Phenol polymerization with formaldehyde

Uses ndReactions. The Prins reaction of 3-carene with formaldehyde in acetic acid gives mainly 2-carene-4-methanol acetate, which when saponified produces the 2-carene-4-methanol, both of which are commercial products of modest usage (60). 3-Carene (28) also reacts with acetic anhydride with a catalyst (ZnCl2) to give 4-acetyl-2-carene (29) (61), which is also a commercial product. Although 3-carene does not polymerize to produce terpene resins, copolymerization with phenol has been successfully commercialized by DRT in France (62). 

Uses of Formaldehyde. Formaldehyde is the simplest and most reactive aldehyde. Condensation polymerization of formaldehyde with phenol, urea, or melamine produces phenol-formaldehyde, urea formaldehyde, and melamine formaldehyde resins, respectively. These are important glues used in producing particle hoard and plywood. 

Acid catalysts, such as metal oxides and sulfonic acids, generally catalyze condensation polymerizations. However, some condensation polymers form under alkaline conditions. For example, the reaction of formaldehyde with phenol under alkaline conditions produces methy-lolphenols, which further condense to a thermosetting polymer. 

A plant had a runaway reaction with a phenol-formaldehyde polymerization reaction. The result was one fatality and seven injuries and environmental damage. The runaway reaction was triggered when, contrary to standard operating procedures, all the raw materials and... 

Thermosets are formed by crosslinking (curing) of reactive linear and branched macromolecules and can be manufactured by polycondensation, polymerization and polyaddition. Thermosets can therefore be processed once only with the application of heat and pressure to form semi-finished products or finished articles and cannot be recovered their processing is irreversible. Amongst the most familiar thermosets are the combinations of formaldehyde with phenol, resorcinol etc. (phenolics), urea, aniline, melamine and similar combinations (aminoplastics). 

The polymerization products of propylene have been observed to be saturated hydrocarbon polymers and terpenelike unsaturated hydrocarbons (Kuhn, 64). The condensation of formaldehyde with phenols and cyclohexanols by means of aqueous hydrogen fluoride has also been observed (Badertscher el al., 65). 

Phenolic polymers are obtained by the polymerization of phenol (/ = 3) with formaldehyde (/ = 2) [Bogan, 1991 Brydson, 1999 Kopf, 1988 Lenz, 1967 Manfredi et al., 2001 Peng... 

Drumm, M. F. and J. R. LeBlanc, The Reactions of Formaldehyde with Phenols, Melamine, Aniline and Urea, Chap. 5 in Step-Growth Polymerizations, D. H. Solomon, ed., Marcel Dekker, New York, 1972. 

The carbonyl group of formaldehyde is highly susceptible to nucleophilic attack and this monomer can be polymerized with almost any base. Metal alkyls, alkoxides, phenolates, and carboxylates, hydrated alumina, amines, phosphines, and pyridine are effective in polymerizing formaldehyde. 

The diarylation reaction is especially common with phenols (the diaryl product here is called a bisphenol). The reaction is normally carried out in alkaline solution on the phenolate ion.327 The hydroxymethylation of phenols with formaldehyde is called the Lederer-Manasse reaction. This reaction must be carefully controlled,328 since it is possible for the para and both ortho positions to be substituted and for each of these to be rearylated, so that a polymeric structure is produced ... 

Dase-catalyzed phenol-formaldehyde resins polymerized with a mole ratio of formaldehyde to phenol greater than one pose an interesting molecular weight characterization problem. This system is a dynamic one with active methylol end groups. Branched and crosslinked structures are formed, and in general, the separation of the resin from the reaction mixture is difficult. Figure 1 illustrates the chemical nature of a resole resin. 

REPPE PROCESS. Any of several processes involving reaction of acetylene (1) with formaldehyde to produce 2-butync-l,4-diol which can be converted to butadiene (2) with formaldehyde under different conditions to produce propargyl alcohol and, form this, allyl alcohol (3) with hydrogen cyanide to yield acrylonitrile (4) with alcohols to give vinyl ethers (5) with amines or phenols to give vinyl derivatives (6) with carbon monoxide and alcohols to give esters of acrylic acid (7) by polymerization to produce cyclooctatetraene and (8) with phenols to make resins. The use of catalysis, pressures up to 30 atm, and special techniques to avoid or contain explosions are important factors in these processes. 

Under acidic conditions, furfuryl alcohol polymerizes to black polymers, which eventually become crosslinked and insoluble in the reaction medium. The reaction can be very violent and extreme care must be taken when furfuryl alcohol is mixed with any strong Lewis acid or Brn nstad acid. Copolymer resins are formed with phenolic compounds, formaldehyde and/or other aldehydes. In dilute aqueous acid, the predominant reaction is a ring opening hydrolysis to form levulinic acid [123-76-2] (52). In acidic alcoholic media, levulinic esters are formed. The mechanism for this unusual reaction in which the hydroxymethyl group of furfuryl alcohol is converted to the terminal methyl group of levulinic acid has recendy been elucidated (53). 

L.B. Manfredi, C.C. Riccardi, O. de la Osa, and A. Vazquez. Modelling of resol resin polymerization with various formaldehyde/phenol molar ratios. Polymer International, 50 796-802, 2001. 

Besides, furfural polymerizes in the presence of an acid catalyst with phenol, urea, and acetone. In this regard, the phenol-furfural and urea-furfural resins are important [221-223], Furfural reacts usually as does all a-substituted aldehydes in this regard, with phenol it condenses in the presence of either alkali or acid to form synthetic resins in a reaction that is very similar to that of phenol with formaldehyde or acetaldehyde [223],... 

It also can be produced directly from natural gas, methane, and other aliphatic hydrocarbons, but this process yields mixtures of various oxygenated materials. Because both gaseous and liquid formaldehyde readily polymerize at room temperature, formaldehyde is not available in pure form. It is sold instead as a 37 percent solution in water, or in the polymeric form as paraformaldehyde [HO(CH20)nH], where n is between 8 and 50, or as trioxane (CH20)3. The greatest end use for formaldehyde is in the field of synthetic resins, either as a homopolymer or as a copolymer with phenol, urea, or melamine. It also is reacted with acetaldehyde to produce pentaerythritol [C(CH2OH)4], which finds use in polyester resins. Two smaller-volume uses are in urea-formaldehyde fertilizers and in hexamethylenetetramine, the latter being formed by condensation with ammonia. 

If polymeric procyanidins extractable from conifer tree barks are to be used in adhesive formulations requiring condensation with phenol-formaldehyde prepolymers, these reactions must be performed at acidic pH conditions, and because of solubility limitations, this will probably require the use of sulfonate derivatives. 

Usually, phenolphthalein-derived polymers are polymerized through the hydroxyl groups, thus destroying their well-known indicator properties. There is one example in which phenolphthalein and o-cresolphthalein 284 have been polymerized with formaldehyde to form phenol/formaldehyde type polymers, for example, 285. These polymers retain the indicating properties of the monomers with potential application in pFl test strips and optical pH sensors <2005PSA1019>. 

Indeed. Mannich aminomcthylation represents the repetitive-cumulative reaction giving rise to several types of formaldehyde resins the most relevant of these are melamine resins, which have been abundantly investigated and reported in a quite large series of patents. Melamines, as well as guanamincs, have also been tested in combination with phenols or urea derivatives, behaving as Mannich substrates in this type of reaction. Further examples of Mannich polymerization involving other amines and acetonic, phenolic, etc., substrates arc found in Chap. Ill, A (sec also 425, Chap. I1I.C.I). 

The first type concerns aminomcthylation giving rise to the mactomolecular network starting from polyfunctional polymeric substrates and/or amines. Hardening of phenolic novolacs-- and other resins with urotropinc belongs to this type of reaction. The process may be carried out in the presence of protcic molecules, which are thus inserted into the cured material. - Similarly, the crosslinking of collagen or other proteic macromolccules with formaldehyde, or with mixtures of aldehydes, is frequently encountered (see also Chap. HI, C.2).- - ... 

The first completely synthetic ion exchange resins were prepared by B. A. Adams and E. L. Holmes in 1935. The basis of their synthesis was the condensation polymerization of methanal (formaldehyde) with phenol or polysubstituted benzene compounds to give, after... 

The pyrazolone can be incorporated directly in the polymer by utilizing a polymer-forming derivative such as a 1 -(amino or hydroxy -phenyl)pyrazolone in a phenol (or aniline)-formaldehyde polymerization. Alternatively, the pyrazolone nucleus can be combined with a synthetic or natural polymer by reaction of a functional group in the pyrazolone with the polymer. Thus, a 1-formylphenyl type is used to form a polyvinyl acetal. A compilation of such reactions is given in Part 1, Chapter II, Section 14, pp. 108-110. 

The phenol-formaldehyde prepolymers were polymerized with 4-(l-phenylethyl)phenol (para-styrenated phenol) (equation 39). The sulfonation of the resulting polymer gave a cation exchange resin, which is useful as an acid catalyst . ... 

Matsumoto and coworkers incorporated poly(A -(hydroxyphenyl)maleimides) into composite materials with phenol-formaldehyde resins. Poly(iV-(4-hydroxyphenyl)malei-mide) has been shown to form miscible blends with phenolic resins and, after crosslinking, produces composites with good thermal and chemical stability. The hardening or crosslinking agent most commonly used is hexamethylenetetramine (HMTA), to form an insolnble and infusible three-dimensional polymeric network (Scheme 29). 

It was reported that the reaction of starch with phenol in the presence of a Lewis acid such as AICI3 resulted in resins of controlled melt viscosity.252 Probably, the product results from the hydrolysis of starch to glucose with conbversion of the latter into 5-(hydroxymethyl)-2-furaldehyde, which subsequently condensed with phenol.253 The reaction of starch with phenol without any catalyst required temperatures between 200 and 260 °C, and the resultant resinous product was then hardened by condensation with formaldehyde.254 Mastication of either glycerol or phenol with starch and water was said not to involve alcoholysis, but instead results in the formation of polymeric products.255 Reactions with gossypol256,257 and propylene glycol258 that were performed in the presence of a basic catalyst were in fact polymerization reactions and not alcoholyses. 

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