Reaction illustration

The above situation led to the proposal by Rideal [202] of what has become an important alternative mechanism for surface reactions, illustrated by Eq. XVIII-33. Here, reaction takes place between chemisorbed atoms and a colliding or physical adsorbed molecule (see Ref. 203). 

Figure A3.14.2. Characteristic features of a clock reaction, illustrated for the Landolt reaction, showing (a) variation of product concentration witii induction period followed by sharp reaction event (b) variation of overall reaction rate witli course of reaction.

Discuss the factors which influence the redox potential of a half-reaction, illustrating your answer by as many examples as possible. 

These reactions illustrate the oxidising action of iodine. 

This reaction illustrates one of the methods by which R. Kuhn synthesised long polyene chains terminated at each end by phenyl groups. 

This reaction illustrates the conversion of the —COCH3 group into the —COOH group by means of a hypohalite ... 

When esterification is the objective water is removed from the reaction mixture to encourage ester formation When ester hydrolysis is the objective the reaction is carried out m the presence of a generous excess of water Both reactions illustrate the applica tion of Le Chatelier s principle (Section 6 10) to organic synthesis... 

The following series of reactions illustrates the manufacture of the principal Reppe acetylene chemicals. 

This reaction illustrates a stereoselective preparation of (Z)-vinylic cuprates, which are very useful synthetic intermediates. They react with a variety of electrophiles such as carbon dioxide, epoxides, aldehydes, allylic halides, alkyl halides, and acetylenic halides they undergo... 

If trimellitic anhydride is used instead of pyromellitic dianhydride in the reaction illustrated in Figure 18.35 then a polyamide-imide is formed (Figure 18.37). The Torlon materials produced by Amoco Chemicals are of this type. 

We will compute AH for the reaction illustrated at the start of this section, using the following procedure ... 

A first-order reaction plot I ho rate constant for a first-order reaction can be determined from the slope of a plot of ln[A] versus time. The reaction illustrated, at 67°C. 

For the aza-Diels-Alder reaction illustrated above, water works better than LP-DE as a reaction medium, providing the cycloadducts in good yield with outstanding stereocontrol. 

Quinoxalinecarboxylic acids undergo several useful reactions, illustrated in the following classified examples. 

For a number of applications curing at room temperature is desirable. This so-called cold cure is brought about by using a peroxy initiator in conjunction with some kind of activator substance. The peroxy compounds in these cases are substances such as methyl ethyl ketone peroxide and cyclohexanone peroxide, which as used in commercial systems tend not to be particularly pure, but instead are usually mixtures of peroxides and hydroperoxides corresponding in composition approximately to that of the respective nominal compounds. Activators are generally salts of metals capable of undergoing oxidation/reduction reactions very readily. A typical salt for this purpose is cobalt naphthenate, which undergoes the kind of reactions illustrated in Reactions 4.6 and 4.7. 

This reaction illustrates the striking difference in behavior between carboxylic esters on the one hand and aldehydes and ketones on the other. When a carbanion such as an enolate ion is added to the carbonyl group of an aldehyde or ketone (16-41), the H or R is not lost, since these groups are much poorer leaving groups than OR. Instead the intermediate similar to 146 adds a proton at the oxygen to give a hydroxy compound. 

The following reactions illustrate the aluminothermic and magnesiothermic processes ... 

Introduce concept of displacement reaction illustrating with the full balanced chemical equation for the reaction between zinc and aqueous coppeifll) sulphate. 

Scheme 5.16. In some instances, e.g. the aza-Diels-Alder reaction illustrated, Lewis acid catalysts are additionally required but use of ionic liquids greatly enhanees their ease of recovery and recycle.

The first stage of this reaction illustrates the reactivity of hydrogen atom in a position of the nitrile group. 

Very recently the trans- [Pt(NH3)2Cl2] isomer has been shown to promote the formation of some highly unusual multiple strand nucleic acid structures (28). A parallel-stranded DNA duplex, psPtDNA, has been prepared which incorporates a frarcs-Pt(NH3)2+ crosslink. The pla-tinated strands were synthesized through the series of reactions illustrated in Fig. 3. The initial mono-functional G N7 adduct is formed at pH 3.5 by addition of rans-[Pt(NH3)2(H20)Cl]+ to the pyrimidine-rich sequence 5 -d(T4CT4G). After the pH is increased, normal anti-parallel duplex formation occurs upon addition of the complementary purine-rich strand, 5 -d(A4GA4G). This intermediate anti-parallel stranded... 

The following reaction illustrates conversion of a nitroxide radical-bearing alcohol by CDI and azide ion to a spin-labeled ester of azido formic acid, which is used for the labeling of amino acids, giving carbamates [137]... 

Like gas absorption, liquid-liquid extraction separates a homogeneous mixture by the addition of another phase - in this case, an immiscible liquid. Liquid-liquid extraction carries out separation by contacting a liquid feed with another immiscible liquid. The equipment used for liquid-liquid extraction is the same as that used for the liquid-liquid reactions illustrated in Figure 7.4. The separation occurs as a result of components in the feed distributing themselves differently between the two liquid phases. The liquid with which the feed is contacted is known as the solvent. The solvent extracts solute from the feed. The solvent-rich stream obtained from the separation is known as the extract and the residual feed from which the solute has been extracted is known as the raffinate. 

Van Wazer (19) has described the use of a redistribution reaction, illustrated in (5), to form linear oligomers from cyclic species ... 

Therefore, the sequence of reactions illustrated in Fig. 1 catalytically (the anthraquinone is regenerated) injects a radical cation into a DNA oligonucleotide that does not simultaneously contain a radical anion. As a result, the lifetime of this radical cation is determined by its relatively slow bimolecular reaction with H20 (or some other diffusible reagent such as 02- ) and not by a rapid intramolecular charge annihilation reaction. This provides sufficient time for the long distance migration of the radical cation in DNA to occur. 

The polymerization process for nylon 6 consists primarily of the three types of reaction illustrated in Fig. 23.6. Each of the reactions is reversible, tvith the equilibrium of the products being controlled primarily by the concentration of water in the reaction vessel. The reaction is initiated by the hydrolytic ring opening of caprolactam to form 6-aminohexanoic acid, as shown in Fig. 23.6 a). Chain extension of the type shotvn in Fig. 23.6 b) dominates when water is abundant (10 to 20%) in the reaction mixture. At lower water levels (2 to 5%) chains grow primarily by the mechanism shown in Fig. 23.6 c). In order to limit the average molecular... 

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