The Reversible Hydration of Carbonyl Compounds

Bell, R. P.

doi:10.1016/s0065-3160(08)60351-2

Cited by 219 publications

(113 citation statements)

References 73 publications

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“…Contrary to the formic acid decomposition, no catalyst preactivation with base is needed for the pFA/FA decomposition. In water, it is known that FA is in principal solely present in the hydrated form as methanediol 34,35 . The equilibrium constant for methanediol/FA is K c ¼ 2 Â 10 3 in contrast to K c ¼ 2 Â 10 À 3 for 2,2-dihydroxypropane/ acetone 34,35 .…”

Section: Resultsmentioning

confidence: 99%

“…In water, it is known that FA is in principal solely present in the hydrated form as methanediol 34,35 . The equilibrium constant for methanediol/FA is K c ¼ 2 Â 10 3 in contrast to K c ¼ 2 Â 10 À 3 for 2,2-dihydroxypropane/ acetone 34,35 . Therefore, hydrated FA makes water accessible for dehydrogenation in aqueous solution, where methanediol acts as the hydrogen source.…”

Section: Resultsmentioning

confidence: 99%

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Selective and mild hydrogen production using water and formaldehyde

et al. 2014

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With the increased efforts in finding new energy storage systems for mobile and stationary applications, an intensively studied fuel molecule is dihydrogen owing to its energy content, and the possibility to store it in the form of hydridic and protic hydrogen, for example, in liquid organic hydrogen carriers. Here we show that water in the presence of paraformaldehyde or formaldehyde is suitable for molecular hydrogen storage, as these molecules form stable methanediol, which can be easily and selectively dehydrogenated forming hydrogen and carbon dioxide. In this system, both molecules are hydrogen sources, yielding a theoretical weight efficiency of 8.4% assuming one equivalent of water and one equivalent of formaldehyde. Thus it is potentially higher than formic acid (4.4 wt%), as even when technical aqueous formaldehyde (37 wt%) is used, the diluted methanediol solution has an efficiency of 5.0 wt%. The hydrogen can be efficiently generated in the presence of air using a ruthenium catalyst at low temperature.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Selective and mild hydrogen production using water and formaldehyde

et al. 2014

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“…In the case of HCHO the products are not well known. In the aqueous phase more than 99% of the HCHO is hydrated forming the gem-diol (CH 2 (OH) 2 ), which is much more soluble in water [38]. However, the absorption of radiation in the UV and visible range by the gem-diol form is negligible (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Small portions of the ice were ground with an electric mill and passed through a stainless steel test sieve (Retsch, Haan, Germany) with a mesh size of 0.5 mm. Afterwards, the snow was stored in 1 L Schott bottles covered with aluminum foil and sealed with traps filled with Hopcalite (Aero-Laser, Garmisch-Partenkirchen, Germany) to allow further degassing of nitrogen and to prevent the condensation of [21], HCHO measured at 20 • C (more than 99% present in the gem-diol form [38], the absorption coefficients are multiplied by 100), NO 3 − at 5 • C [20], and NO 2 − at room temperature [51].…”

Section: Experimental Methodsmentioning

confidence: 99%

Investigation of the photochemical decomposition of nitrate, hydrogen peroxide, and formaldehyde in artificial snow

Jacobi

Annor

Quansah

2006

Journal of Photochemistry and Photobiology A: Chemistry

109

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Species like nitrate (NO 3 − ), hydrogen peroxide (H 2 O 2 ), and formaldehyde (HCHO) are ubiquitous trace compounds in snow. Photochemical reactions of these compounds in the snow can have important implications for the composition of the atmospheric boundary layer in snow-covered regions and for the interpretation of concentration profiles in snow and ice regarding the composition of the past atmosphere. Therefore, we performed laboratory experiments to investigate such reactions in artificially produced snow samples. Artificial snow samples allow to execute experiments under defined and reproducible conditions and to investigate single reactions. All reactions were carried out under comparable experimental conditions and indicated that the photolysis of H 2 O 2 and NO 3 − occurred equally fast, while the photolysis of HCHO was considerably slower. Moreover, the photolysis of HCHO was only observed if initial concentrations were much higher than found in natural snow samples. These results indicate that the H 2 O 2 and NO 3 − reactions are possibly equally important in natural snow covers regarding the formation of OH radicals, while the photolysis of HCHO is probably negligible. Nitrite (NO 2 − ) was observed as one of the products of the NO 3 − photolysis; however, it was itself photolyzed at a higher rate than NO 3 − . After a certain photolysis period (≥8 h) the NO 3 − and NO 2 − concentrations in the snow remained constant at a level of 10% of the initial nitrogen content. This is probably due to a recycling of the anions from nitrogen oxides in the gas phase of the reaction cells indicating that the chemical reactions occur in or near the surface layer of the snow crystals.

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“…It is known that formaldehyde and acetaldehyde are relatively hydrated in aqueous solution (pK h (-log K h ) = -3.3 and -0.1, respectively) and that alkylaldehydes with a longer alkyl chain have a decreased tendency of hydration (pK h = 0.3 for butyraldehyde) [16]. Then the influence of hydration of dodecylaldehyde on the dissociation of C 12 S-QA seems to be minor.…”

Section: Dissociation Of C 12 S-qa In Weakly Basic Solutionmentioning

confidence: 99%

Alkylaldehyde–bisulfite adducts as cleavable surfactants

Itoh

Horiuchi

Takahashi

2007

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Alkylaldehyde-bisulfite adducts with octyl, decyl, and dodecyl groups (C n S: n=8,10,12) were synthesized and the surface-active properties of the water-soluble compounds were compared. Exchange of the counter anions of C 10 S and C 12 S from sodium to tetramethylammonium solubilized them in water. The latter ammonium salt (C 12 S-QA) had surface activities as good as a classical surfactant, sodium dodecylsulfate, and dissociated promptly in weakly basic solution at room temperature to be a non-surfactant. It was also found that C 12 S-QA solubilized a hydrophobic substrate (solid), N,N-dimethyl-3-nitroaniline, in water and then separated it as a precipitate after alkali treatment.

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The Reversible Hydration of Carbonyl Compounds

Cited by 219 publications

References 73 publications

Selective and mild hydrogen production using water and formaldehyde

Selective and mild hydrogen production using water and formaldehyde

Investigation of the photochemical decomposition of nitrate, hydrogen peroxide, and formaldehyde in artificial snow

Alkylaldehyde–bisulfite adducts as cleavable surfactants

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