Conversion thermal

Claisen rearrangement (Section 24 13) Thermal conversion of an allyl phenyl ether to an o allyl phenol The rearrange ment proceeds via a cyclohexadienone intermediate... 

U.S. capacity for producing biofuels manufactured by biological or thermal conversion of biomass must be dramatically increased to approach the potential contributions based on biomass availabiUty. For example, an incremental EJ per year of methane requires about 210 times the biological methane production capacity that now exists, and an incremental EJ per year of fuel ethanol requires about 14 times existing ethanol fermentation plant capacity. 

Chemical Processes. Biological—biochemical and thermal conversion processes are chemical processes, too, but a few specific chemical processes are mentioned separately because they are directed more to conventional chemical processing and production. These processes have been grouped together as chemical processes. 

J. L. Jones and S. B. Radding, eds.. Thermal Conversion of Solid Wastes and Biomass, ACS Symposium Series 130, American Chemical Society, Washington,... 

Binders. Paper-coating biaders are either polymers derived from aatural sources or syathetic polymers. The largest volume, aaturally derived biader is starch (qv) (99). Starch is provided ia derivatized form or unmodified form pead com starch is used predomiaanfly for the latter. Unmodified starch is solubilized by thermal conversion or enzyme conversion. The most common derivatized products are acetylated [9045-28-7] oxidized, and hydroxyethylated starches. 

The main limitation to thermal conversion is that the products can be unstable. Thermal cracking at low pressure gives olefins, particularly in the naphtha fraction such olefins yield an unstable product that tends to form gum as well as heavier products that form sediments (5). 

H. Alter and J. J. Duim, Jr., Solid Waste Conversion to Energy Current European and U.S. Practices, Marcel Dekker, Inc., New York, 1980, Chapt. 5 H. Alter andj. A. CampbeU, in J. L. Jones and S. B. Radding, eds.. The Preparation and Properties ofDensified Refuse-Derived Fuel, Thermal Conversion of Solid Wastes andBiomass, American Chemical Society, Washington, D.C., 1980, pp. 127—142. 

More than 95% of current carbon fiber production for advanced composite appHcations is based on the thermal conversion of polyacrylonitrile (PAN) or pitch precursors to carbon or graphite fibers. Generally, the conversion of PAN or pitch precursor to carbon fiber involves similar process steps fiber formation, ie, spinning, stabilization to thermoset the fiber, carbonization—graphitization, surface treatment, and sizing. Schematic process flow diagrams are shown in Eigure 4. However, specific process details differ. 

The nature of the sulfonium stmcture affects the yield and quaUty of the resulting PPV, and it has been found that use of cycHc sulfonium stmctures (12) is preferable (106). With cycHc sulfonium polyelectrolytes, more efficient elimination of sulfur and the counterion occurs during thermal conversion, so fewer sp defects are present in the final PPV. 

An intramolecular [4 + 2] cycloaddition is represented by a thermal conversion of allylphenoxy- and allyloxyphenoxy-pyridazines into xanthenes (80CPB198). 

The thermal conversion of 1-substituted 5-aminotetrazole (423) into a 5-substituted aminotetrazole (424) can be rationalized by a similar 1,5-dipolar cyclization. 

Thermal conversion of diazirines to linear diazo compounds was postulated occasionally and proved by indirect methods. The existence of a diazo compound isomeric to diazirine (197) was proved spectroscopically on short thermolysis in DMSO (76JA6416). An intermediate diazoalkane was trapped by reaction with acetic acid, yielding the ester (198) (77JCS(P2)1214). 

To determine emission data, as well as the effect that fuel changes would produce, it is necessary to use the appropriate thermal conversion factor from one fuel to another. Table 6-5 lists these factors for fuels in common use. 

Suprafacial 1,3-shifts with inversion of configuration at the migrating carbon have also been observed in the thermal conversion of bicyclo[2.1.1]hexenes to bicyclo[3.1.0]-hexenes. ... 

Since multiple electrical and optical functionality must be combined in the fabrication of an OLED, many workers have turned to the techniques of molecular self-assembly in order to optimize the microstructure of the materials used. In turn, such approaches necessitate the incorporation of additional chemical functionality into the molecules. For example, the successive dipping of a substrate into solutions of polyanion and polycation leads to the deposition of poly-ionic bilayers [59, 60]. Since the precursor form of PPV is cationic, this is a very appealing way to tailor its properties. Anionic polymers that have been studied include sulfonatcd polystyrene [59] and sulfonatcd polyanilinc 159, 60]. Thermal conversion of the precursor PPV then results in an electroluminescent blended polymer film. 

Oxazepines are readily decomposed by heat and light and by acids and bases.8 Some of these reactions proceed by hydrolytic opening of the oxazepine ring, as in the formation of 1-benzoylpyrrole (1) from 2-phenyl-l,3-oxazepine and cold dilute hydrochloric acid,12 while others involve valence-tautomeric oxazanorcaradienes, as in the thermal conversion of 2-phenyl-l,3-oxazcpine into 2-phenylpyridin-3-ol (2).12... 

The most reasonable mechanism for this transformation, in accord with that suggested by van Tamelen et al. for the dilute acid photolysis, is initial photoisomerization to 2 followed in this case by thermal conversion of the Dewar tropylium ion to 7. The isomerization of 2 to 7 has been reported to be very rapid at temperatures below —60°, and it has been shown, in addition that, in nucleophilic solvents, capture of 2 competes very efficiently with isomerization (Lustgarten et al., 1967). 

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