Untersuchungen an wässerigen Formaldehydlösungen

Skell, P. S.; Suhr, Harald

doi:10.1002/cber.19610941220

Cited by 27 publications

(11 citation statements)

References 24 publications

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“…The acquisition parameters for the quantitative 13 C NMR measurements were as follows: acquisition time of 6 s, relaxation delay of 90 s, flip angle of 90°, and 64 scans or more. For the quantitative evaluation of 33 1947 n = 1 Landqvist 34 1955 n = 1 Skell and Suhr 35 1961 n ≥ 2 Gruen and McTigue 36 1963 n = 1 Ihashi et al 37 1965 n ≥ 2 Siling and Akselrod 11 1968 n = 1 Schecker and Schulz 38 1969 n = 1 Zavitsas et al 39 1970 n = 1 Bryant and Thompson 40 1971 n = 1 Koberstein et al 41 1971 n ≥ 2 Sutton and Downes 42 1972 n = 1 Fiala and Navratil 43 1974 n ≥ 2 Slonim et al 44 1975 n ≥ 1 Hahnenstein et al* 12 1994 n ≥ 2 Albert et al 6 1999 n ≥ 1 Winkelman et al* 13 2002 n = 1 Gaca et al 16 2014 n ≥ 2 Rivlin et al 14 2015 n ≥ 1 Formaldehyde + Methanol Hahnenstein et al* 12 1994 n ≥ 1 Hahnenstein et al* 15 1995 n = 1 Albert et al 7 2000 n ≥ 2 Balashov et al 17 2002 n ≥ 2 Gaca et al 16 2014 The data sets that were used in the present work are indicated by an asterisk (*). the NMR spectra, the same methods were applied as in previous works of our group.…”

Section: ■ Literature Datamentioning

confidence: 99%

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Kircher

Schmitz

Berje

et al. 2020

Ind. Eng. Chem. Res.

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Formaldehyde reacts with solvents that contain hydroxyl groups (R-OH) in oligomerization reactions to oxymethylene oligomers (R-(OCH 2 ) n -OH). The chemical equilibria of these reactions have been studied in the literature for water, for the mono-alcohols methanol, ethanol, and 1-butanol, as well as for the diols ethylene glycol and 1,4butynediol. In the present work, the collective data were analyzed. It was found that the prolongation of the oxymethylene chains by the addition of formaldehyde can be described very well with a generalized chemical equilibrium constant K R-OHx,n≥2 , which is independent of the substructure (R) of the solvent. This holds for the oligomerization reactions leading to R-(OCH 2 ) n -OH with n ≥ 2. The chemical equilibrium constantof the reaction of formaldehyde with the solvent R-OH depends on the solvent, but simple trends are observed. The hypotheses of the existence of a generalized chemical equilibrium constant K R-OH x,n≥2 was tested for the reactions of formaldehyde with ethanol and 1-propanol, for which neither K R-OHx,1 nor K R-OHx,n were previously available.The corresponding equilibria were studied by 13 C NMR spectroscopy and the equilibrium constants were determined. A novel method was developed and used in these studies to obtain data on K R-OHx,1 by NMR spectroscopy, which is difficult due to the low amount of molecular formaldehyde. It was found that the generalized equilibrium constant is even valid for the acid-catalyzed formation of poly(oxymethylene) dimethyl ethers (OME).

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Section: ■ Literature Datamentioning

confidence: 99%

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Kircher

Schmitz

Berje

et al. 2020

Ind. Eng. Chem. Res.

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“…spectroscopy over the techniques used previously for the investigation of such equilibria has been shown [6-91. Skell & Sukr [6] in an NMR. investigation found good agreement between their results and the earlier results of Azterbach & Barshall [lo] and those of Illiceto & Bezzi [ 2 ] .…”

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confidence: 99%

NMR.‐Investigation of the Formaldehyde Addition and Oligomerisation Equilibria in the System Formaldehyde/Water/Acetic Acid/Hydrochloric Acid

Gorrie

Raman

Rouette

et al. 1973

Helvetica Chimica Acta

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Summary. -An NMR. investigation of the state of formaldehyde in acidic solutions has been carried out. Solutions of DCl/D,O/CD,COOD containing two sources of formaldehyde, i. e. paraformaldehyde (I) and trioxane (TI), were used for this purpose. In systems I and I1 the effect of various D,O/CD,COOD ratios, at a constant DC1 concentration, was studied, while for I1 the effect of changing DC1 concentration was also investigated. The results show that in aqueous solution, formaldehyde exists primarily as the monomeric and linear oligomeric forms of methylene glycol. Reducing the amount of D,O (at constant DC1 concentration), while increasing the CD,COOD content, results in an increase in the polymeric species and in trioxane. I n addition, substitution of water by acetic acid results in systems that are catalytically more active than aqueous solutions of the same hydrochloric acid concentration. Along with the usual polymer-monomer equilibria which exist in such solutions, side reactions of methylene glycol with the hydrochloric acid present also occur to a small extent, e.g. acetylation, substitution of OH by C1 and the Cannizzaro reaction. It is suggested that these findings will result in a better understanding of the formaldehyde crosslinking reactions in cotton cellulose.

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“…Data on the distribution of formaldehyde in aqueous solution over the various kinds of polyoxyrnethylene are available from nuclear magnetic resonance spectroscopy studies by Koberstein et al (1971) and by Skell and Suhr (1961). In addition, it is known from measurements of the ultraviolet absorption in formaldehyde solutions (Walker, 1964, pp.…”

Section: Equilibrium Constants For the Chemical Reactionsmentioning

confidence: 98%

Vapor‐liquid equilibrium of formaldehyde‐and water‐containing multicomponent mixtures

Maurer¹

1986

AIChE Journal

120

176

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The vapor-liquid equilibria in the binary mixtures water-formaldehyde and methanol-formaldehyde are precisely correlated by introducing a physicochemical model that takes into account physical forces of interactions as well as chemical reactions. The most valuable feature of the model is its simple extension to multicomponent mixtures. From binary data alone the model is capable of accurately predicting vapor-liquid equilibria in complex mixtures such as formaldehyde-water-trioxane and formaldehyde-water-methanol. This is demonstrated by comparing calculated data with experimental results taken from the literature or measured in this work, at temperatures between about 310 and 400 K at pressures up to 500 kPa, and formaldehyde concentrations in the liquid phase of up to about 70 mol %. G. Maurer BASF AG Ludwigshafen, West Germany SCOPEFormaldehyde is an important raw material for the preparation of many products of the chemical industry-for example, plastics and adhesives-and is produced on a large scale. Because of its extremely high reactivity, formaldehyde is almost never prepared in the pure form, but is usually produced, stored, and processed further in the form of aqueous solutions.The marked tendency for reaction with other substances is a sizable obstacle to modeling the vaporliquid phase equilibrium in multicomponent aqueous formaldehyde solutions. While several methods to correlate the vapor-liquid phase equilibrium of the binary system formaldehyde-water have been described in the literature (Walker, 1964; Brandani et al., 1980; Kogan et al., 1977), there is virtually no method for modeling the vapor-liquid equilibrium in water-and formaldehyde-containing multicomponent mixtures with sufficient accuracy. The study presented here therefore refers to the development and testing of such a method. At first the binary system formaldehyde-water is considered, then the method is extended to ternary systems, the third component being either chemically inert-e.g., trioxane-or chemically reactive with formaldehyde as methanol. CONCLUSIONS AND SIGNIFICANCEDespite the appreciable industrial importance of such a mixture. Therefore a model was developed that, substances in addition to formaldehyde and water that by taking into account intermolecular forces between react with each other and contain inert or reactive comthe various types of molecules in the liquid phase as ponents, there is no reliable method available in the litwell as the most important chemical reactions, accuerature for describing the vapor-liquid equilibrium in rately predicts from information on binary systems alone, the vapor-liquid equilibrium in multicomponent formaldehyde and water-containing mixtures. The correlation starts from a model for the binaryThe present address of G. Maurer is Lehrstuhl fur Technische Thermcdynamik. Univcrsilat Kaiserslautcrn, Federal Republic of Germany. 932June 1986 Vol. 32, No. 6 AlChE Journal system formaldehyde-water. The equilibrium constants for the most important chemical reactions-e.g., the formation of m...

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Untersuchungen an wässerigen Formaldehydlösungen

Cited by 27 publications

References 24 publications

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

NMR.‐Investigation of the Formaldehyde Addition and Oligomerisation Equilibria in the System Formaldehyde/Water/Acetic Acid/Hydrochloric Acid

Vapor‐liquid equilibrium of formaldehyde‐and water‐containing multicomponent mixtures

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