Chloroform-acetonitrile

The importance of the solvent, in many cases an excess of the quatemizing reagent, in the formation of heterocyclic salts was recognized early. The function of dielectric constants and other more detailed influences on quatemization are dealt with in Section VI, but a consideration of the subject from a preparative standpoint is presented here. Methanol and ethanol are used frequently as solvents, and acetone,chloroform, acetonitrile, nitrobenzene, and dimethyl-formamide have been used successfully. The last two solvents were among those considered by Coleman and Fuoss in their search for a suitable solvent for kinetic experiments both solvents gave rise to side reactions when used for the reaction of pyridine with i-butyl bromide. Their observation with nitrobenzene is unexpected, and no other workers have reported difficulties. However, tetramethylene sulfone, 2,4-dimethylsulfolane, ethylene and propylene carbonates, and salicylaldehyde were satisfactory, giving relatively rapid reactions and clean products. Ethylene dichloride, used quite frequently for Friedel-Crafts reactions, would be expected to be a useful solvent but has only recently been used for quatemization reactions. ... 

From empirical observation, ILs tend to be immiscible with non-polar solvents. They can therefore be washed or brought into contact with diethyl ether or hexane to extract non-polar reaction products. Among solvents of greater polarity, esters (ethyl acetate, for example) exhibit variable solubility with ILs, depending on the nature of the IL. Polar or dipolar solvents (including chloroform, acetonitrile, and methanol) appear to be totally miscible with all ILs (excepting tetrachloroaluminate IL and the like, which react). Among notable exceptions, [EMIMJCl and [BMIMJCl are insoluble in dry acetone. 

The reaction is complete after one to two hours at room temperature. Amides are usually obtained in very good yields. A wide range of solvents can be used, including tetrahydrofuran, chloroform, acetonitrile, dimethylformamide, and benzene. 21 The reaction can also be carried out in the melt. Examples have been collected in the following pages. In some cases the intermediate imidazolides were isolated, but the reactions are preferably carried out as one-pot reactions . 

Lesser et al (75) used cellulose sheets with fluorescent indicator, acetic acid/0.01M aqueous disodium edetate (3 97), and observed an Rf value of O.78 for hydralazine. On silica gel with fluorescent indicator, the Rf value was less than 0.05 with (a) chloroform/n-heptane/ acetic acid (6 4 1), and (b) cyclohexane/chloroform/ acetonitrile (1 2 1). 

Solvent methods are similar to in situ polymerizations. During the first stage, the nanomaterial is dispersed in a solvent. In some cases a surfactant can be used as a bridge between the nanomaterials and the matrix (Fig. 4.9). This reaction occurs in a liquid or gel form in the presence of a solvent such as toluene, chloroform, acetonitrile, water, acetone, etc. The solution of modified nanoparticles is then added to a polymeric solution under agitation (at room or elevated temperatures) in order to ensure a homogeneous dispersion of the nanomaterials in the matrix. Finally, the polymer composite... 

Adsorption of a specific probe molecule on a catalyst induces changes in the vibrational spectra of surface groups and the adsorbed molecules used to characterize the nature and strength of the basic sites. The analysis of IR spectra of surface species formed by adsorption of probe molecules (e.g., CO, CO2, SO2, pyrrole, chloroform, acetonitrile, alcohols, thiols, boric acid trimethyl ether, acetylenes, ammonia, and pyridine) was reviewed critically by Lavalley (50), who concluded that there is no universally suitable probe molecule for the characterization of basic sites. This limitation results because most of the probe molecules interact with surface sites to form strongly bound complexes, which can cause irreversible changes of the surface. In this section, we review work with some of the probe molecules that are commonly used for characterizing alkaline earth metal oxides. 

The [Cu[Sb(C6Hs)3] 3(N03)] complex is soluble in chloroform, acetonitrile, benzene, and jV.jV-dimethylformamide. In the last two solvents, oxidation of the copper(I) complex is evidenced by the formation of green solutions on standing. Thermal analyses (DSC and TGA in air) show a weight loss above 141° associated with an exothermic reaction. 

Nitric acid, Urea, Sulfuric acid, Nitronium tetrafluoroborate. Anhydrous ammonia. Acetonitrile, Ethyl acetate. Chloroform Acetonitrile, Ammonium carbonate. Isopropyl alcohol, Nitronium tetrafluoroborate. Anhydrous ammonia. Diethyl ether. Acetone, Butanol, Ethyl acetate... 

Diels-Alder reaction (Benzene, toluene, water, methanol, ethanol, diethyl ether, tetrahydrofuran, 1,4-dioxane, acetone, CHjCb, 1,2-dichloroethane, o-dichlorobenzene, chloroform, acetonitrile)... 

The polymers had molecular weights of several million, but were completely soluble in water and some organic solvents such as chloroform, acetonitrile, ethylene dichloride and acetic acid. The water solubility results apparently from strong hydrogen bonding between solvent and ether groups but appears to be peculiar to the polyethylene oxides for it is not observed with polyformaldehyde, polyacetaldehyde or poly-... 

The macrocyclic compound 227 after decomposition in a chloroform/acetonitrile mixture (1 4) gave after 4 h at room temperature the dithiete 225 and thiocine 226 in 6% and 12% yield, respectively (Equation 48) <1998JOC8192>. 

Fucoxanthin its esters separation Chinese clam Reverse Phase, C18 column Chloroform Acetonitrile (3 7v/v) Isocratic Maoka et al., 2007... 

Dooley and Patterson (81) reported further investigations of the photooxidation of [M(mnt)212 (M = Ni, Pd, Pt, Co, Cu) in a 24 1 chloroform/acetonitrile solvent mixture. Again, clean photochemistry was observed, with several isosbestic points in the overlaid UV-vis spectra shown in Fig. 3. For... 

One of the common properties of imidazole N-oxides is their strong association even in dilute solution, and in the solid state such association can mask distinction in the IR between NH and OH bands. Thus IR studies of such compounds in the solid state may give rise to confusing results. Careful UV studies of 1-hydroxybenzimidazoles show that with a variety of substituents (e.g. 6-nitro, 2-alkyl or 2-aryl) the hydroxy form (73) is favoured in organic solvents, and the more polar oxide form (74) in water (there is a mixture of both in aqueous ethanol). With 1-hydroxybenzimidazole the N-methyl model (75) is not sterically hindered, and the value of Kt (74173) = 12 deduced from the pK values of the models (75/76) in water should be much more reliable than that for the hydroxyimidazoles (Scheme 24). In other solvents (benzene, chloroform, acetonitrile, dioxane), UV results show that the OH form (73) predominates in 75% aqueous ethanol Kt=1. 

Only a few examples of arenetellurinyl carboxylates, the mixed anhydrides of tellurinic acids and carboxylic acids, are known. These eompounds were prepared by refluxing mixtures of arenetellurinic acid anhydrides with acetic or trifluoroacetic acid or their anhydrides in chloroform . Acetonitrile and 1,2-dichloroethane were also used as solvents. Benzenetellurinyl trifluoroacetate is described as a very hygroscopic, intractable oil. The arenetellurinyl acetates are solids with melting points of approximately 150°. 

Irrespective of the detection method used, the analysis of VOCs often involves the presence of interferences in the chromatogram. This is normally due to VOCs present in the atmosphere, such as normal laboratory solvents (acetone, dichloromethane, chloroform, acetonitrile, or methanol) which can be detected, especially when using a universal detector such as a mass spectrometer which operates under vacuum. This problem is eliminated when the laboratory of analysis is free of solvents and is isolated, especially from urban areas. 

Szepesi et al. reported an ion-pair separation of eburnane alkaloids on a chemically bonded cyanopropyl stationary phase. As counter-ion, di-(2-ethyl hexyl)phosphoric acid or (+)-10-camphorsulfonic acid were used in a mobile phase consisting of hexane - chloroform -acetonitrile mixtures (Table 8.8, 8.9). Because of the poor solubility of the latter pairing ion, diethylamine (Table 8.9) was added to the mobile phase. Addition of diethylamine considerably reduced the k1 of the alkaloids, due to suppression of the ionization of the alkaloids. However, due to the strong acidic character of the pairing ion, ion-pairs were still formed under these conditions. The camphorsulfonic acid containing mobile phases were found to be very useful for the separation of optical isomers (Table 8.10, 8.11, Fig.8.8) 6. It was also found that the selectivity of the system could be altered by choosing different medium-polarity solvents (moderator solvents) as dioxane, chloroform or tetrahydrofuran. The polar component of the solvent system affected peak shape. Based on these observations, a method was developed to analyze the optical purity of vincamine and vinpocetine. For the ana-... 

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