CCCCLI.—The purification and some physical constants of formamide

Smith, Gilbert Freeman

doi:10.1039/jr9310003257

Cited by 19 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Early efforts to purify formamide to obtain reliable freezing and boiling points were fraught with problems yielding disparate results. 18,19 Formamide is very hygroscopic and rapidly picks up water. This is one of the main problems early researchers encountered in their attempts to obtain purified formamide.…”

Section: Properties Of Formamidementioning

confidence: 99%

“…Smith 19 in 1931 investigated the purification of formamide by freezing at 1 1C and used great care to avoid exposure to atmospheric water during the course of five successive freezing steps, especially during the removal of the water that remained at the top of the frozen formamide. The final formamide solution had a freezing point of 2.55 1C and a conductivity of 1 mmho.…”

Section: Properties Of Formamidementioning

confidence: 99%

See 1 more Smart Citation

Is formamide a geochemically plausible prebiotic solvent?

Bada

Chalmers

Cleaves

2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 °C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that ∼85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offering another possible route for prebiotic formamide production.

show abstract

Section: Properties Of Formamidementioning

confidence: 99%

Section: Properties Of Formamidementioning

confidence: 99%

Is formamide a geochemically plausible prebiotic solvent?

Bada

Chalmers

Cleaves

2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…The results for the sought primary standards pH PS are quoted in Table as a function of temperature for each buffer studied. Also quoted are some ancillary quantities that are essential for data processing and have been taken from the literature, namely, standard pd E ° 1 of cell 1, − densities, and relative permittivities of formamide. − …”

Section: Resultsmentioning

confidence: 99%

“…As shown by eq 17, E MAX need not be measured if the relevant mean molal activity coefficients γ can be calculated as a function of molality. This has been done, in the present case of 1:1-valent electrolyte within the above molality range, by use of the Debye−Hückel equation in the form where a 0 is the ion-size parameter, and for the calculation of the temperature-dependent constants A F and B F , the ancillary data of relative permittivity ε F and density ρ F are available from the literature. − On consideration of analogies of behavior existing between water and formamide, for the ion size parameter of each electrolyte MX, the same value generally used in water has been adopted. The related calculation of the transference number, t M + , based on the combined equations 15, 17, and 18, is rather insensitive to even conspicuous changes in a 0 .…”

Section: Resultsmentioning

confidence: 99%

Determination of Primary and Secondary Standards and Characterization of Appropriate Salt Bridges for pH Measurements in Formamide

Falciola

Mussini

et al. 2003

Anal. Chem.

View full text Add to dashboard Cite

For the first time, the standardization for pH measurements is here implemented in the domain of superpermittive media. The nonaqueous solvent studied is formamide (epsilon = 109.5 at 298.15 K) for which three primary standards and two secondary standards have been determined, whose excellent internal consistency has also been demonstrated by specific cell measurements. A comparison of the pH scale in formamide with the aqueous scale has been duly tried by accounting for the primary medium effect on the H+ ion. Furthermore, as a result of an ad hoc supplementary systematic investigation, three salt bridges of appropriate level of equitransference in formamide, that is, NH(4)Cl, NH(4)Br, and NH(4)I, have been characterized for abating the liquid junction potentials intervening in the pH-measuring cell to enable the user to carry out regular pH measurements and related controls.

show abstract

“…The effect of different halogen compounds is shown in Table III. Purification of Formamide Formamide can best be purified by high-vacuum distillation, followed by low-temperature crystallization out of contact with moist air (19).…”

Section: Reactionsmentioning

confidence: 99%

Formamide

Magill¹

1934

Ind. Eng. Chem.

View full text Add to dashboard Cite

CCCCLI.—The purification and some physical constants of formamide

Cited by 19 publications

References 0 publications

Is formamide a geochemically plausible prebiotic solvent?

Is formamide a geochemically plausible prebiotic solvent?

Determination of Primary and Secondary Standards and Characterization of Appropriate Salt Bridges for pH Measurements in Formamide

Formamide

Contact Info

Product

Resources

About