Formaldehyde In Aqueous Solution Research Articles

Selective Formation of 2-Hydroxy-3,3-bis(hydroxymethyl)-γ-butyrolactone from Formaldehyde on Hydrotalcite-Type Catalysts

Abstract As a model for prebiotic sugar formation under neutral to acidic conditions, reactions of formaldehyde over hydrotalcite-type catalysts were investigated. Heating an aqueous solution of formaldehyde at 140—200 °C for 12 h over Ni–Fe hydrotalcite-type catalyst afforded 2-hydroxy-3,3-bis(hydroxymethyl)-γ-butyrolactone selectively, a 5.8% yield based on gas–liquid chromatographic analysis. The structure was identified by 1H and 13C NMR and 1H–13C HSQC, HMBC and 13C–13C 2D INADEQUATE NMR experiments.

Preparation and properties of phenolated wood/phenol/formaldehyde cocondensed resin

AbstractA phenolated wood/phenol/formaldehyde cocondensed novolac‐type resin was prepared with a two‐stage procedure. Wood was first liquefied in the presence of phenol by using an acid catalyst to produce a phenolated wood, and after the liquefaction, formalin (i.e., formaldehyde aqueous solution) was added to conduct a cocondensation reaction for converting the remaining nonreacted phenol into resin components. It was found that this procedure can convert almost all the phenol remained after liquefaction into resin, and therefore significantly upgrades the practical value of the liquefaction technique. In addition, it can also greatly improve the thermofluidities of the phenolated wood resins and the mechanical properties of their molded products. As a result, the flow temperatures and melt viscosities of the cocondensed resins were much lower than those of the phenolated wood resins. However, these two properties were more or less similar to those of the conventional novolac resin, resulting in an excellent processability. The flexural properties of the molded products made from the cocondensed resins were much higher than those of the phenolated wood and also somewhat superior to those of the conventional novolac resin. Therefore, this preparation procedure is a prospective technique for preparing wood‐based novolac resins. © 1995 John Wiley & Sons, Inc.

Biological indicators for low temperature steam and formaldehyde sterilization: the effect of defined media on sporulation, growth index and formaldehyde resistance of spores of Bacillus stearothermophilus strains

Preliminary screening was carried out on spores of 29 strains of Bacillus stearothermophilus to determine their potential as biological indicator organisms for low temperature steam and formaldehyde sterilization. Each strain was sporulated on four chemically defined media. Fourteen strains produced satisfactory sporulation on one or more of the media but there was considerable variation in the extent of sporulation. The growth index of the spores, which was dependent on both the strain of organism and the sporulation medium, ranged from 1% to 90%. The spores were appraised on the basis of their resistance to inactivation by 0.5% w/v formaldehyde in aqueous solution at 70 degrees C. The survivor curves obtained could be characterized into five types on the basis of the shape of the curve. Only five strains of Bacillus stearothermophilus produced spores with the characteristics of high resistance, linear semi-logarithmic survivor curve and high growth index that would be required of a potential biological indicator organism.

In situ degradation of formaldehyde with electrogenerated hypochlorite ion

The oxidant ClO− was generated on an SPR (SnO2-PdO-RuO2-TiO2) anode and used to degrade formaldehyde in aqueous solution. The current efficiency of the production of hypochlorite ion was significantly affected by the concentration of chloride ion, pH and stirring rate. The effect of current density and temperature on the current efficiency for electrogeneration of hypochlorite ion was slight. The maximum anodic current efficiency was 99.3% when 100 C was charged. Increasing the concentration of chloride ion, pH, temperature, stirring rate and the concentration of formaldehyde in the solution and decreasing the current density and charge passed resulted in increased current efficiency of degradation of formaldehye with electrogenerated hypochlorite ion.

Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution: II. Polycondensations

We have prepared a [32P]-labeled oligonucleotide probe carrying a ureido (-NH-CO-NH2) function at its 3'-terminus. This labeled oligomer was used to study polycondensations of urea and formaldehyde and of various phenols and formaldehyde in aqueous solution. The formation of formaldehyde copolymers attached to the amido-function of the probe was monitored by gel electrophoresis. Our results are generally in agreement with those obtained using conventional techniques. Our method is suitable for monitoring potentially prebiotic polycondensation reactions involving formaldehyde.

Potentiometric determination of aminal stability constants

Potentiometric titration was used to determine the logarithms of the stepwise equilibrium constants for the species formed between morpholine and formaldehyde in aqueous solution, ionic strength 0.5 and 2.5 M (KCl) at 25°C. The instrumental and computational techniques developed for metal-ligand stability constant determination were applied. Formaldehyde is equivalent to the metal-ion and is represented by M while neutral morpholine is equivalent to the ligand and is represented by L. The stability constants of the following equilibria were determined by non-linear regression (figures in parentheses are at ionic strength 2.5 M KCl): M + L ⇆ ML (hemi-aminal) log K 1 = 2.90 ± 0.02 (2.980 ± 0.004); ML + L ⇆ ML 2 (bis-aminal); log K 2 = 1.3 ± 0.2 (1.41 ± 0.07); MLH ⇆ ML + H + (protonated hemi-aminal) p K a = 5.87 ± 0.01 (6.411 ± 0.005); ML 2H ⇆ ML 2 + H + (protonated bis-aminal) p K a = (7.6 ± 0.2). the p K a of the protonated bis-aminal could only be determined at the higher ionic strength. The results are in good agreement with reported values determined using the classic formol titration. The automated titration system acquired the full time course of the pH change upon each titrant addition allowing a kinetic analysis to be performed as well as an equilibrium analysis. The forward and reverse rate constants for M + L ⇆ ML were 0.77 M −1 sec −1 and 8.1 × 10 −4 sec −1. respectively.

Fluorescent Spot Test Method for Specific Detection of β-Lactamases

A simple, sensitive fluorescent spot test method for specific detection of microbial beta-lactamases has been developed, based on the modification of a previously disclosed method (K. C. S. Chen, October 23, 1990, U.S. Patent 4,965,193). The new fluorescence developer used in the present study consisted of 0.5 mM HgCl 2, in 0.5 M sodium citrate buffer, pH 4.5, prepared in 0.5% formaldehyde aqueous solution. A β-lactam substrate solution consisting of a β-lactam antibiotic with an acyl side chain containing an α-amino group and an α-phenyl group, or its derivatives, was incubated with a β-lactamase-producing organism. One volume of the fluorescence developer was added to 4 vol of the incubated β-lactam substrate solution, followed by heating the mixture at 45°C for 10 min. The mixture was spotted on filter paper. Production of fluorophore indicated β-lactamase activity. Each fluorophore was analyzed by TLC and its chemical identity was determined. Using ampicillin as the penicillinase substrate and cephalexin as the cephalosporinase substrate, the new method can be conveniently carried out by using dropping bottles for storing and dispensing the substrate solutions and the fluorescence developer. This modified method also provided more favorable conditions for the penicillinases to remain active during fluorescence development. Therefore, the sensitivity of the test was increased.

Development of a new advanced process for manufacturing polyacetal resins. Part I. Development of a new process for manufacturing highly concentrated aqueous formaldehyde solution by methylal oxidation

AbstractA new technology for the production of highly concentrated aqueous formaldehyde was developed by oxidizing methylal. Whereas the oxidation of methanol yields 1 mol of water per 1 mol of formaldehyde, methylal oxidation produces only 1 mol of water for every 3 mol of formaldehyde. Thus, the output from methylal oxidation is more than 70% formaldehyde compared with 55% from methanol oxidation. For this purpose, basic research for methylal synthesis was tried and the world's first commercial production of methylal was accomplished. Using this methylal, the world's first technology of methylal oxidation for manufacturing highly concentrated aqueous formaldehyde was established by development of a new methylal oxidation catalyst composed of iron, molybdenum, and a third component. This highly concentrated aqueous formaldehyde is then fed to the acetal homopolymer and copolymer plant whose combined capacity is 35,000 tons/years. © 1993 John Wiley & Sons, Inc.

Simultaneous absorption and desorption with reversible first-order chemical reaction: analytical solution and negative enhancement factors

The problem of gas absorption accompanied by a first-order reversible reaction, producing a volatile reaction product, is considered. A general analytical solution is developed for the film model, resulting in explicit relations for the concentration profiles in the film and for the mass transfer enhancement factors. The solution is not restricted to equal diffusivities, and is also applicable to the simultaneous absorption and reversible reaction of two gases. Several limiting cases are derived. It is shown that enhancement factors are possible with values larger than one, but also smaller than one, and even negative. The latter occur in the industrially important absorption of formaldehyde in aqueous solution.

Pulmonary Cytochrome P450 in Rats Exposed to Formaldehyde Vapor

The lungs of rats exposed to formaldehyde vapor, for 6 hr/day over 4 consecutive days, were examined for signs of injury and for changes in the level, or activity, of cytochrome P450. The animals were supplied with 10 ppm formaldehyde vapor generated, in two separate experiments, either from an aqueous solution of formaldehyde or from heated paraformaldehyde. All rats were exposed for 6 hr, on each of 4 consecutive days, and killed I day after the onset of the fourth period of exposure. The lung weights and gains in body weight of exposed animals were indistinguishable from those of their controls. Lungs from the formaldehyde-exposed animals did not show any signs of injury, even at the ultrastructural level. Bronchoalveolar lavage samples from exposed animals showed no increase in alkaline phosphatase or γ-glutamyl transpeptidase activity. The total concentration of cytochrome P450 in the lungs of exposed animals was similar to that found in their controls. The P450 activity of pulmonary microsomes from exposed animals was not significantly different from that obtained with samples from the control animals. These results indicate that repeated exposure to 10 ppm formaldehyde vapor does not injure the deep lung of rats and has no effect on the level of lung P450 or on its activity against substrates for the most common pulmonary forms of this enzyme.

Enthalpy change on vaporization of aqueous and methanolic formaldehyde solutions

AbstractA physicochemical model for vapor‐liquid equilibrium in multicomponent formaldehyde‐containing mixtures (Maurer, 1986; Hasse et al., 1990; Hasse and Maurer, 1991a). is extended to describe enthalpy changes upon vaporization. Predicted enthalpy changes are compared with new experimental results. The measurements were carried out with a thin‐film evaporator flow‐calorimeter (Liu and Maurer, 1991). More than 80 experimental data points for mixtures of formaldehyde + water and formaldehyde + methanol + (small amounts of water) are reported. The data cover the temperature range from 323 to 363 K (formaldehyde + water) and 312 to 347 K (formaldehyde + methanol) at liquid phase formaldehyde mole fractions up to about 0.3 (formaldehyde + water) and 0.6 (formaldehyde + methanol). Comparisons between predicted and experimental results for the enthalpy change reveal deviations of only a few percent. Further improvements are achieved by fitting some model parameters, which originally were estimated from noncalorimetric data.

Asymmetric Synthesis via Heterocyclic Intermediates, XLVIII. Asymmetric Synthesis of Diastereomerically and Enantiomerically Pure, 3-Substituted (2S,3R)-N-Methylserine Esters

N-Methyl amino acids deserve special attention as biologically active species[*] and for the preparation of peptide analogues[31. These peptide analogues are of increasing interest for obtaining information about the backbone conformation of pep tide^[^! Only a few satisfactory methods are currently available for the N-methylation of amidesr5’, Nacyl amino acidsL6] and their imine-type derivatives[’], but no general method has been reported for the N-methylation of serine esters until now. In 1976 Weinreb and co-workers[’] showed that simple amides can be N-methylated by reduction of their methylol derivatives with triethylsilane/trifluoroacetic acid. In 1983 this method was employed by Freidinger and co-workers[6b1 for the N-alkylation of Fmoc-protected amino acids via their oxazolidinone derivatives. In 1987 Grieco and Bahsas[*’ reported on a two-step sequence for the N-methylation of amino acids and peptides compatible with unprotected phenols and hydroxy compounds. The iminium ion generated in situ from the amino acid and aqueous formaldehyde solution undergoes an aza Diels-Alder reaction with cyclopentadiene to give the corresponding 2-azanorbornene derivative. The iminium-ion species, generated during an acid-catalyzed retro aza Diels-Alder reaction, can be reduced with triethylsilane to provide the Nmethyl amino acid in a total yield of 54-86%.

Heat of Dilution in Aqueous and Methanolic Formaldehyde Solutions

As part of an ongoing project dealing with thermodynamic properties of formaldehyde containing fluid mixtures, heats of dilution of formaldehyde, water, methanol and trioxane containing mixtures have been measured in a heat flow calorimeter at temperatures between 298 and 363 K. New mixing cells, allowing pressurization and avoiding vapor-space, were used to take over 300 data points covering binary, ternary and quarternary mixtures. The observed heats of dilution are generally small (less than 250 J/mol). They are correlated using a physico-chemical model. Physical effects are considered by the UNIFAC-group contribution method, reaction enthalpies are used for the description of the chemical contributions. The model allows a good representation of most of the binary data, extrapolations to multicomponent systems using binary data alone are, however, only qualitatively correct.

Radiolysis of aqueous formaldehyde relevant to cometary environments

The radiation chemistry of aqueous solutions of formaldehyde was studied in order to obtain an insight into the possible role of ionizing radiation on cometary environments. Aqueous solutions of 1.0 mol dm −3 formaldehyde were exposed to γ-radiation in the dose rage from 0.01 to 1200 kGy at 298 K. The radiation chemical yield of decomposition of formaldehyde was determined to be: G(−CH 2(OH) 2) = 26.3±1.2. The high radiation chemical yield of decomposition was explained by a chain reaction initiated by the radical ·CH(OH) 2 with formaldehyde. Computer fitting of the experimental data gives k(·CH(OH) 2 + CH 2(OH) 2) = 8.0×10 1 dm 3 mol −1 s −1. In the computer treatment of experimental findings we used 54 equations to consider the radiolysis of water and 11 reactions for the radiolysis of aqueous formaldehyde. Based on previous estimates of the total dose of ionizing radiation that comets have accumulated over 4.6 billion years, we predict a radiation damage-depth curve of formaldehyde in comet nuclei.

Preparation of platinum on activated carbon

In a study of the preparation of Pt/C catalysts, a set of modified activated carbon carriers has been prepared by nitric acid or air oxidation, or thermal decarboxylation. The carbons obtained by these methods had largely identical pore structures, but differed considerably in surface chemistry. A series of activated carbons with different surface chemistry was impregnated with aqueous hydrochloroplatinic acid solutions. Upon impregnation, the carbon reduced a certain amount of the Pt IV complex to Pt II, which was strongly chemisorbed at the walls of the carrier's mesopores. Weak physisorption was also observed. The capacity of the carrier for the reductive chemisorption was governed by its surface chemistry, and thus was strongly dependent on the pretreatment of the activated carbon. Aqueous alkaline formaldehyde solutions were then applied as reductor. After a period of slow growth, during which small zero-valent platinum particles were formed, a critical crystallite size was reached. Subsequently, a fast autocatalytic growth was observed until the supply of unreduced platinum became rate limiting. During the reduction process the carrier surface chemistry was (slightly) modified. After the reduction was completed, a catalytic autoredox reaction of excess formaldehyde to methanol and formate was observed. By properly selecting the preparation conditions, platinum-on-carbon catalysts combining a high metal load (5%) and a high metal dispersion (60%) could be obtained.

Electrochemical hydrodimerization of formaldehyde to ethylene glycol

The electrohydrodimerization of formaldehyde proceeds in close to quantitative yield and current efficiency to give ethylene glycol. The optimum process conditions require an aqueous formaldehyde solution of high concentration, a pH range of about 5 to 8, the presence of a quaternary ammonium salt, and reaction temperatures in excess of about 80°C. Remarkably, the process only works well at graphite, at which the enzyme-like specificity is believed to be related to the carbon surface oxide structure.

Experimental and computational study of the radiation-induced decomposition of formaldehyde. Implications to cometary nuclei

The radiation-induced decomposition of aqueous solutions of formaldehyde was studied at 298 and 77 K in order to obtain an insight into the possible role of ionizing radiation on cometary chemistry. Aqueous solutions of 1.0 mol dm−3 formaldehyde were exposed to γ-radiation in the dose range from 0.01 kGy to 1.2 MGy. The radiation chemical yield of decomposition of formaldehyde was determined to be: G(−CH2(OH)2)=26.3±1.2 at 298 K and G≤0.48 at 77 K.

Synthesis and radical polymerization of ethyl α‐acetoacetoxymethylacrylate

AbstractEthyl α‐acetoacetoxymethylacrylate (1) was prepared by reaction of diketene and ethyl α‐hydroxymethylacrylate which was obtained from the reaction of triethyl phosphonoacetate and an aqueous solution of formaldehyde. 1 contains 27% of the enol tautomer. The polymerization of 1 in benzene initiated with dimethyl 2,2′‐azoisobutyrate (2) was investigated kinetically. The overall activation energy of polymerization was determined to be 84,8 kJ/mol. The polymerization rate (Rp) at 50°C is expressed by Rp = k[2]0,5 [1]1,1. From an electron spin resonance study, the polymerization system was revealed to involve persistent propagating poly(1) radicals. The rate constants of propagation and termination were estimated to be kp = 300 and kt = 1,0 · 106 1 · mol− · s− at 60°C, respectively, using the polymer radical concentration and assuming stationary state conditions. Copolymerization of 1 (M1) and styrene (M2) was examined at 50°C, and the following copolymerization parameters were obtained; r1 = 0,28, r2 = 0,22, Q1 = 1,2, and e1 = +0,87.

Synthesis of [14C]-pargyline {N-methyl-N-([1-14C]-propargyl)benzylamine} with the radioactive label on the propargyl group

A one-pot reaction scheme leading to 14C-labeled pargyline (N-methyl-N- propargylbenzylamine) where in the radioactive label from [14C]-formaldehyde is synthetically incorporated into the methylene group of the propargyl side chain is described. Thus, [14C]-formaldehyde (aqueous solution) is condensed in solvent dioxane with N-methyl-benzylamine and mono-trimethylsilylacetylene in the presence of cupric acetate dihydrate at elevated temperatures (85–86°) for 24 hrs. The Mannich condensation product is then desilylated and the radiolabeled pargyline is purified by partitioning in ether from acid and base followed by flash chromatography, and isolated as the hydrochloride. The radioactive yield is 58%. This method should be generally applicable for the incorporation of radioactive label into the propargyl methylene group of other drugs containing a propargyl side chain.

Symptoms, signs and yield reduction associated with Rhizoctonia disease of potato induced by tuberborne inoculum ofRhizoctonia solani AG-3

The disease inducing potential of tuberborne inoculum ofRhizoctonia solani AG-3 on potato was evaluated. Four cultivars of potato, with or without visible evidence of tuberborne inoculum and with or without formaldehyde treatment, were planted in the field. Total and US #1 yields were reduced by an average of 19.2% and 35.1% respectively on those plots from seed tubers with tuberborne inoculum and plots from seed tubers that received no formaldehyde treatment. Tuberborne inoculum delayed emergence by 23.9%, and large girdling lesions appeared on the subterranean stems of more than 90% of the plants produced from contaminated seed. A high incidence of aerial stem lesions and hymenial development also was associated with tuberborne inoculum. However, the number of stems per plant did not differ significantly among treatments. A two min dip in 1.85% aqueous solution of formaldehyde killed most if not all of the seedborne inoculum.