Typical Reaction Conditions

Reaction times typically range from milliseconds to 10 s, although exchange times up to 40 s have been accomplished [13]. Furthermore, when a pulsed deuterating agent introduction system is not used, the actual reaction time is approximately the sum of the ion accumulation time, any isolation time, and any exchange time, since the deuterating 

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Intramolecular Friedel-Crafts substitution has also figured prominently in the synthesis of oxindoles from cx-haloacelanilides. Typical reaction conditions for cyclizalion involve heating with A1CI,[13-17]. 

The carboaylatioa of methanol to give formic acid is carried out ia the Hquid phase with the aid of a basic catalyst such as sodium methoxide. It is important to minimi2e the presence of water and carbon dioxide ia the startiag materials, as these cause deactivatioa of the catalyst. The reactioa is an equHibrium, and elevated pressures are necessary to give good conversions. Typical reaction conditions appear to be 80°C, 4.5 MPa (44 atm) pressure and 2.5% w/w of catalyst. Under these conditions the methanol conversion is around 30% (25). 

Typical reaction conditions are 150 to 300°C and up to 2 MPa pressure. Polyalkenyl succinic anhydrides are prepared under these conditions by the reaction of polyalkenes in a nonaqueous dispersion of maleic anhydride, mineral oil, and surfactant (33). 

The Boekelheide reaction has been applied to the synthesis of non-natural products with the preparation of quaterpyridines serving as an example. The sequence began with the 2,4-linked bipyridyl-N-oxide 25. Execution under the typical reaction conditions produced the expected bis-pyridone 26. Treatment with POCI3 afforded the corresponding dichloride that was submitted to a palladium-catalyzed coupling with 2-stannyl pyridine to produce the desired quaterpyridine 27. 

Oxidation of C12-C14 n-paraffms using boron trioxide catalysts was extensively studied for the production of fatty alcohols.Typical reaction conditions are 120-130°C at atmospheric pressure. ter-Butyl hydroperoxide (0.5 %) was used to initiate the reaction. The yield of the alcohols was 76.2 wt% at 30.5% conversion. Fatty acids (8.9 wt%) were also obtained. Product alcohols were essentially secondary with the same number of carbons and the same structure per molecule as the parent paraffin hydrocarbon. This shows that no cracking has occurred under the conditions used. The oxidation reaction could be represented as ... 

Many different catalysts are available for this reaction. AlCls-EiCl is commonly used. Ethyl chloride may be substituted for EiCI in a mole-for-mole basis. Typical reaction conditions for the liquid-phase AICI3 catalyzed process are 40-100°C and 2-8 atmospheres. Diethylbenzene and higher alkylated benzenes also form. They are recycled and dealky-lated to EB. 

Both primary and secondary amines add to a /S-unsaturated aldehydes and ketones to yield /3-amino aldehydes and ketones rather than the alternative imines. Under typical reaction conditions, both modes of addition occur rapidly. But because the reactions are reversible, they generally proceed with thermodynamic control rather than kinetic control (Section 14.3), so the more stable conjugate addition product is often obtained to the complete exclusion of the less stable direct addition product. 

The heats of these reactions (2, 3) (Figure 1) indicate that all the reactions are exothermic over the cited range of conditions. For example, the heat liberated under typical reaction conditions for the conversion of CO to methane is 52,730 cal/mole CO that for carbon dioxide is 43,680 cal/mole. Such high heats of reaction cannot be absorbed by the process stream in an adiabatic reactor unless the CO and/or C02 conversion is limited to less than about 2.5 moles/100 moles feed gas. Since... 

Alicyclic ew-dialkyldiazenes are very thermolabile when compared to the corresponding tram-isomers, often having only transient existence under typical reaction conditions. It has been proposed49 that the main light-induced reaction of the dialkyldiazenes is tram-cis isomerization. Dissociation to radicals and nitrogen is then a thermal reaction of the cis-isomer (Scheme 3.19),... 

Sulfate radical anion may be converted to the hydroxyl radical in aqueous solution. Evidence for this pathway under polymerization conditions is the formation of a proportion of hydroxy end groups in some polymerizations. However, the hydrolysis of sulfate radical anion at neutral pi I is slow (k— 107 M"1 s 1) compared with the rale of reaction with most monomers (Ar=l08-109 M 1 s 1, Table 3.7)440 under typical reaction conditions. Thus, hydrolysis should only be competitive with addition when the monomer concentration is very low. The formation of hydroxy end groups in polymerizations initiated by sulfate radical anion can also be accounted for by the hydration of an intermediate radical cation or by the hydrolysis of an initially formed sulfate adduct either during the polymerization or subsequently. 

Further lowering the dielectric constants has been achieved by preparing highly fluorinated polyethers without any sulfone, ketone, or other polarizable groups.239 241 Typically, the /jara-lluorinc atoms on highly fluorinated aromatic compounds, such as hexafluorobenzene and decafluorobiphenyl, are activated and thus can go through aromatic nucleophilic substitution with HFBPA under typical reaction conditions (Scheme 6.31).217... 

Typical reaction conditions for these reagents are shown below. Propose mechanisms by which these heterocyclic molecules can function to activate carboxy groups under these conditions. 

Scheme 4.1 includes examples of oxymercuration reactions. Entries 1 and 2 illustrate the Markovnikov orientation under typical reaction conditions. The high exo selectivity in Entry 3 is consistent with steric approach control on a weakly bridged (or open) mercurinium ion. There is no rearrangement, indicating that the intermediate is a localized cation. 

The focus of Part B is on the closely interrelated topics of reactions and synthesis. In each of the first twelve chapters, we consider a group of related reactions that have been chosen for discussion primarily on the basis of their usefulness in synthesis. For each reaction we present an outline of the mechanism, its regio- and stereochemical characteristics, and information on typical reaction conditions. For the more commonly used reactions, the schemes contain several examples, which may include examples of the reaction in relatively simple molecules and in more complex structures. The goal of these chapters is to develop a fundamental base of knowledge about organic reactions in the context of synthesis. We want to be able to answer questions such as What transformation does a reaction achieve What is the mechanism of the reaction What reagents and reaction conditions are typically used What substances can catalyze the reaction How sensitive is the reaction to other functional groups and the steric environment What factors control the stereoselectivity of the reaction Under what conditions is the reaction enantioselective ... 

Similarly applicable for ester syntheses as CDI is A AT -oxalyldiimidazole, which was first described in reference [109]. It has been used to convert not only carboxylic acids but also metal carboxylates into the corresponding imidazolides.[110] Typical reaction conditions for the reactions with oxalyldiimidazole are for the first step 1-2 h, 25-45 °C, and for the second step 4 h, room temperature if X = H if X = Li or Na, if 60 °C and DMF as solvent. In the latter case the resulting Lilm or Naim function as catalysts in the conversion of alcohol into the alcoholate. Results are given in Table 3— 3 [no]... 

Aromatic saturation reactions are reversible and exothermic, and at typical reaction conditions, do not attain 100% conversion. Furthermore, increasing the temperature to favor conversion of the other concurrent reactions disfavor aromatic hydrogenation. The kinetics studies indicate that they are fast reactions, indicating that equilibrium is reached under HDT conditions. 

The amidine bond formed is quite stable at acid pH however, it is susceptible to hydrolysis and cleavage at high pH. A typical reaction condition for using imidate crosslinkers is a buffer system consisting of 0.2 M triethanolamine in 0.1 M sodium borate, pH 8.2. After conjugating two proteins with a bifunctional imidoester crosslinker, excess imidoester functional groups may be blocked with ethanolamine. 

JME538, 1997CH739>. The main thiadiazole product 185, however, suffered chlorination in the a-position. The isolation of 2-amino acrylonitrile 184 from the reaction mixture supported decomposition of the 2-oximino acetonitrile 183 furthermore, treatment of the pure acrylonitrile under typical reaction conditions gave exclusively ot-chloro-3-chloro-l,2,5-thiadiazole 185 (Scheme 27 Table 11). Mechanisms explaining the formation of both thiadiazoles were proposed <1998H(48)2111>. 

Table 19.3 Typical reaction conditions for the hydrogenation of polybutadiene (PB), styrene-butadiene diblock copolymer (SB), styrene-butadiene-styrene triblock copolymer (SBS) and nitrile butadiene rubber (NBR).

Bikiaris and Karayannidis [5] have investigated the use of diimidodiepoxides as chain extenders for PET resins. Starting with a PET having an IV of 0.60 dL/g and a carboxyl content (CC) of 42 eq/106 g, they obtained PET with an IV of 1.16 dL/g and a CC below 5 eq/106 g. The typical reaction condition for the coupling of PET was heating with the chain extender under an argon atmosphere above its melting temperature (280 °C) for several minutes. 

Typical reaction conditions, products, and yields are depicted in Scheme 8 for acetals [32, 33]. 

The new polymers 9-28 were synthesized by the Pd-catalyzed reaction of (4,4 - or 5,5 -dibromo-2,2 -bipyridine)-bis(4,4 -terf-butyl-2,2 -bipyridine or 2,2 -bipyridine)ruthenium(II) complexes 5-8 and diethynylarenes (Table 2) in a step-growth polycondensation mechanism (Scheme 4). The typical reaction conditions used for the synthesis of the polymers involved stirring the argon-... 

This approach can offer several advantages. First, polymers can be formed from monomers that do not give polymer under more typical reaction conditions. Second, under some cases, the crystalline structure acts as a template giving the order that might otherwise be difficult to achieve. Third, removal and interference by solvent or additives is eliminated as they are not present. Fourth, the polymers produced by this technique are often different from those from the same monomer except that produced using typical reaction techniques. 

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