Production Formaldehyde

A third possible route is to produce formaldehyde from methyla1 that is produced from methanol and formaldehyde (112,113). The incentive for such a process is twofold. Eirst, a higher concentrated formaldehyde product of 70% could be made by methyla1 oxidation as opposed to methanol... 

Fomialdehyde is a basic chemical budding block for the production of a wide range of chemicals finding a wide variety of end uses such as wood products, plastics, and coatings. Table 6 shows the distribution of formaldehyde production in the United States from 1966 through 1989 (115). Production percentages reported in the following discussion are for the United States. 

Table 6. U.S. Distribution of Formaldehyde Production According to Uses, 1966—1989 ...

BMSF Formaldehyde Product Bulletin, Hoechst-Celanese Corp., Dallas, Tex., June 1988. 

Formaldehyde Product Bulletin, Badische Anilin- und Soda-Fabrik AG, Ludwigshafen, Germany, Sept. 1975. 

Formaldehyde Product Bulletin, Deutsche Gold- und Silber-Scheideanstalt AG, Frankfurt, 1978. 

UF solutions are clear water solutions. They contain only very low molecular-weight, water-soluble UF reaction products plus unreacted urea. Various combinations of UF solutions are found. They contain a maximum of 55% unreacted urea with the remainder as one or more of methylolureas, methylolurea ethers, MDU, DMTU, or triazone, a cycHcal oligomer. AAPFCO has defined this class of compounds as urea—formaldehyde products (water- s oluble). 

Various processes can be employed to manufacture urea—formaldehyde products. They are generally categorized into two types, ie, dilute solution processes and concentrated solution processes. Table 3 Hsts select U.S. manufacturers of UF reaction products and their products. 

Because of the lack of solubility in the usual solvents, aniline-formaldehyde laminates are made by a pre-mix method. In this process the aniline hydrochloride-formaldehyde product is run into a bath of paper pulp rather than of caustic soda. Soda is then added to precipitate the resin on to the paper fibres. The pulp is then passed through a paper-making machine to give a paper with a 50% resin content. 

Disconnection oi (28) is by the methods described in the chapter so we shall explore the alternative (3p). Disconnection of amine (29) from (30) leaves (31) which is again a formaldehyde product. 

The iji vitro experiments, using the S-9 fraction from livers of uninduced Fisher 344 rats, was complicated by the fact that it became apparent that formaldehyde production was a poor measure of the extent of metabolism. The reason for that was that the S-9 fraction apparently catalyzed the oxidation of formaldehyde to formate. Consequently, determination of formaldehyde in an S-9 catalyzed reaction consistently gave low values of nitrosamine metabolism. Many workers use semicarbazide to suppress formaldehyde loss. We found, however, that semicarbazide is not a neutral bystander. 

The effluent generated during the production of the resins arises from different operations within the factory. The effluent of the production processes comes mainly from cleaning operations of reactors, storage tanks, filters from the towers of formaldehyde production, and the filters from the reactors. Another source for disposal comprises the spills occurring during the transfer of the resins from the reactors to the storage tanks and from these to the truck used to distribute them to other factories. 

Formaldehyde manufacture, 12 113-117. See also Formaldehyde production by exothermic reaction, 12 115 metal oxide catalyst, 12 115-117 methanol process for, 12 113 new processes for, 12 117 silver catalyst, 12 113-115 Formaldehyde plant... 

Dodge, M. C., Formaldehyde Production in Photochemical Smog As Predicted by Three State-of-the-Science Chemical Oxidant Mechanisms, J. Geophys. Res., 95, 3635-3648 (1990). 

The oxidation rate of methanol in SCW and the subsequent production and destruction of the primary intermediate, formaldehyde, has been investigated using Raman spectroscopy as an in situ analytical method. Effluent samples were also examined using gas chromatography. An elementary reaction mechanism, which reproduces accurately the quantitative features of methanol oxidation and formaldehyde production, is used to identify key rate controlling reactions during the induction period and the transition to the primary oxidation path (Rice et al., 1996). 

Dahl, A.R. Hadley, W.M. (1983) Formaldehyde production promoted by rat nasal cytochrome P-450-dependent monooxygenases with nasal decongestants, essences, solvents, air pollutants, nicotine, and cocaine as substrates. Toxicol, appl. Pharmacol., 67, 200-205... 

Kuykendall. J.R.. Trela. B.A. Bogdanffy, M.S. (1995) DNA-protein crosslink formation in rat nasal epithelial cells by hexamethylphosphoramide and its correlation with formaldehyde production. Mutat. Res., 343, 209-218... 

Viewing the data (Table X) as if it had been the usual assay of unknowns and subtracting the assay values after formaldehyde treatment from those before, the mixtures 1, 3, and 4 would apparently contain no flavonoid when in fact they contained 8.4 mg/liter GAE by separate assay. On the other hand, mixture 2 with 16.8 mg/liter GAE of flavonoid by separate assay gave 6.9 mg/liter by formaldehyde precipitation. If correction was made for 5.8 mg/liter GAE residual solubility of the catechin-formaldehyde product then mixures 1-4 would be indicated to have, respectively, 3.9, 12.7, 4.9, and 5.0 flavonoid and 39.6, 33.1, 41.3, and 38.4 mg/liter GAE nonflavonoid. These values are considered very close to the true content considering the results are based on differences between two assays with the attendant increase in variability. 

Formaldehyde production from natural gas is one of the most promising directions in modem chemical industry. However, the industrial realization of producing formaldehyde from methane is hampered by severe disadvantages, among which the most important are the low yields of the target product and multiple side reaction products. Therefore, the task in hand is the development of direct selective oxidation of methane to formaldehyde without formation of admixtures, which require additional thorough purification. 

Thus, a predominantly new means of formaldehyde production by direct methanol oxidation with hydrogen peroxide under homogeneous conditions without methanol formation stage was suggested. 

The concentration of H02 radicals in the system H202-H20-CH4 will be defined by the ratio of the rates of reactions (5.3) and (5.2). At the molar ratio CH4 H202 = 1 1, corresponding to optimal conditions of formaldehyde production,... 

In all cases, the degree of metabolism was estimated by monitoring both formaldehyde production and the concentration of unmetabolized alkaloid (39, 40). The related alkaloids 5, 6, and 7, which differ from corynantheidine only in configuration at C-3 and/or C-20, and the 9-methoxyl analogs 9-13,... 

The same phenomenon was observed for mitraciliatine (10) and the closed ring E alkaloids 14-19, where the percentage metabolism by O-demethylation estimated by formaldehyde production ( 1%) was much less than the degree of total metabolism (25-69%). Nevertheless, both hirsutine and mitraciliatine gave detectable amounts of a compound assumed by TLC analysis to be an 0-(17)-demethyl metabolite, whereas such was not the case with 14-19. Hirsutine and mitraciliatine were also metabolized (to unidentified products) by both rat and guinea pig liver microsomes, which did not metabolize alkaloids 4-6, 9, and 11-13. 

The largest and oldest chemical intermediate use for methanol is formaldehyde. Over half of the methanol currently consumed in the world goes into formaldehyde production. Formaldehyde is produced by the catalytic oxidation or the oxidative dehydrogenation of methanol The major outlet for formaldehyde is amino and phenolic resins. These resins are in turn used in the manufacture of adhesives for wood products, molding compounds, binders for thermal insulation and foundry resins. Formaldehyde is also consumed in the production of acetal resins, pentaerythritol, neopentyl glycol, trimethylolpropane, methylenediphenyldiisocyanate (MDI), and textile treating resins. 

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