Styrene, reaction

ETHYL 4-METHYL-E-4,8-NON-ADIENOATE, 53, 116 Styrene, reaction with carbe-thoxycarbene, 50, 94 Suberoyl chloride, 54, 88 SUBSTITUTION OF ARYL HALIDES WITH COPPER(I) ACETYLIDES ... 

Several reactions of halogen-substituted carbon-centered radicals with silanes have been studied, but limited kinetic information is available for reactions of halogen-substituted radicals with tin hydrides. A rate constant for reaction of the perfluorooctyl radical with Bu3SnH was determined by competition against addition of this radical to styrenes, reactions that were calibrated directly by LFP methods.93 At ambient temperature, the n-C8F17 radical reacts with tin hydride two orders of magnitude faster than does an alkyl radical, consistent with the electron-deficient nature of the perflu-oroalkyl radical and the electron-rich character of the tin hydride. Similar behavior was noted previously for reactions of silanes with perhaloalkyl radicals. 

In contrast to 4-alkyl-5-sulfonylimino-A -l,2,3,4-thiatriazolines (58) (Section 4.19.5.1.2), 4-alkyl-5-alkylimino-A -l,2,3,4-thiatriazolines (50) react with immediate nitrogen evolution when added to electron-rich alkenes or to heterocumulenes such as enamines, carbodiimides, isocyanates, isothiocyanates, or styrene. Reaction kinetics for certain of this type of system show that they undergo bimolecular processes as described below. 

This has been studied much less frequently and appears to be a rather more complex reaction. The first results obtained, for the butyl-lithium, styrene reaction in benzene have already been described. In a similar way the addition of butyllithium to 1,1-diphenylethylene shows identical kinetic behaviour in benzene (26). Even the proton extraction reaction with fluorene shows the typical one-sixth order in butyllithium (27). It appears therefore that in benzene solution at least, lithium alkyls react via a small equilibrium concentration of unassociated alkyl. This will of course not be true for reactions with polar molecules for reasons which will be apparent later. No definite information can be obtained on the dissociation process. It is possible that the hexamer dissociates completely on removal of one molecule or that a whole series of penta-mers, tetramers etc. exist in equilibrium. As long as equilibrium is maintained, the hexamer is the major species present and only monomeric butyllithium is reactive, the reaction order will be one-sixth. A plausible... 

The use of styrene to modify sulfur melts and thus to improve the binder properties was unsuccessful. When producing sulfur binder modified with styrene, reaction times of at least 1.5 hr at 140°C were used, since by then the viscosity maximum had been passed and a constant viscosity value had been reached. Sulfur melts plasticized by... 

In Fig. 6 carbon dioxide reactions are categorized by industrially important products. Hydrogenation reactions produce alcohols, hydrocarbon synthesis reactions produce paraffins and olefins, and amine synthesis produces methyl and higher-order amines. Hydrolysis reactions can produce alcohols and organic acids. Carbon dioxide serves as an oxygen source in the ethyl benzene to styrene reaction. It can be used in dehydrogenation and reforming reactions. 

Sodium amalgam, 50, 50, 51 Sodium azide, 50,107 Sodium formate, reaction with acetyl chloride, 50, 1 Sommelet reaction, 50, 71 Styrene, reaction with carbethoxy-carbene, 50,94... 

Examples 13-3 to 13-5 illustrate the simplified design method for different cases. The first is for the endothermic styrene reaction, where the temperature decreases continually with catalyst-bed depth. Example 13-4 is for an exothermic reaction carried out under conditions where radial temperature gradients are not large. Example 13-5 is also for an exothermic case, but here the gradients are severe, and the simplified solution is not satisfactory. 

Figure 2 investigation of activity and Pd leaching as a function of time Heck coupling of bromobenzene with styrene reaction conditions bromobenzene (200 mmol), styrene (300 mmol), sodium acetate (240 mmol), 1.0 mol% Pd, catalyst 3W, DM Ac (200 mL) T = 140 °C styrene was added last after catalyst, solvent, and bromo benzene had reached 140 °C. 

Figure 1 A Model of the surface crystallography of iron oxide (Fe20s) as determined from LEED analysis of a thin fdm grown at Imbar oxygen pressure. The numbers indicate the positional changes of the atomic layers in percent with respect to the position in the bulk structure. B LEED image of a film before and after use as catalyst of dehydrogenation of ethylbenzene (EB) to styrene reaction temperature 873 K, reactant pressure Ibar, composition steam to EB 10 1, LHSV 0.5 h. The unit cell reflections for (001) Fe20s are indicated by circles. C Evolution of the conversion to styrene as function of time on stream under the conditions given in (B)...

The reaction rate constant for the styrene-Os reaction is larger by around 3-5 orders of magnitude than those for the other 5 aromatics at 300K [169]. However, this high conversion of styrene even at low SIE values does not mean a higher decomposition performance, because of the poor carbon balance (see below). These results indicate that intermediates from the ozone-styrene reaction were deposited on the surface of the catalyst. Formic acid, which was the common intermediate from the aromatic compounds, was decomposed more easily than the aromatic compounds. The overall kinetics can be described as a function of SIE. 

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