Formaldehyde yields

The reaction of urea with formaldehyde yields the following products, which are used as monomers in the preparation of urea formaldehyde resin. 

The most important commercial chemical reactions of phenol are condensation reactions. The condensation reaction between phenol and formaldehyde yields phenoHc resins whereas the condensation of phenol and acetone yields bisphenol A (2,2-bis-(4-hydroxyphenol)propane). PhenoHc resins and bisphenol A [80-05-7] account for more than two-thirds of U.S. phenol consumption (1). 

Methylphenol is converted to 6-/ f2 -butyl-2-methylphenol [2219-82-1] by alkylation with isobutylene under aluminum catalysis. A number of phenoHc anti-oxidants used to stabilize mbber and plastics against thermal oxidative degradation are based on this compound. The condensation of 6-/ f2 -butyl-2-methylphenol with formaldehyde yields 4,4 -methylenebis(2-methyl-6-/ f2 butylphenol) [96-65-17, reaction with sulfur dichloride yields 4,4 -thiobis(2-methyl-6-/ f2 butylphenol) [96-66-2] and reaction with methyl acrylate under base catalysis yields the corresponding hydrocinnamate. Transesterification of the hydrocinnamate with triethylene glycol yields triethylene glycol-bis[3-(3-/ f2 -butyl-5-methyl-4-hydroxyphenyl)propionate] [36443-68-2] (39). 2-Methylphenol is also a component of cresyHc acids, blends of phenol, cresols, and xylenols. CresyHc acids are used as solvents in a number of coating appHcations (see Table 3). 

Another significant use of 3-methylphenol is in the production of herbicides and insecticides. 2-/ f2 -Butyl-5-methylphenol is converted to the dinitro acetate derivative, 2-/ f2 -butyl-5-methyl-4,6-dinitrophenyl acetate [2487-01 -6] which is used as both a pre- and postemergent herbicide to control broad leaf weeds (42). Carbamate derivatives of 3-methylphenol based compounds are used as insecticides. The condensation of 3-methylphenol with formaldehyde yields a curable phenoHc resin. Since 3-methylphenol is trifunctional with respect to its reaction with formaldehyde, it is possible to form a thermosetting resin by the reaction of a prepolymer with paraformaldehyde or other suitable formaldehyde sources. 3-Methylphenol is also used in the production of fragrances and flavors. It is reduced with hydrogen under nickel catalysis and the corresponding esters are used as synthetic musk (see Table 3). 

Addition of sodium dithionite to formaldehyde yields the sodium salt of hydroxymethanesulfinic acid [79-25-4] H0CH2S02Na, which retains the useful reducing character of the sodium dithionite although somewhat attenuated in reactivity. The most important organic chemistry of sodium dithionite involves its use in reducing dyes, eg, anthraquinone vat dyes, sulfur dyes, and indigo, to their soluble leuco forms (see Dyes, anthraquinone). Dithionite can reduce various chromophores that are not reduced by sulfite. Dithionite can be used for the reduction of aldehydes and ketones to alcohols (348). Quantitative studies have been made of the reduction potential of dithionite as a function of pH and the concentration of other salts (349,350). 

DFT molecular dynamics simulations were used to investigate the kinetics of the chemical reactions that occur during the induction phase of acid-catalyzed polymerization of 205 [97JA7218]. These calculations support the experimental finding that the induction phase is characterized by the protolysis of 205 followed by a rapid decomposition into two formaldehyde molecules plus a methylenic carbocation (Scheme 135). For the second phase of the polymerization process, a reaction of the protonated 1,3,5-trioxane 208 with formaldehyde yielding 1,3,5,7-tetroxane 209 is discussed (Scheme 136). 

Korzeniewski C, Childers CL. 1998. Formaldehyde yields from methanol electrochemical oxidation on platinum. J Phys Chem B 102 489-492. 

Many of the nitronate salts of polynitroaliphatic compounds, particularly salts of gem-nitronitronates, exhibit properties similar to known primary explosives. Consequently, the storage of such salts is highly dangerous. Treatment of these nitronate salts with formaldehyde yields the corresponding methylol derivative via the Henry condensation. These methylol... 

Dimethylolnitramine (252) readily participates in Mannich condensation reactions treatment of a aqueous solution of (252) with methylamine, ethylenediamine and Knudsen s base (254) (generated from fresh solutions of ammonia and formaldehyde) yields (253), (255) and (239) (DPT) respectively. The cyclic ether (258) is formed from the careful dehydration of dimethylolnitramine (252) under vacuum. ... 

The cyclization of 128 (R = H) with formaldehyde gave the methylene-bridged bisoxazinones 135 [79ACH(101)61]. The corresponding A/-methyl derivatives (128, R = Me) and formaldehyde yielded the A-methyloxazi-nones 136 [84JCS(P1)2043]. 

Only formaldehyde yields a primary alcohol by reaction with a Grignard reagent. Figure 14-3 illustrates the reaction of ethylmagnesium bromide with formaldehyde to form 1-propanol. More-complicated alcohols, such as cyclopentylmethanol, can be synthesized by this means (as shown in Figure 144). 

Reaction with formaldehyde yields glycolic nitrile (a cyanohydrin), but in... 

Colors and intensity of bands may differ after formaldehyde fixation compared with those obtained by glutaraldehyde fixation. Formaldehyde yields blackish and glutaraldehyde gives brownish bands. 

In recent years, it has been shown that co-ordinated phosphines may also undergo reactions with carbonyl compounds. This is well exemplified in the reactions of [(MeHPCH2CH2PHMe)2Pd]2+ (Fig. 5-51). The reaction with formaldehyde yields a complex of an open-chain hydroxymethyl substituted ligand, the same species that is obtained from reaction of the free ligand. This is the phosphorus analogue of the aminol intermediate in imine formation. It is extremely unusual to obtain RP=CR2 systems in the absence of sterically demanding substituents. 

In each part of this problem in which there is a change in the carbon skeleton, disconnect the phenyl group of the product to reveal the aldehyde or ketone precursor that reacts with the Grignard reagent derived from bromobenzene. Recall that reaction of a Grignard reagent with formaldehyde (H2C=0) yields a primary alcohol, reaction with an aldehyde (other than formaldehyde) yields a secondary alcohol, and reaction with a ketone yields a tertiary alcohol. 

Figure 4.10 shows temperature influence on the process results formaldehyde yield reaches its maximum (about 40%) with temperature raise to 520 °C and total methane conversion increase. Above 520 °C, CO and C02 are detected in reaction products. Their formation rates noticeably increase with temperature. The occurrence of these compounds in the system is explained by sequential formaldehyde transformation to intense degradation products in the high temperature range. After-oxidation of methanol synthesized in the system also contributes to formation of these products. 

The results of experiments on the contact time effect on methane oxidation reaction (Figure 4.11) show that formaldehyde yield increases to some extent (39%) with the contact time. Maximal yield of formaldehyde is reached at r = 1.2 s, which is optimal for execution of the reaction at selected parameters. As the contact time exceeds 1.2 s, side products occur in the system CO, C02 and CH3OH concentration of the last compound reaches its maximum at r = 1.4 h. The above results show that methane is oxidized to formaldehyde... 

Experiments determining temperature dependence of methanol oxidation with hydrogen peroxide were carried out under the same conditions. Figure 4.13 shows methanol conversion and formaldehyde yield (10%) maxima at 590 °C. A further increase of temperature decreases formaldehyde content in the reaction mixture. This testifies to the process proceeding by the consecutive scheme with further transformation of formaldehyde, CO and C02 concentration increasing simultaneously. 

Thus, the decrease of formaldehyde yield with increasing temperature after reaching the yield maximum is explained by an increase of CO concentration in the products of its conversion. C02 yield is greater than CO yield, hence, in low temperature ranges its amount increases proportionally with temperature, but at 600 °C the formation rate is stabilized. At high temperatures (600-620 °C) the amount of C02 remains constant, and above 620 °C C02 yield may be reduced. As a consequence, C02 is mostly formed at severe oxidation of methanol, but not from CO, because in that case CO concentration increase in the contact zone would increase C02 yield at 610-620 °C. 

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