Thermal yield

Bond- or Mode-selective Laser Chemistry. Suppose we wish to break a specific bond in a molecule or cause a molecule to rearrange in a specific way, and the desired transformation is not the one which will occur if the molecule is simply heated (i.e., it is not the weakest coordinate in the molecule). Can we, by selectively exciting with a laser the bond or motion in question, cause the desired transformation to occur in greater than thermal yield ... 

By substractlng the thermal yield from the overall yield, the corrected yield was calculated. Beyond a certain mass of MMA or St, the yields became to be independent of the mass of the monomer. This is explained by the following consideration the first step of the polymerization is the incorporation of monomer into the hydrophobic areas. When a sufficient mass of the monomer is added, the areas may be saturated with the monomer. Thus, the excess of the monomer becomes useless. 

Thermal Yield Tensile Conductivity Strength Modulus Hardness OV/m°C) (N/mm2) (N/mm2) (DPN)... 

The anhydro-5-hydroxy-l,3,2-oxathiazolylium hydroxide system (83) and DMAD thermally yielded an intermediate 1 1 cycloadduct (84) which lost C02 forming dimethyl 2-phenylisothiazole-3,4-dicarboxylate (85) (72CB196). Irradiation of (83) in neat DMAD formed the valence tautomer (82) which lost C02 to give the nitrile sulfide dipole (81) captured by DMAD to form dimethyl 3-phenylisothiazole-4,5-dicarboxylate (80) (75JA6197) (see also CHEC 4.17). 

Thermal yields from Crouch (1977). Weapons yields from UNSCEAR (1962). 

Figure 2. Naphthalene yield as a function of time in the presence of various additives. The dotted line is the sum of the thermal yield curve and the calculated amount of naphthalene obtained by the full reduction of 50 mg of pyrite...

Now the solvent (e.g., cyclohexanone) will yield 14,000 BTUs/lb upon incineration, so that the 68.4 gallons of solvent burnt per hour have a thermal yield of... 

Here we report about 2+2 thermocycloreversions of 1-o-tolyl-l-methyl-1-silacycIobutane (la), 1-m-tolyl-l-methyl-1-silacyclobutane (lb), and 1-p-tolyl-l-methyl-1-silacyclobutane (Ic) resulting in ethylene and corresponding transient 1-o-tolyl-l-methylsilene (2a), l-/w-tolyl-l-methylsilene (2b), and 1-p-tolyl-l-methylsilene (2c) formations, respectively. Silenes 2a-c rearrange thermally yielding appropriate 3,4-benzo-1 -silacyclobut-3-enes 3a, 3b, 3b, and 3c (Scheme 2). 

The tetrakis-(l-amino-siloxane) condenses thermally, yielding a spirocyclic six-membered ring... 

Countercurrent operation of shaft and rotary kiln furnaces leads to extensive heat transfer between feedstock and outgoing products. The sensible heat of the products remains within the system which enhances its thermal yield. Cocurrent operation shows none of these advantages yet it is a simple and efficient method to avoid tar problems. Indeed the tar is extensively cracked while moving through the hearth zone. Also the problem of wastewater is somewhat simplified. Crosscurrent operation is only seldom used. 

A second method for the synthesis of phenoxarsines starts from o-phenoxyanilines (60). The o-phenoxyarsonic acids (61), accessible from (60) via the Bart reaction, are reduced to give the dichloroarsines, which then cyclize thermally yielding (59) (Scheme 9) <25JCS544,34JCS1170,36JCS1236, 39JCS1720>. 

In the heat of solubility method for adhesion determination, the film material is chemically dissolved from the substrate, e.g. by an exothermic reaction. The total energy thus converted consists of the energy released by the dissolving of the pure film material less the energy required to break the bonds between film and substrate. To enhance the contribution from the adhesion the ratio of the number of molecules on the film/substrate interface should be as high as possible in relation to the total number of molecules in the film. The thermal yield of the reaction is determined with a microcalorimeter, although tests with coated metal films on NaCl substrates have shown the sensitivity of such equipment to be, as yet, insufficient for exact measurements [74,75]. 

The possibility of valence isomerization also affects the reactions of the oxepins [5]. For instance, cycloadditions involve the benzene oxide, as shown by the Diels-Alder reaction with activated al-kynes, and give the epoxybicyclo[2.2.2]octatriene 9 or, in the presence of singlet oxygen, afford the peroxide 10. The latter isomerizes thermally yielding the ra .s-benzene trioxide 11 ... 

An overall reduction in heat production may be obtained by incorporating compounds in the polymer compounds which decompose endothermically, i.e., make a negative contribution to the overall thermal yield. It is, after all, the heat of combustion of the plastics, which sustains the propagation of the flame by bringing about further pyrolysis adjacent to the combustion zone. 

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