Hydration, acetonitrile

Honda M, Kuno S, Begum N, Fujimoto K-I, Suzuki K, Nakagawa Y, Tomishige K (2010) Catalytic synthesis of dialkyl carbonate from low pressure CO2 and alcohols combined with acetonitrile hydration catalyzed by Ce02. App Catal A Gen 384(1-2) 165-170... 

Martin M, Horvath H, Sola E, Katho A, Joo F (2009) Water-soluble triisopropylphosphine complexes of ruthenium(II) synthesis, equilibria, and acetonitrile hydration. Organometallics 28 561... 

Industrial production is often based on transformation of this laboratory method into a continuous process (10). Another route is acetonitrile [75-05-8] hydration ... 

Because huge quantities of by-product acetonitrile are generated by ammoxidation of propylene, the nitrile may be a low cost raw material for acetamide production. Copper-cataly2ed hydration gives conversions up to 83% (11), and certain bacteria can effect the same reaction at near room temperature (12). 

X 10 J/T (5.71 //g) at room temperature. It is air stable at 25°C, but is slowly converted to Fe202 and bromine at 310°C. The light yellow to brown hydroscopic sohd is soluble ia water, alcohol, ether, and acetonitrile. Iron(II) bromide forms adducts with a wide range of donor molecules. Pale green nona-, hexa-, tetra-, and dihydrate species can be crystallized from aqueous solutions at different temperatures. A hydrate of variable water content,... 

The hydration of 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4-ethynylpyrazole was performed with p-toluenesulfonic acid monohydrate in acetonitrile (2 h, room temperature) to give the corresponding 4-acetyl derivative. An alkyl substituent at the triple bond decreases the rate of hydration the conversion of 5-amino-3-cyano-l-(2,6-dichloro-4-trifiuoromethylphenyl)-4-(prop-l-yn-l-yl) pyrazole to the 4-propanoylpyrazole was completed after 18 h (98INP9804530 99EUP933363). 

HPLC on a PRP-1 column (0.7 x 30.5 cm, Hamilton), with 65% acetonitrile containing 0.05% acetic acid, at a flow rate of 4 ml/min. To reverse the possible hydration of the molecules, the material obtained in step 3 is first evaporated to dryness, and redissolved in chloroform. Immediately before injection onto the HPLC column, an... 

Both PS-A and PS-B have a tendency to hydrate like panal, and they also form adducts with methylamine. The adducts, PS-A/MA and PS-B/MA, are prepared by incubating PS-A or PS-B in 75 % methanol containing an excess amount of methylamine hydrochloride plus some sodium acetate to neutralize the HC1, at 45°C for 30 min. The adducts can be purified by HPLC on a PRP-1 column (80% acetonitrile containing 0.05% acetic acid). Their chemical structures have been determined by NMR and mass spectrometry as shown in Fig. 9.8 (p. 288). Both adducts are colorless and show an absorption maximum at 218 nm. 

Aqueous solutions are not suitable solvents for esterifications and transesterifications, and these reactions are carried out in organic solvents of low polarity [9-12]. However, enzymes are surrounded by a hydration shell or bound water that is required for the retention of structure and catalytic activity [13]. Polar hydrophilic solvents such as DMF, DMSO, acetone, and alcohols (log P<0, where P is the partition coefficient between octanol and water) are incompatible and lead to rapid denaturation. Common solvents for esterifications and transesterifications include alkanes (hexane/log P=3.5), aromatics (toluene/2.5, benzene/2), haloalkanes (CHCI3/2, CH2CI2/I.4), and ethers (diisopropyl ether/1.9, terf-butylmethyl ether/ 0.94, diethyl ether/0.85). Exceptionally stable enzymes such as Candida antarctica lipase B (CAL-B) have been used in more polar solvents (tetrahydrofuran/0.49, acetonitrile/—0.33). Room-temperature ionic liquids [14—17] and supercritical fluids [18] are also good media for a wide range of biotransformations. 

The action of anhydrous iron (ili) perchlorate on acetonitrile gives rise to an extremely violent reaction. If the perchlorate is hydrated, it is not the same. 

Schemes 6-18 A plausible mechanism of hydration of acetonitrile catalyzed by unhindered hydridobis(phosphine)platinum(II) complexes...

We also found that iridium hydrido(hydroxo) complexes like [ lrH(diphos-phine) 2( x-OH)2( x-Cl)]Cl (43) and the precursor diphosphine complexes 42 can also catalyze the hydration of nitriles. In the presence of catalyhc amounts of these complexes, heating acetonitrile and benzonitrile with excess water at 120°C gave the corresponding amides [47, 50]. 

The catalyst reported by Grotjahn and Lev (11-13) for alkyne hydration (2) is capable of isomerizing alkenes, but veiy slowly. Because we knew that the rate of alkyne hydration was unchanged in the presence of excess phosphine ligand, we thought that like alkyne hydration, alkene isomerization would require loss of acetonitrile ligand (14) and alkene binding. Subsequent deprotonation at an allylic position would make an q -allyl intermediate which when reprotonated at the other... 

The violent reaction which occurred on dissolution of the anhydrous salt in acetonitrile did not occur with the hydrated salt. 

Apart from the qualitative observations made previously about suitable solvents for study, the subject of solvates has two important bearings on the topics of thermochemistry which form the main body of this review. The first is that measured solubilities relate to the appropriate hydrate in equilibrium with the saturated solution, rather than to the anhydrous halide. Obviously, therefore, any estimate of enthalpy of solution from temperature dependence of solubility will refer to the appropriate solvate. The second area of relevance is to halide-solvent bonding strengths. These may be gauged to some extent from differential thermal analysis (DTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) solvates of "aprotic solvents such as pyridine, tetrahydrofuran, and acetonitrile will give clearer pictures here than solvates of "protic solvents such as water or alcohols. 

The fluorination of nitroalkanes has been described. A solution of acetyl hypofluo-rite, AcOF, is prepared by passing fluorine, diluted with nitrogen, into a cold suspension of hydrated sodium acetate in acetonitrile containing acetic acid. Adding a mixture of a nitroalkane and methanolic sodium methoxide yields the fluorinated nitroalkane, e.g. 1-fluoro-l-nitrocyclopentane from nitrocyclopentane417. A general method for alkylating nitroalkanes is exemplified by the reaction of the sodium nitronate 376 with the benzotriazole derivative 377 to yield 378418. 

These and related incidents are detailed under f Acetonitrile, Lanthanide perchlorate, 0758 Chromium(III) perchlorate. 6 dimethyl sulfoxide Cobalt(II) perchlorate hydrates, 4051... 

Hydration of nitriles providing carboxamides is usually carried out m strongly basic or acidic aqueous media - these reactions require rather bars conditions and suffer from incomplete selectivity to the desired amide product. A few papers in the literature deal with the possibihty of transition metal catalysis of this reaction [28-30]. According to a recent report [30], acetonitrile can be hydrated into acetamide with water-soluble rhodium(I) complexes (such as the one obtained from [ RhCl(COD) 2] and TPPTS) under reasonably mild conditions with unprecedently high rate... 

Treatment of the bis(pyrazoyl)tetrazine (197) with an excess of hydrazine hydrate generates 3,6-bis(hydrazino)-l,2,4,5-tetrazine (208), a compound which might find use as an energetic additive in high performance propellants. Several salts of (208) have been reported, including the dinitrate and diperchlorate. 3,6-Dichloro-l,2,4,5-tetrazine (209), the product from treating (208) with chlorine in acetonitrile, reacts with the sodium salt of 5-aminotetrazole (210) to yield (211) (C4H4N14 - 79 % N). ... 

Simple molecular weight changes relative to the parent molecule may indicate the gain or loss of the equivalent of a methylene group (i.e. the loss of a methyl group replaced by a proton), oxidation, and hydration/dehydration or hydrolysis to list only a few possibihties. The formation of adduct ions, for example, sodium, potassium, or acetonitrile at +23, +39, and +43 Da, respectively, can provide the means for the preliminary identification of the molecular ion of a molecule. Isotope patterns, for example, from Cl, and even can also be diagnosti-... 

Temperature and pressure effects on rate constants for [Fe(phen)3] +/[Fe(phen)3] + electron transfer in water and in acetonitrile have yielded activation parameters AF was discussed in relation to possible nonadiabaticity and solvation contributions. Solvation effects on AF° for [Fe(diimine)3] " " " " half-cells, related diimine/cyanide ternary systems (diimine = phen, bipy), and also [Fe(CN)6] and Fe aq/Fe aq, have been assessed. Initial state-transition state analyses for base hydrolysis and for peroxodisulfate oxidation for [Fe(diimine)3] +, [Fe(tsb)2] ", [Fe(cage)] " " in DMSO-water mixtures suggest that base hydrolysis is generally controlled by hydroxide (de)hydration, but that in peroxodisulfate oxidation solvation changes for both reactants are significant in determining the overall reactivity pattern. ... 

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