hydrocarbon resin. Tack was obtained as the immediate T-peel strength of joints produced with 0.6 mm thick styrene-butadiene rubber strips placed in contact without application of pressure. Peeling rate = 10 cm/min.
The above considerations indicate the complex nature of the hydrocarbons known as caryophyllene. For practical purposes, however, the compounds indicated are obtained of practically definite melting-points, and, in spite of the complicated isomerism existing amongst most of them, are useful for identification of the sesquiterpene or mixture of sesquiterpenes, occurring naturally and known as caryophyllene . [Pg.88]

Give the probable hydrocarbon/water contact. Give the probable nature of the hydrocarbons and the gas/oil contact. [Pg.991]

The amount of energy required to carry out this process depends on the nature of the hydrocarbon it is the highest for saturated hydrocarbons (alkanes, cycloalkanes) and low for unsaturated and aromatic hydrocarbons (in fact, decomposition of acetylene and benzene are exothermic reactions). Methane is one of the most thermally stable organic molecules. [Pg.72]

An important question remains to be answered although the phenomenological P value appears to be fairly insensitive to the nature of the hydrocarbon bridge, does it necessarily follow that Pei, for the distance dependence of the electronic coupling, Vd, should likewise display a similar insensitivity Extracting Vd values, and hence 3d, from experimental ET rate data is presently fraught with difficulties and uncertainties. An alternative approach to this problem is to calculate the couplings. A par-... [Pg.277]

Methano[10]annulene represents a Hiickel-type aromatie(4w. + 2)jr-system and is reminiscent of benzene or napthhalene in both its physical and chemical properties.14 The aromatic nature of the hydrocarbon is... [Pg.80]

Lipophilicity. The gross lipophilicity of the ligand and of its complexes plays a very important role whenever substances soluble in organic media of low polarity are needed. This is the case in studies of anion activation and of cation transport through lipid membranes, where salts have to be dissolved in organic phases. The lipophilic character may be controlled via the nature of the hydrocarbon residues forming the ligand framework or attached to it. [Pg.20]

Figure 11. Increasing the PIT value by altering the emulsifier hydrophilic group (A-C) or nature of the hydrocarbon (B-D) give changes expected from the PIT concept (cf. Figure 9)... Figure 11. Increasing the PIT value by altering the emulsifier hydrophilic group (A-C) or nature of the hydrocarbon (B-D) give changes expected from the PIT concept (cf. Figure 9)...
An examination of the time - resolved spectra can be made, which provides additional details about the temperature - dependent changes in the nature of the hydrocarbon - bath interface during the detergency process. [Pg.260]

Thus clearly, the sulfided state of the palladium surface depends deeply on the nature of hydrocarbon in competition of adsorption. In conclusion, on a working catalyst (in hydro-dehydro reactions), the state of a sulfided surface depends on (1) the nature of the sulfur compounds, (2) the nature of the hydrocarbons, and (3) the nature of the metallic phase. [Pg.294]

In hydrogenation conditions the effect of sulfur adsorption is the result of interactions between the metal, the hydrocarbon, and the sulfur-containing compound. As a consequence, for a given metal, the sulfur coverage, and its effect on the activity and selectivity of the unpoisoned metallic surface area, will be defined by the nature of the hydrocarbon. [Pg.315]

From these extensive studies, we may conclude that the distance dependence of ET rates, mediated by a superexchange mechanism involving saturated hydrocarbon bridges, is largely independent of the nature of the hydrocarbon and has an average /3 value of 0.99 0.2 bond-1. [Pg.39]

In Fig. 2, the weight ratio mx/m2 of hydrocarbon to water is plotted as a function of the concentration of surfactant in the continuous phase (in weight percent) when sodium dodecyl sulfate (SDS) is employed as emulsifier. The above ratio is calculated for the point at which a small amount of hydrocarbon remains as a distinct phase. The ratio mjm2 depends upon the nature of the hydrocarbon employed and increases with the surfactant concentration, more rapidly at lower concentrations. A similar behavior was observed for a non-ionic surfactant, Triton X-100 (Fig. 3), but the values of mllm2 are smaller in this case than in Fig. 2. This happens because the electrostatic repulsion responsible for the stability of the concentrated emulsion containing SDS is stronger than the steric repulsion involved in the stability of the emulsion containing Triton X-100. [Pg.5]

Partial oxidation has practically no restrictions regarding the nature of the hydrocarbon and the sulfur content. Natural gas, refinery gases, LPG, naphtha, heavy fuel, vacuum residue, visbreaker oil, asphalt, and tar can be used as feedstock. As the investment costs for partial oxidation are higher than for steam reforming, mainly because of the cyrogenic air separation, it is usually not a choice for the lighter hydrocarbons, but heavy feedstocks from fuel oil to asphalt, when favorably priced, can be a competitive option for various locations and circumstances. In some special cases, where the primary reformer is a bottleneck for a capacity increase, a small parallel partial oxidation unit based on natural gas could be installed, if a surplus of... [Pg.101]


See other pages where Nature of the hydrocarbon is mentioned: [Pg.264]    [Pg.1197]    [Pg.79]    [Pg.277]    [Pg.215]    [Pg.4]    [Pg.139]    [Pg.53]    [Pg.47]    [Pg.84]    [Pg.189]    [Pg.1100]    [Pg.61]    [Pg.111]    [Pg.437]    [Pg.112]    [Pg.276]    [Pg.136]    [Pg.330]    [Pg.290]    [Pg.243]    [Pg.112]    [Pg.116]    [Pg.88]    [Pg.90]    [Pg.28]    [Pg.36]    [Pg.10]    [Pg.1197]   
See also in sourсe #XX -- [ Pg.276 ]

See also in sourсe #XX -- [ Pg.276 ]




SEARCH



Sources of natural hydrocarbons in the marine environment

Sources of natural hydrocarbons in the marine environment some processes controlling their distribution

© 2024 chempedia.info