Three reactions

Example 2.1 Given that the objective is to manufacture vinyl chloride, there are at least three reaction paths which can be readily exploited. ... 

Example 2.2 Devise a process from the three reaction paths in Example 2.1 which uses ethylene and chlorine as raw materials and produces no byproducts other than water. Does the process look attractive economically ... 

If we add these three reactions to get the overall stoichiometry, we obtain... 

There are two independent coordinates that define the plane of a loop. If the loop is phase inverting, one of these coordinates must be phase inverting, the other, phase preserving. Out of the infinite number of possible candidates, a convenient choice are reaction coordinates (Section I). Any one of the three reaction coordinates connecting two of the anchors can be used for the... 

We have seen (Section I) that there are two types of loops that are phase inverting upon completing a round hip an i one and an ip one. A schematic representation of these loops is shown in Figure 10. The other two options, p and i p loops do not contain a conical intersection. Let us assume that A is the reactant, B the desired product, and C the third anchor. In an ip loop, any one of the three reaction may be the phase-inverting one, including the B C one. Thus, the A B reaction may be phase preserving, and still B may be attainable by a photochemical reaction. This is in apparent contradiction with predictions based on the Woodward-Hoffmann rules (see Section Vni). The different options are summarized in Figure 11. 

In order to further cla.ssify these reactions, a search for reactions that transform ATP to ADP was made, resulting in 139 reactions 139 of the above 304 reactions involve the breaking of a P-0 bond in ATP, emphasizing the central importance of this bond breaking as a source of energy, An additional three reactions involve the transformation of GTP to GDP. As many reactions transferring a phosphate group... 

Cyclic alkenes give different regioisomers depending on the reaction conditions owing to double bond isomerization caused by syii elimination of Pd—H species and its readdition. The following three reaction conditions were tested for the reaction of cycloheptene (35)[18,38] ... 

The most apparent chemical property of carboxylic acids their acidity has already been examined m earlier sections of this chapter Three reactions of carboxylic acids—con version to acyl chlorides reduction and esterification—have been encountered m pre vious chapters and are reviewed m Table 19 5 Acid catalyzed esterification of carboxylic acids IS one of the fundamental reactions of organic chemistry and this portion of the chapter begins with an examination of the mechanism by which it occurs Later m Sec tions 19 16 and 19 17 two new reactions of carboxylic acids that are of synthetic value will be described... 

This reaction can be separated into three reactions for which equilibrium constants are known—the solubility of AgCl, described by its Ksp... 

This reaction can be broken down into three reactions. The first of these reactions is the solubility of PbCb, described by its Kjp... 

There are three reactions used for the production of oxamide ... 

SiHcone mbber has a three-dimensional network stmcture caused by cross-linking of polydimethyl siloxane chains. Three reaction types are predominantiy employed for the formation of siHcone networks (155) peroxide-induced free-radical processes, hydrosdylation addition cure, and condensation cure. SiHcones have also been cross-linked using radiation to produce free radicals or to induce photoinitiated reactions. 

PO—SM Coproduction. The copioduction of propylene oxide and styrene (40—49) includes three reaction steps (/) oxidation of ethylbenzene to ethylbenzene hydroperoxide, (2) epoxidation of ethylbenzene hydroperoxide with propylene to form a-phenylethanol and propylene oxide, and (3) dehydration of a-phenylethanol to styrene. 

Bleaching and decolorization can occur by destroying one or more of the double bonds in the conjugated chain, by cleaving the conjugated chain, or by oxidation of one of the other moieties in the conjugated chain. The result of any one of the three reactions is an increase in the energy gap between the... 

Three reactions dominate ethylene oxide production ... 

Efforts have also been made to overcome compHcated processes. Methods to reduce the number of steps or to use new starting materials have been studied extensively. l-Amino-2-chloro-4-hydroxyanthraquinone (the intermediate for disperse red dyes) conventionally requires four steps from anthraquinone and four separation (filtration and drying) operations. In recent years an improved process has been proposed that involves three reactions and only two separation operations starting from chloroben2ene (Fig. 2). 

The reactivity sequence furan > tellurophene > selenophene > thiophene is thus the same for all three reactions and is in the reverse order of the aromaticities of the ring systems assessed by a number of different criteria. The relative rate for the trifluoroacetylation of pyrrole is 5.3 x lo . It is interesting to note that AT-methylpyrrole is approximately twice as reactive to trifluoroacetylation as pyrrole itself. The enhanced reactivity of pyrrole compared with the other monocyclic systems is also demonstrated by the relative rates of bromination of the 2-methoxycarbonyl derivatives, which gave the reactivity sequence pyrrole>furan > selenophene > thiophene, and by the rate data on the reaction of the iron tricarbonyl-complexed carbocation [C6H7Fe(CO)3] (35) with a further selection of heteroaromatic substrates (Scheme 5). The comparative rates of reaction from this substitution were 2-methylindole == AT-methylindole>indole > pyrrole > furan > thiophene (73CC540). 

Simultaneous reactions. The overall rate is the algebraic sum of the rates of the individual reactions. For example, take the three reactions ... 

Multiple Reactions When a substance participates in several reactions at the same time, its net rate of decomposition is the algebraic sum of its rates in the individual reactions. Identify the rates of the individual steps with subscripts, dC/dt)i, dC/di)9,. Take this case of three reactions,... 

Example 2 Analysis of Three Simultaneous Reactions Consider the three reactions... 

Although methanol from synthesis gas has been a large-scale industrial chemical for 70 years, the scientific basis of the manufacture apparently can stand some improvement, which was undertaken by Beenackers, Graaf, and Stamhiiis (in Gheremisinoff, ed., Handbook of Heat and Mass Transfer, vol. 3, Gulf, 1989, pp. 671—699). The process occurs at 50 to 100 atm with catalyst of oxides of Gii-Zn-Al and a feed stream of H2, GO, and GO2. Three reactions were taken for the process ... 

Various Langmiiir-Hinshelwood mechanisms were assumed. GO and GO2 were assumed to adsorb on one kind of active site, si, and H2 and H2O on another kind, s2. The H2 adsorbed with dissociation and all participants were assumed to be in adsorptive equilibrium. Some 48 possible controlling mechanisms were examined, each with 7 empirical constants. Variance analysis of the experimental data reduced the number to three possibilities. The rate equations of the three reactions are stated for the mechanisms finally adopted, with the constants correlated by the Arrhenius equation. 

Reaction (12-9) shows the photochemical dissodation of NO2. Reaction (12-10) shows the formation of ozone from the combination of O and molecular O2 where M is any third-body molecule (principally N2 and O2 in the atmosphere). Reaction (12-11) shows the oxidation of NO by O3 to form NO2 and molecular oxygen. These three reactions represent a cyclic pathway (Fig. 12-4) driven by photons represented by hv. Throughout the daytime period, the flux of solar radiation changes with the movement of the sun. However, over short time periods (—10 min) the flux may be considered constant, in which case the rate of reaction (12-9) may be expressed as... 

These three reactions fail to account for all the observed phenomena that occur in curing casein and therefore a number of alternative mechanisms no doubt also occur. 

The least desirable of the three reactions is (b) as this results in the formation of some chlorodihydro-base and adds to the complexity of the mixtiu"e of reaction products. 

Ludwig Claisen was a German chemist who worked during the last two decades of the nineteenth century and the first two decades of the twentieth. His name is associated with three reactions. The Claisen-Schmidt reaction was presented in Section 18.10, the Claisen condensation is discussed in this section, and the Claisen rearrangement will be introduced in Section 24.13. 

In all three reactions, MP2 theory overcompensates for electron correlation (as it often does). Of the methods used in the original study, only the MP3 level provides an adequate treatment of these reactions. Note, however, it is the special characteristics of isodesmic reactions that enables MP3 to do so well. 

Glyoxysomes Must Borrow Three Reactions from Mitochondria... 

Write a balanced equation for the synthesis of a glucose molecule from ribulose-l,5-bisphosphate and COg that involves the first three reactions of the Calvin cycle and subsequent conversion of the two glyceraldehyde-3-P molecules into glucose. 

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