Formic acid transfer

Ferrocenylphosphine-gold complexes, 225 Formaldehyde oligomerization, 332 Formic acid, transfer hydrogenation, 123 Formulas, chiral compounds, xiii-xvii Four-dimensional chemistty. See Asymmetric catalysis... 

Ethyl Formate (Acidity as Formic Acid) Transfer about 5 g of sample, accurately weighed, into a glass-stoppered flask containing a solution of 500 mg of potassium iodate and 2 g of potassium iodide in 50 mL of water. Titrate the liberated iodine with 0.1 A sodium thiosulfate, using starch TS as the indicator. Each milliliter of 0.1 N sodium thiosulfate is equivalent to 4.603 mg of CH2O2. 

If a phenol is not indicated, the solution may contain an aliphatic acid. Transfer to a distilling-flask, make definitely acid with dih H2SO4, and distil the volatile formic and acetic acids if present will distil over. If the distillation gives negative reactions, test the residual solution in the flask for oxalic, succinic, lactic, tartaric and citric acids and glycine, remembering that the solution is strongly acid. 

Ethyl formate. Reflux a mixture of 61 g. (50 ml.) of A.R. formic acid (98/100 per cent.) and 31 g. (39-5 ml.) of absolute ethyl alcohol for 24 hours. Transfer to a Claisen flask with fractionating side arm (or attach a fractionating column to the flask), distil and collect the liquid passing over below 62°. Wash the distillate with saturated sodium bicarbonate solution and saturate with salt before removing the ester layer. Dry with anhydrous sodium or magnesium sulphate, filter, and distil. The ethyl formate passes over at 53-54°. The yield is 36 g. 

The protected nucleoside-3-phosphoramidite monomer units such as 671 are used in the solid-phase oligonucleotide synthesis. In the 60mer synthesis, 104 allylic protective groups are removed in almost 100% overall yield by the single Pd-catalyze reaction with formic acid and BuNH2[432], N,(9-protection of uridine derivatives was carried out under pha.se-transfer conditions[433]. 

Acetals. Acetal resins (qv) are polymers of formaldehyde and are usually called polyoxymethylene [9002-81-7]. Acetal homopolymer was developed at Du Pont (8). The commercial development of acetal resins required a pure monomer. The monomer is rigorously purified to remove water, formic acid, metals, and methanol, which act as chain-transfer or reaction-terminating agents. The purified formaldehyde is polymerized to form the acetal homopolymer the polymer end groups are stabilized by reaction with acetic anhydride to form acetate end groups (9). 

That the reduction with formic acid proceeds by a hydride transfer reaction was proposed by Lukes and Ji2ba 100) and finally proven by Leonard and Sauers 63). The use of variously deuterated formic acid allowed Leonard and Sauers to determine that (1) protonation or... 

To 10 c.c. of the oil (otto of rose or rose-geranium oil) 10 c.c. of formic acid 100 per cent, (specific gravity 1 22) is added, and the mixture gently boiled under a reflux condenser for one hour. The mixture is cooled, 100 c.c. of water added, and the whole transferred to a separator. The aqueous layer is rejected, and the oil washed with successive quantities of water as in the acetylation process. The formylated oil is dried with anhydrous sodium sulphate, and about 2 grams neutralised and saponified with alcoholic potash in the usual manner. The percentage of citronellol is then calculated from the following formula —... 

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 macroscopic dielectric constant of liquid formic acid at 25° has the value 64, not much lower than that of water. Hence, from the simple electrostatic point of view, we should expect. /c for the proton transfer (211) carried out in formic acid solution, to have a value somewhat greater, but not much greater, than when the same proton transfer is carried out in water as solvent. In Table 12 we found that, in aqueous solution, the value of (./ + Jenv) rises from 0.3197 at 20°C to 0.3425 at 40°C. Measurements in formic acid at 25°C yielded for the equilibrium of (211) the value — kT log K = 4.70. Since for formic acid the number of moles in the b.q.s. is M = we find... 

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... 

The Urea Molecule. In Fig. 40 the vacant level of the CON2H4 molecule lies 0.085 electron-volt below the vacant level of the H2O molecule. If, when dissolved in formic acid, the vacant level of CON2H4 lies in a similar position relative to the vacant level of the H2O molecule in this solvent, it is clear that the tendency for protons to be transferred from the solvent, according to... 

A regioselective synthesis of 2-amino[l, 2,4]triazinones 708 was reported (82JHC1583 83JHC1671) by reaction of 706 with 0-(2,4-dinitrophenyl)-hydroxylamine 707 as an amino transfer agent. Subsequent reaction of 708 with ammonia or amines, followed by ring closure with formic acid, provided 709. 

When a photosynthetic organism is omitted, the addition of a photosensitizer is necessary. The methods use light energy to promote the transfer of an electron from a photosensitizer to NAD(P) via an electron transport reagent [6g]. Recently, carbon dioxide cvas reduced to formic acid with FDH from Saccharomyces cerevisiae in the presence of methylviologen (MV ) as a mediator, zinc tetrakis(4-methylpyridyl) porphyrin (ZnTMPyP) as a photosensitizer, and triethanolamine (TEOA) as a hydrogen source (Figure 8.8) [6h]. 

The electrophilic character of sulfur dioxide does not only enable addition to reactive nucleophiles, but also to electrons forming sulfur dioxide radical anions which possess the requirements of a captodative" stabilization (equation 83). This electron transfer occurs electrochemically or chemically under Leuckart-Wallach conditions (formic acid/tertiary amine - , by reduction of sulfur dioxide with l-benzyl-1,4-dihydronicotinamide or with Rongalite The radical anion behaves as an efficient nucleophile and affords the generation of sulfones with alkyl halides " and Michael-acceptor olefins (equations 84 and 85). 

Solutions of Moiseev s giant Pd colloids [49,161-166] were shown to catalyze a number of reactions in the quasi homogeneous phase, namely oxidative ace-toxylation reactions [162], the oxidative carbonylation of phenol to diphenyl carbonate [166], the hydrogen-transfer reduction of multiple bonds by formic acid [387], the... 

Pd Ketones, epoxides (hydrogen transfer from formic acid)... 

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