Toluene in acetonitrile

Figure 5.16 Influence of the fluorine-to-toluene equivalents (0.1 M toluene in acetonitrile) on conversion, selectivity and yield [13].

Figure 5. Oxidation of toluene in acetonitrile under oxygen products benzaldehyde ( ), benzyl alcohol ( ), o-cresol (O) m-cresol (O), p-cresol ( ).

Aromatic substrates studied in acetonitrile or acetic acid solutions were toluene, m-xylene, ethyl benzene cind mesitylene and the results are shown in Table I. For all the systems containing no or very little water, a zeroth order kinetic law in substrate concentration was obeyed. As the concentration of water present initially was successively increased, the order ultimately beceune disturbed cind finally a first-order law was estciblished. Figures 2 and 3 show the changeover in reaction order for the nitration of toluene in acetonitrile solution. 

It has been mentioned ( 4.4.2) that nitronium tetraffuoroborate reaets with pyridine to give i-nitropyridinium tetraffuoroborate. This compound and several of its derivatives have been used to effect what is called the transfer nitration ofbenzeneandtoluene. i-Nitropyridinium tetraffuoroborate is only sparingly soluble in acetonitrile, but its homologues are quite soluble and ean be used without isolation from the solution in which they are prepared. i-Nitropyridinium tetra-fluoroborate did nitrate toluene in boiling aeetonitrile slowly, but not at 25 In eontrast, i-nitro-2-pieolinium tetraffuoroborate readily... 

TABLE 4.5 Competitive nitrations of toluene and benzene with 1 -nitropyridinium tetrafluoroborates in acetonitrile at 25 °... 

This h)rpothesis has, however, been supported. The o p-ratio in chlorobenzene was found to be lower when acetic anhydride was the solvent, than when nitric acid or mixed acids were used. The ratio was still further reduced by the introduction into the solution of an even less polar solvent such as carbon tetrachloride, and was increased by the addition of a polar solvent such as acetonitrile. The orientation of substitution in toluene in which the substituent does not posses a strong dipole was found to be independent of the conditions used. The author... 

Trichloro- and dichloromethane, ether, dioxane, benzene, toluene, chlorobenzene, acetonitrile, or even pyridine itself has been employed to carry out the one-pot syntheses. Tliese solvents allow straightforward preparation of the salts. The temperature range between 0° and 20°C is usually employed and the salts formed are sufficiently soluble. In the case of slow reactions, selection of a solvent with a higher boiling point is prohtable since thermal instability of the A -(l-haloalkyl)heteroarylium halides has not been reported. Addition of water or an aqueous solution of sodium acetate does not cause a rapid decomposition of the salts so that this constitutes a useful step in the optimization of some procedures. 

The choice of reaction solvent is also of concern in the synthesis of new TSILs. Toluene and acetonitrile are the most widely used solvents, the choice in any given synthesis being dictated by the relative solubilities of the starting materials and products. The use of volatile organic solvents in the synthesis of ionic liquids is decidedly the least green aspect of their chemistry. Notably, recent developments in the area of the solventless synthesis of ionic liquids promise to improve this situation [10]. 

The results in the ionic liquid were compared with those obtained in four conventional organic solvents. Interestingly, the reaction in the ionic liquid proceeded with very high selectivity to give the a-arylated compound, whereas variable mixtures of the a- and (3-isomers were obtained in the organic solvents DMF, DMSO, toluene, and acetonitrile. Furthermore, no formation of palladium black was observed in the ionic liquid, while this was always the case with the organic solvents. 

The solvent in a bulk copolymerization comprises the monomers. The nature of the solvent will necessarily change with conversion from monomers to a mixture of monomers and polymers, and, in most cases, the ratio of monomers in the feed will also vary with conversion. For S-AN copolymerization, since the reactivity ratios are different in toluene and in acetonitrile, we should anticipate that the reactivity ratios are different in bulk copolymerizations when the monomer mix is either mostly AN or mostly S. This calls into question the usual method of measuring reactivity ratios by examining the copolymer composition for various monomer feed compositions at very low monomer conversion. We can note that reactivity ratios can be estimated for a single monomer feed composition by analyzing the monomer sequence distribution. Analysis of the dependence of reactivity ratios determined in this manner of monomer feed ratio should therefore provide evidence for solvent effects. These considerations should not be ignored in solution polymerization either. 

This category is represented in the facile reaction of o-phenylenediamine (408) with 4-benzoyl-5-phenyl-2,3-dihydro-2,3-thiophenedione (409) (in toluene at 20°C for 30 min) to afford 3-(a-benzoyl-p-mercaptostyryl)-2(l//)-qumoxalinone (410) in 98% yield " also in the complicated reaction of 3-methyl-2,2,4-trinitro-2,5-dihydrothiophene 1,1-dioxide (411) with 2 equiv of ethyl 4-aminobenzoate (412) (in acetonitrile but no further details) to give ethyl 2-(p-ethoxycarbonylphenyl)-3-(l-methyl-2-nitrovinyl)-6-quinoxalinecarboxylate (413) in 51% yield.Several... 

HydTOX5 proline-derived polyesters are usually readily soluble in a variety of organic solvents (benzene, toluene, chloroform, dichloro-methane, carbon tetrachloride, tetrahydrofuran, dimethylformamide, etc.) As expected, the solubility in hydrophobic solvents increased with increasing chain length of the N protecting group, while the solubility in polar solvents decreased. For example, poly(N-hexanoyl-hydroxyproline ester) is slightly soluble in ether but easily soluble in acetonitrile, while poly(N-palmitoylhydroxyproline ester) is readily soluble in ether but virtually insoluble in acetonitrile. 

The temperature was set to -15 °C [38] (see also [3]). The molar ratio of fluorine to toluene spans the range from 0.20 to 0.83 hence under-stochiometric fluorine contents were employed. The concentration of toluene in the solvent was 1.1 mol As liquid volume flow always 13 ml h was applied. Acetonitrile was used as solvent for the aromatic compound. In the gas phase, 10% fluorine in nitrogen was used. The gas volume flow was varied from 12.1 ml min to 50.0 ml min . ... 

Using methanol as solvent, the conversions ranged from 12 to 42% at selectivities of 9-58% [38]. This corresponds to yields of 3-14%. Hence the performance of the direct fluorination in methanol is generally worse than that in acetonitrile. The highest yield was found for a liquid volume flow of 11.1 ml h using a 1.1 mol 1 toluene concentration at -17 °C. The fluorine/toluene molar ratio was 0.925. 

GL 1] [R 4] [P 2] Selectivities of up to 36% at 33% conversion were achieved using acetonitrile as solvent (1.0 fluorine-to-toluene equivalent) [13]. When including multi-fluorinated toluenes and chain-fluorinated toluenes, in addition to the mono-fluorinated toluenes, in the selectivity balance, the value increases to 49%. The remainder is lost in other side reactions such as additions or polymerizations. 

Solvents for PTC should be nonhydroxylic and immiscible with water. CHCI3, CH2CI2, chlorobenzene, toluene, and acetonitrile are commonly employed. If the reactant is liquid, extra solvent is not required. Although chloroform and methylene chloride are favourable from a chemistry point of view, engineering considerations often lead to the choice of chlorobenzene (and toluene) because of their lower solubility in water and higher boiling point. 

However, pMBCl 42 has a thermal stability issue and is expensive (Aldrich price 25 g for 69.90 the largest bottle). On the other hand, pMBOH 43 is stable and economically viable (Aldrich price 500 g for 84.90 the largest bottle). It was found that mono-N-alkylation of 36 proceeded well by slow addition (over 3 h) of 43 to a solution of 36 in acetonitrile in the presence of a catalytic amount of acid (p-TsOH) at 70 °C, as shown in Scheme 1.16. Slow addition of alcohol 43 minimized the self-condensation of 43 to form symmetrical ether 44, which was an equally effective alkylating agent. The product 41 was then directly crystallized from the reaction mixture by addition of water and was isolated in 90% yield and in >99% purity. A toluene solution of 41 can be used for the next reaction without isolation but the yield and optical purity of the asymmetric addition product were more robust if isolated 41 was used. In general, the more complex the reaction, the purer the starting materials the better. 

Conditions for the safe preparation of the diisocyanate from adipoyl chloride and sodium azide in acetonitrile-toluene mixtures were established. 

The cartridge was preconditioned with 0.5 mL toluene and each of the above benzodiazepine solutions passed through it. Analytes retained on the MIP were eluted with 0.5 mL of 15% acetic acid in acetonitrile. Internal standard (corresponding deuterated benzodiazepine) was added and subjected to LC/MS/MS. The results obtained for recovery, limit of detection (LOD), and quantitation (LOQ) are shown in Table 1.22. The binding capacity of diazepam to the templated MIP was found to be 110 ng/mg polymer. The same results were obtained for postmortem hair samples. 

Several Ru(III) salen complexes of the type Ruin(salen)(X)(NO) (X=C1-, ONO-, H20 salen = N,AP-bis(salicylidene)-ethylenediamine dianion) have been examined as possible photochemical NO precursors (19). Photo-excitation of the Rum(salen)(NO)(X) complex labilizes NO to form the respective solvento species Ruin(salen)(X)(Sol). The kinetics of the subsequent back reactions to reform the nitrosyl complexes (e.g. Eq. (8)) were studied as a function of the nature of the solvent (Sol) and reaction conditions. The reaction rates are dramatically dependent on the identity of Sol, with values of kNO (298 K, X = C1-) varying from 5 x 10-4 M-1 s-1 in acetonitrile to 4 x 107 M-1 s-1 in toluene, a much weaker electron donor. In this case, Rum Sol bond breaking clearly... 

The alkaloid whitasomnine 44 was prepared according two different routes. The first approach (route A) was based on the cyclization of the l-(3-chloropropyl)cyclopropanol 41 (Scheme 3). The final cyclization involved the reaction of 3-(3-chloropropyl)pyrazole 42 to form the final pyrazole 43 in 40% yield, which is then transformed to the natural product <1996TL1095>. The second approach (route B) is based on the radical cyclization of the substituted pyrazole 45 in the presence of Bu3SnH in acetonitrile under refluxing toluene. Whitasomnine 44 was isolated in 38% yield <2002TL4191>. 

MethyM-cthoxycarbonyl-5-bcnzoyl-hydrazino-l //-pyrazole 274, prepared by reacting benzoyl chloride and 3-methyM-cthoxycarbonyl-5-bcnzoyl-hydrazino-l //-pyrazole hydrochloride 273, in the presence of pyridine in acetonitrile, has been cyclized with phosphoryl chloride in benzene or toluene to give 7-ethoxycarbonyl-6-methyl-3-phenyl-l //-pyrazolo[5,l -/ 1,2,4 triazolc 55. This compound has been also synthesized through cyclization of... 

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