The Reactions Used

For example, (1) an octadecadienoic acid is made to react directly with an amine of the formula  

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The reaction uses triethyl phosphate as a homogeneous catalyst. ... 

The reaction uses a fixed-bed vanadium pentoxide-titanium dioxide catalyst which gives good selectivity for phthalic anhydride, providing temperature is controlled within relatively narrow limits. The reaction is carried out in the vapor phase with reactor temperatures typically in the range 380 to 400°C. 

Basic Organic Chemistry , J. M. Tedder, A. Nechvatal, and others, Wiley, 5 volumes 1966-1976. A complete textbook of organic chemistry. Explains all the reactions used in the programme and describes many syntheses in detail. 

Principles of Organic Synthesis", R. 0. C. Norman, Methuen, 1968 A taxtbook of organic chemistry from the point of view of synthesis. An excellent source book for all the reactions used in this programme. 

The dibromodioxane crystals are now ready for the reaction. Using the same ice bath as before we have a PP beaker containing 100g of benzodioxole and 200ml of ether, which is being stirred. We gently add 200g of dibromodioxane crystals and watch the... 

Coulometric Titrations Controlled-current coulometric methods commonly are called coulometric titrations because of their similarity to conventional titrations. We already have noted, in discussing the controlled-current coulometric determination of Fe +, that the oxidation of Fe + by Ce + is identical to the reaction used in a redox titration. Other similarities between the two techniques also exist. Combining equations 11.23 and 11.24 and solving for the moles of analyte gives... 

The i5p-titanium(IV) atom is hard, ie, not very polarizable, and can be expected to form its most stable complexes with hard ligands, eg, fluoride, chloride, oxygen, and nitrogen. Soft or relatively polarizable ligands containing second- and third-row elements or multiple bonds should give less stable complexes. The stabihty depends on the coordination number of titanium, on whether the ligand is mono- or polydentate, and on the mechanism of the reaction used to measure stabihty. 

The oxidation proceeds rapidly under the catalytic influence of the oxides of nitrogen formed, but there is sometimes difhculty in starting the reaction using pure nitric acid. In this case the checkers found it convenient to oxidize a few drops of the chlorohydrin with nitric acid by heating in a test tube and to add this to the nitric acid in the flask without stirring. A small portion of the chlorohydrin is then added and allowed to react for a few minutes before starting the stirrer and continuing the oxidation of the main lot. 

A particularly elegant route to metallacarbor-anes is the direct oxidative insertion of a metal centre into a c/oso-carborane cluster the reaction uses zero-valent derivatives of Ni, Pd and Pt in a concerted process which involves a nett transfer of electrons from the nucleophilic metal centre to the cage ... 

In most of the successful Diels-Alder reactions reported, dienes containing no heteroatom have been employed, and enantioselective Diels-Alder reactions of multiply heteroatom-substituted dienes, e.g. Danishefsky s diene, are rare, despite their tremendous potential usefulness in complex molecular synthesis. Rawal and coworkers have reported that the Cr(III)-salen complex 15 is a suitable catalyst for the reaction of a-substituted a,/ -unsubstituted aldehydes with l-amino-3-siloxy dienes [21] (Scheme 1.28, Table 1.12). The counter-ion of the catalyst is important and good results are obtained in the reaction using the catalyst paired with the SbFg anion. 

When the catalyst coordinates to the pyrazoline nitrogen and carbonyl oxygen at the step of 1-pyrazoline formation, desilylation or deprotonation takes place at the same position to give either Na or Nb, respectively. On the other hand, when the catalyst coordinates to the two carbonyl oxygens, the methine hydrogen derived from the acceptor molecule is deprotonated to give Nc. In the reaction using a Le-... 

Recently, enhanced endo selectivity has been reported in the Diels-Alder reaction of fE -l-acetoxybuta-l,3-dienes with methyl fi-nitroacrylate The selectivity is compared with that of the reaction using l-methoxybuta-l,3-dienes and 1-trimethylsilyloxybuta-1,3-di-enes The degree of electron richness of a diene is an important consideration in endo eKO selectivity issues In particular, electron-rich dienes favor the formation of fixc-nitrocycload-ducts fEq 8 9 ... 

A related study used the air- and moisture-stable ionic liquids [RMIM][PFg] (R = butyl-decyl) as solvents for the oligomerization of ethylene to higher a-olefins [49]. The reaction used the cationic nickel complex 2 (Figure 7.4-1) under biphasic conditions to give oligomers of up to nine repeat units, with better selectivity and reactivity than obtained in conventional solvents. Recycling of the catalyst/ionic liquid solution was possible with little change in selectivity, and only a small drop in activity was observed. 

Problem 7.19 Oik- of the chain-termination steps that sometimes occurs to interrupt polymerization is the following reaction between two radicals. Propose a mechanism for the reaction, using fishhook arrows to indicate electron flow. 

One of the reactions used in determining the sequence ot nucleotides in a strand of DNA is reaction with hydrazine. Propose a mechanism for the following reaction, which occurs by an initial conjugate addition followed by internal amide formation. 

When water is added to a mixture of aluminum metal and sodium hydroxide, hydrogen gas is produced. This is the reaction used in commercial drain cleaners ... 

Strategy Choose the first two concentrations, 0.20 M and 0.30 M. Calculate the ratio of the rates, the ratio of the concentrations, and finally the order of the reaction, using the general relation derived above. 

The negative sign of AG° implies that although Fe203 does not spontaneously decompose, it can be converted to iron by reaction with carbon monoxide. This is in fact the reaction used in the blast furnace when iron ore consisting mainly of Fe203 is reduced to iron (Chapter 20). 

Some of the reactions used to prepare transuranium elements are listed in Table 19.1. Neutron bombardment is effective for the lower members of the series (elements 93 through... 

In such reactions, even though the indicator electrode functions reversibly, the maximum value of AE/AV will not occur exactly at the stoichiometric equivalence point. The resulting titration error (difference between end point and equivalence point) can be calculated or can be determined by experiment and a correction applied. The titration error is small when the potential change at the equivalence point is large. With most of the reactions used in potentiometric analysis, the titration error is usually small enough to be neglected. It is assumed that sufficient time is allowed for the electrodes to reach equilibrium before a reading is recorded. 

The temperature profiles for each catalyst at two different space velocities are plotted in Figure 1. The catalysts with lower nickel content had reasonable activity, but the activity obviously decreased with nickel content. At 25,000/hr space velocity, the 30% nickel-on-alumina catalyst used 50% of the bed to obtain the maximum temperature whereas with 50% nickel the reaction used only 30% or the bed. The method used to prepare the C150-3-02 catalyst resulted in a non-reduceable nickel silicate... 

The high sensitivity of the MS [160] makes it a particularly appropriate tool for the investigation of nucleation and growth processes, since it is possible to measure rates during the early part of the reaction using small samples or individual crystals. The influence of residual gases [160] on the initiation of reaction can also be determined. Short scan times enable very rapid reactions e.g. detonations, to be studied, and it is also possible to measure simultaneously the rate of evolution of several different product molecules. 

The activity coefficients in the above equation may be determined by obtaining experimental data for D/ m, and relating Ka to the free energy change for the reaction using the equation AGf = -RT In K. 

The submitters performed the reaction using a 0.12 mmol excess of Fmoc-L-Asp-Ot-Bu, under which conditions aminomethylated polystyrene resin was required to remove the excess carboxylic acid (Note 13). The checkers modified the reaction to use 0.28 mmol excess Disperse Red 1. The initial Amberlyst-15 filtration removes this material. 

H.4 The first box below represents the reactants for a chemical reaction and the second box the products that form if all the reactant molecules shown react. Using the key below write a balanced equation for the reaction using the smallest whole-number coefficients. Assume that if two atoms are touching,... 

One difficulty Haber faced is that the reactions used to produce compounds from nitrogen do not go to completion, but appear to stop after only some of the reactants have been used up. At this point the mixture of reactants and products has reached chemical equilibrium, the stage in a chemical reaction when there is no further tendency for the composition of the reaction mixture—the concentrations or partial pressures of the reactants and products—to change. To achieve the greatest conversion of nitrogen into its compounds, Haber had to understand how a reaction approaches and eventually reaches equilibrium and then use that... 

Self-Test 13.4B The highly toxic gas carbonyl chloride, COCl2 (phosgene), is used to synthesize many organic compounds. Use the following data to write the rate law and determine the value of k for the reaction used to produce carbonyl chloride ... 

The second part is a review of the materials deposited by CVD, i.e., metals, non-metallic elements, ceramics and semiconductors, and the reactions used in their deposition. 

The convergent approach overcomes these problems to an extent, but still gives more or less imperfect structures depending on the purity of the reagents and the efficiency of the reactions used. 

In the aldol reaction the a carbon of one aldehyde or ketone molecule adds to the carbonyl carbon of another. Although acid catalyzed aldol reactions are known, the most common form of the reaction uses a base. The base most often used is OH, though stronger bases such as alkoxides (RO ) are sometimes employed. Hydroxide ion is not a strong enough base to convert substantially all of an aldehyde or ketone molecule to the corresponding enolate ion, that is, the equilibrium lies... 

Most of the reactions using the reduction of an oxide by an electropositive metal are energetically self-sustaining and consequently are fast. 

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