Formic acid, as solvent

Proton Transfers in Various Solvents. The Autoprotolysis of Methanol. Formic Acid as Solvent. The Sulfate Ion. Autoprotolysis of Formic Add. The Urea Molecule. Sulfuric Add and Liquid Ammonia as Solvents. 

Formic Acid as Solvent. In Tables 9 and 12 data were given for the proton transfer... 

The Sulfate Ion. In Fig. 36 we see that the vacant level of the (SO ) ion in aqueous solution lies only 0.13 electron-volt above the occupied level of HCOOH. If the interval has a comparable value when sulfate ions are present in formic acid as solvent, the thermal agitation should transfer a large number of protons from solvent HCOOH molecules to the (SO4)" ions. This was found to be the case when Na2SC>4 was dissolved in pure formic acid. Such a transfer of protons from molecules of a solvent to the anions of a salt is analogous to the hydrolysis of the salt in aqueous solution and is known as solvolysis, as mentioned in Sec. 76. In a 0.101-molal solution of Na2SC>4 in formic acid the degree of the solvolysis was found to be 35 per cent.1... 

Furthermore, since in Sec. 121 we found the value J = 0.36 electron-volt for the proton transfer (211), this gives the occupied proton level of the (HCOOII2)+ ion a position at (0.52 — 0.36) = 0.16 electron-volt above that of the (H30)+ ion in formic acid as solvent. This is shown in Fig. 65, where, for comparison, a diagram for proton levels in aqueous solution has been included, the level of the (H30)+ ion in aqueous solution being drawn opposite to the level of the same ion in formic acid solution. This choice is quite arbitrary, but was made in order to show more clearly that we may expect that one or more acids that are strong... 

To investigate thiamine metabolism in mammals, thiamine (Rf values 0.16, 0.04, and 0.03), urinary excretion of thiamine metabolites [thiochirome (Rf values 0.31, 0.28, and 0.33), thiazole (Rf values 0.85, 0.79, and 0.81), and 2-methyl-4-amino-pyrimidinecarboxylic acid (Rf values 0.42, 0.21, and 0.26)], and related compounds [pyrimidinesulfonic acid (Rf values 0.48, 0.39, and 0.46), a-hydroxyethylthiamine (Rf values 0.23, 0.09, and 0.06), A -methylnicotinamide (Rf values 0.31, 0.06, and 0.05)] were analyzed and identified by TLC on silica gel with acetonitrile-water (40 10 vol/vol) adjusted to a pH of 2.54, 4.03, and 7.85 with formic acid as solvents, respectively.Although A -methylnicotinamide and thio-chrome could not be separated in single-phase chromatography at pH 2.54, a second phase at right angle, with a pH 4.03 solvent, separated these quite clearly without affecting the resolution of the other compounds. 

Recently the halogenation of ascorbic acid in acidic media has been reported by Kiss and Berg (71) and independently by Pedersen and coworkers (72, 73). The treatment of ascorbic acid with halogen acids in acetic or formic acids as solvent affords 5-halo-5-acyloxy derivatives... 

Japanese chemists prepare the reagent either by the reaction of acetyl chloride with sodium formate or of formic acid with ketene. The reagent formylates amino acids in formic acid as solvent. The N-formyl group is useful as a blocking group in peptide synthesis. It is surprisingly resistant to basic hydrolysis but readily sol-volyzed in dilute acid. ... 

Phenols - sodium arylsulfonates. The S-aryl dimethylthiocarbamates [see formula (2), 2, 173] can also be oxidized to arylsulfonic acids, isolated as the sodium salts.6 Hydrogen peroxide is used as oxidant and formic acid as solvent. Yields are 55-64%. 

Film preparation. 10 wt% solutions of (see Scheme 1 for designation of sample names) MSE, MSEE, MST, ESE, MSE/MST blend, MSEE/MST blend and MSE/MSEE blend were prepared using formic acid as solvent. Chloroform solutions (10 wt%) of w-PrSE, /-PrSE, BSE or PeSE were also prepared. The polymer solutions were filtered using a pressure filter funnel with 10-15 micron pore size to remove any solid particles. 

CHT/MWNT composite nanofihres can be fabricated by electrospinning. In our experiments, different solvents, including acetic acid (1-90%), formic acid and trifluoroacetic acid (TFA)/dichloromethane (DCM) were tested for the electrospinning of CHT/CNT. No jet was seen when applying a high voltage (even above 25 kV), with 1-30% acetic acid and formic acid as solvent for the CHT/CNT nanocomposite. 

By observing the effect of an added weak base on the indicator ratio of a Hammett indicator during benzenesulfonic acid titration in formic acid as solvent, Hammett and Deyrup (172) estimated basic-... 

The titration by Hammett and Deyrup (172) of propionitrile with perchloric acid in formic acid as solvent gives a value for pK = —4.32 when corrected to the modern scale (272). This is in excellent agreement with a later value for acetonitrile determined in acetic acid (222). A much more recent titration of the same kind (181) supports the idea that acetonitrile is at least less basic than is diethyl ether and a good deal less basic than the amides. However, on the basis of several hydrogen-bonding studies one might conclude that acetonitrile is less basic than either anisole or acetophenone and that it has a pK close to —7.7 (150). 

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