Paraformaldehyde Phenol

Paraformaldehyde, formaldehyde, phenol polymer Paraformaldehyde, phenol polymer. See Phenol-formaldehyde resin Paraformaldehyde/urea polymer Paraformaldehyde/urea resin. See Urea-formaldehyde resin... 

Synonyms Formaldehyde, phenol polymer Formaldehyde, polymer with paraformaldehyde and phenol Paraformaldehyde, formaldehyde, phenol polymer Paraformaldehyde, phenol polymer Phenol-formaldehyde copolymer Phenol, formaldehyde polymer Phenol, polymer with formaldehyde Phenol, polymer with paraformaldehyde Classification Thermosetting polymer Definition Reaction prod, of phenol with aq. 37-50% formaldehyde with basic catalyst chief class of phenolic resin Formula (CeHeO (CH20)x)x Properties Gray to bik., hard, infusible solid when cured resist, to moisture, soivs., heat to 200 C dimensionally stable good elec, resist. noncombustible... 

Synonyms P-F-R-2 resol phenol formaldehyde resin phenol formaldehyde phenol polymer with formaldehyde formaldehyde-pnenol polymer paraformaldehyde-formaldehyde-phenol polymer paraformaldehyde-phenol polymer phenol-formaldehyde polymer Novolac Resole resol based on phenol, resorcinol, and formaldehyde... 

Paraformaldehyde is used by resin manufacturers seeking low water content or more favorable control of reaction rates. It is often used in making phenol—, urea—, resorcinol—, and melamine—formaldehyde resins. 

Various phenols can be selectively hydroxymethylated at the ortho position by heating with paraformaldehyde and phenylboronic acid. 

Zavitsas et al. account for the effects of water in their calculations. Water promotes depolymerization of the paraformaldehyde as well as the hemiformals. Their modifications correct for the apparent reduction in methylolation rate as the extent of reaction proceeds, in that the hemiformals remove formaldehyde reactivity from the reaction mixture. Their rate constants look large because they are written for phenate concentrations rather than phenol and because of the formaldehyde equilibrium adjustments. They note that unsalted phenol is a by-... 

Possible formaldehyde crosslinkers are paraformaldehyde [16,17,144,145], methylolurea mixtures such as urea-formaldehyde precondensate or formurea [145], or urea and phenol methylols with longer chains to overcome steric hindrance. 

A biopolymer produced by a particular strain of bacteria is becoming widely used as a substitute for clay in low-solids muds. Since the polymer is attacked readily by bacteria, a bactericide such as paraformaldehyde or a chlorinated phenol also must be used with the biopolymer. The system has more stable properties than the extended bentonite system, because biopolymer exhibits good rheological properties in its own right, and has a better tolerance to salt and calcium. The system can be formulated to include salt, such as potassium chloride. Such a system, however, would then be classed as a nondispersed inhibitive fluid. 

Water is necessary for decomposing paraformaldehyde to formaldehyde (Fig. 7.4). However, water can serve as an ion sink and water-phenol mixtures... 

Alkyl-substituted phenols have different reactivities than phenol toward reaction with formaldehyde. Relative reactivities determined by monitoring the disappearance of formaldehyde in phenol-paraformaldehyde reactions (Table 7.3) show that, under basic conditions, meta-cresol reacts with formaldehyde approximately three times faster titan phenol while ortho- and para-cresols react at approximately one-third the rate of phenol.18 Similar trends were observed for the reactivities of acid-catalyzed phenolic monomers with formaldehyde. 

Linear novolac resins prepared by reacting para-alkylphenols with paraformaldehyde are of interest for adhesive tackifiers. As expected for step-growth polymerization, the molecular weights and viscosities of such oligomers prepared in one exemplary study increased as the ratio of formaldehyde to para-nonylphenol was increased from 0.32 to 1.00.21 As is usually the case, however, these reactions were not carried out to full conversion, and the measured Mn of an oligomer prepared with an equimolar phenol-to-formaldehyde ratio was 1400 g/mol. Plots of apparent shear viscosity versus shear rate of these p-nonylphenol novolac resins showed non-Newtonian rheological behavior. 

An alternative preparation of benzofurans was carried out via a microwave-assisted Mannich condensation of paraformaldehyde and a secondary amine followed by cyclization with an alkynyl phenol 185 mediated by alumina doped with Cul (Scheme 67). The reaction can be carried out in a single-step... 

Various phenols can be selectively hydroxymethylated at the ortho position by heating with paraformaldehyde and phenylboronic acid. An intermediate 18-1 having the formula C14H1302B for the case shown can be isolated prior to the oxidation. Suggest a structure for the intermediate and comment on its role in the reaction. 

The development of a solvent reaction between triphenyl borate and paraformaldehyde to produce a boron-modified phenolic resin that flowed at usual processing temperatures has been reported.90... 

Ullmann and Fetvadjian reported the modification which made the synthesis more generally useful, when they heated together equimolar amounts of an aromatic amine and a phenol with paraformaldehyde or with benzaldehyde, thus making it possible to obtain unsymmetrical acridines (03CB1027). Thus, from 2-naphthol and 1-naphthylamine they obtained dibenzo[c,/]acridine (613), and from 2-naphthol and 2-naphthylamine dibenzo[c,fi]acridine (614). In a similar manner, from 1-aminoacridine and the two naph-thols are obtained the benzo [a]- and benzo[c]-naphtho[2,3-fi]acridines (615) and (616), and from 2-aminoacridine and the naphthols the benzo[a]- and benzo[c]-naphtho[2,3-/]acridines (617) and (618) (69JCS(C)1337). The isomeric benzofa]- and benzo[c]-... 

Besides 1-15 to 1-17, several other formylation methods are known.302 In one of these, dichloromethyl methyl ether formylates aromatic rings with Friedel-Crafts catalysts.303 ArCHClOMe is probably an intermediate. Orthoformates have also been used.304 In another method, aromatic rings are formylated with formyl fluoride HCOF and BF3.305 Unlike formyl chloride, formyl fluoride is stable enough for this purpose. This reaction was successful for benzene, alkylbenzenes, PhCl, PhBr, and naphthalene. Phenols can be regioselectively formylated in the ortho position in high yields by treatment with two equivalents of paraformaldehyde in aprotic solvents in the presence of SnCL and a tertiary amine.306 Phenols... 

Paraformaldehyde -in water rinse removers [PAINT - PAINT AND FINISH REMOVERS] (Vol 17) - [FIBERS - REGENERATED CELLULOSICS] (Vol 10) -phenolic resin preparation [PITENOLIC RESINS] (Vol 18)... 

A convenient method for the introduction of a formyl group, specifically in the ortho position of a phenol, involves reaction with tin(iv) chloride in the presence of tributylamine followed by treatment with paraformaldehyde.46 It is applicable to phenols with other electron-donating or -withdrawing substituents, and is illustrated by the conversion of p-cresol into 5-methyl-2-hydroxybenzaldehyde (Expt 6.112). The reaction is thought to proceed via two successive six-membered coordinated tin complexes. 

Resorcinol differs from other phenols in that it reacts readily with formaldehyde under neutral conditions at ambient temperature. To make stable adhesives, which can be cured at the point of use, they are prepared with less than a stoichiometric amount of formaldehyde. About two thirds of a mole of formaldehyde for each mole of resorcinol will give a stable resinous condensation product. The resin is formed into a liquid of convenient solids content and viscosity. Such solutions have infinite stability when stored in closed containers. Glue mixes formed at the point of use from these solutions, on addition of paraformaldehyde-containing hardeners, will have a useful life of several hours due to two principal factors (1) the paraformaldehyde depolymerizes to supply monomeric formaldehyde at a slow rate, as determined by the pH (2) the availability of the formaldehyde is also controlled by the kind and amount of alcohol in the solvent. Formaldehyde reacts with the alcohol to form a hemiacetal. This reaction is reversible and forms an equilibrium which exerts further control on the availability of the formaldehyde. 

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