79-14-1Relevant articles and documents
Gas Evolution Oscillators. 2. A Reexamination of Formic Acid Dehydration
Smith, Kenneth W.,Noyes, Richard M.,Bowers, Peter G.
, p. 1514 - 1519 (1983)
At formic acid concentrations of about 0.3 M in warm concentrated sulfuric acid, carbon monoxide is evolved smoothly whether the solution is stirred or not.If such a solution is rapidly stirred, decay of formic acid obeys clean irreversible first-order kinetics.If the solution is not stirred, the concentration of dissolved carbon monoxide rises to a limit of about 0.07 M; this value is about 80 times the equilibrium solubility at 1 atm.In an unstirred solution, the system approaches a "pseudoequilibrium" in which the concentrations of dissolved HCOOH and CO are about equal.If the concentration of formic acid is increased to about 4 M, gas is evolved from a gently stirred solution in oscillatory pulses.The amount of gas evolved during a pulse decreases with successive pulses, the maximum change in dissolved-gas concentration being approximately 0.07 M per pulse.These observations indicate that the oscillations result from repetitive release of supersaturation by homogeneous nucleation; they invalidate the purely chemical explanation developed by Showalter and Noyes.Supersaturations of up to 80-fold suggest that formic acid in concentrated sulfuric acid can generate carbon monoxide in situ at concentrations that could otherwise only be attained with high-pressure apparatus.
Glycolic acid formation in Chlorella.
WARBURG,KRIPPAHL
, (1960)
-
Facilitated series electrochemical hydrogenation of oxalic acid to glycolic acid using TiO2 nanotubes
Im, Sunmi,Park, Yiseul,Saad, Sarwar
, (2022/01/11)
In this study, the electrochemical reduction of oxalic acid (OX) was performed at electrodes made of TiO2 nanotubes (TNTs) in an aqueous medium under potentiostatic control in a two-compartment cell. The competing H2 evolution was almost non-existent at an applied potential of ?1.0 V vs Ag/AgCl. Thus, complete conversion of OX was achieved in high chemical (95%) and Faradaic (67%) yields. The selectivity of glycolic acid (GC) formation over that of glyoxylic acid (GO) is controlled by the length of the TNTs. A high selectivity (GC/GO ≈ 10) was obtained (glycolic acid/glyoxylic acid ≈ 10). The physical properties of the TNTs, such as length, uniformity, and mechanical strength, were controlled by varying the anodization time and the electrolyte composition.
PROCESSES FOR PREPARING ALDARIC, ALDONIC, AND URONIC ACIDS
-
Paragraph 0113-0116, (2021/05/29)
Various processes for preparing aldaric acids, aldonic acids, uronic acids, and/or lactone(s) thereof are described. For example, processes for preparing a C2-C7 aldaric acid and/or lactone(s) thereof by the catalytic oxidation of a C2-C7 aldonic acid and/or lactone(s) thereof and/or a C2-C7 aldose are described.
Oxidative Conversion of Glucose to Formic Acid as a Renewable Hydrogen Source Using an Abundant Solid Base Catalyst
Takagaki, Atsushi,Obata, Wataru,Ishihara, Tatsumi
, p. 954 - 959 (2021/07/14)
Formic acid is one of the most desirable liquid hydrogen carriers. The selective production of formic acid from monosaccharides in water under mild reaction conditions using solid catalysts was investigated. Calcium oxide, an abundant solid base catalyst available from seashell or limestone by thermal decomposition, was found to be the most active of the simple oxides tested, with formic acid yields of 50 % and 66 % from glucose and xylose, respectively, in 1.4 % H2O2 aqueous solution at 343 K for 30 min. The main reaction pathway is a sequential formation of formic acid from glucose by C?C bond cleavage involving aldehyde groups in the acyclic form. The reaction also involves base-catalyzed aldose-ketose isomerization and retroaldol reaction, resulting in the formation of fructose and trioses including glyceraldehyde and dihydroxyacetone. These intermediates were further decomposed into formic acid or glycolic acid. The catalytic activity remained unchanged for further reuse by a simple post-calcination.