Formaldehyde furan

Injecting epoxy, furan, or furan-formaldehyde resins into poorly consolidated formations to consolidate them was a common sand control practice for thin highly productive formations (44-46). Organic solvents (46) and silane coupling agents (47) are used to promote adhesion of the resin to the rock surface. Excess resin is flushed deeper into the formation to minimize resin hardening in the flow channels since this would reduce formation permeability. 

FF Furan-formaldehyde resins rubber nitrile rubber ... 

FF furan-formaldehyde FRTS fiber-reinforced thermoset... 

Tetrafluoroethylene-hexafluoropropylene rubber see PFEP Furan-formaldehyde resins Vinylidene fluoride-hexafluoropropylene rubber Fluorinated silicone rubber... 

FF Abbreviation for Furan-Formaldehyde Polymer. See Furan Resin. 

Alkynyl)oxiranes also react with carbon nucleophiles to afford furan derivatives. Furanes of different types are obtained depending on the structure of the substrates. 7-Methyl-2-ethynyloxirane (95) reacts with acetoacetate to give the furan 97 by the elimination of formaldehyde from the cyclized product 96. The hydroxy ester of the alkylidenefuran 98 and the corresponding lactone 99 are obtained by the reaction of i-methyl-2-(2-propynyI)oxirane[40, 42]. 

Thiophene and selenophene can be chloromethylated by treatment with formaldehyde and hydrochloric acid. Depending on the conditions, 2-chloromethyl or 2,5-bis(chloromethyl) derivatives are obtained. The chloromethylation of benzo[6]thiophene gives the 3-chloromethyl derivative and that of benzo[6]furan the 2-chloromethyl compound (71AHC(13)235). 

An important extension of these reactions is the Mannich reaction, in which aminomethyl-ation is achieved by the combination of formaldehyde, a secondary amine and acetic acid (Scheme 24). The intermediate immonium ion generated from formaldehyde, dimethyl-amine and acetic acid is not sufficiently reactive to aminomethylate furan, but it will form substitution products with alkylfurans. The Mannich reaction appears to be still more limited in its application to thiophene chemistry, although 2-aminomethylthiophene has been prepared by reaction of thiophene with formaldehyde and ammonium chloride. The use of A,iV-dimethyf (methylene) ammonium chloride (Me2N=CH2 CF) has been recommended for the iV,iV-dimethylaminomethylation of thiophenes (83S73). 

The most recent entrant-to the. club of commodity chemicals is 1,4-butanediol (BDO), a petrochemical used in some of the more specialized applications such as chemical intermediates for the production of tetrahydro-furane and gama-butyrolactone, polybutylene terephthalate, and the more familiar polyurethanes. Traditionally, the Reppe process was the primary route to BDO, based bn acetylene and formaldehyde feeds. More recently, the share of BDO from butane and propylene oxide based production has grown rapidly. 

Uses. Solvent for cellulose ethers, esters, resins, and dyes liquid propellant binder in foundry cores manufacture of resins including furfuryl alcohol resin (furan resin) and furfuryl alcohol-formaldehyde resins... 

Oxyiminium cations formed from iV,0-diaIkyhydroxylamines and formaldehyde are sufficiently reactive for Mannich reactions with activated arenes. Mannich reactions of oxyiminium cations with indoles (e.g. 74, equation 48) " as well as pyrroles and furans but not phenol and thiophene have been reported. 

The major products formed from hexoses that react in aqueous acidic solution are 5-(hydroxymethyl)-2-furaldehyde, levulinic acid, and polymeric materials. In addition, many minor dehydration products are found. In a study41 of D-fructose, 2-(2-hydroxyacetyl)furan (13), 2-acetyl-3-hydroxyfuran (isomaltol 16), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, and 3,4,5-trihydroxy-3,5-hexadien-2-one (acetylformoin) were identified. Products not formed solely by dehydration mechanisms include acetone,56 formaldehyde, acetalde-... 

Other sources of "background" cancer are trace levels of chemicals found in drinking water, food, building materials, and common activities. Such exposures are not natural, but they are ubiquitous because they are associated with elements of modern life that most people deem essential. For example, some of the chlorine used to chlorinate public drinking water forms chloroform. Vapors from dry-cleaned clothes (tetra- and trichloroethylene) mix with the air in closets. Building materials contain formaldehyde. Dioxins, furans, and PCBs are found in the food chain. 

Fluoioboric acid, 57, III 2 Fluoro-2-methylbutane, 57, 7 3 1-Fluoiooctane, 57, 73 1-Fluoio-2-phenylethane, 57, 73 Formaldehyde 57,95,103 Formalin, 55, 45 Formamide 57, 103 Formamide, AVV-dimethyl-, 55, 58 Formic acid, 57, 95, 103 Free radical cyclization, 55, 57 Fukmone, 58, 162, 163 Fumaric acid, 58, 167 Fumaric acid, methyl ester, 56, 63 Furan, 58, 18, 22, 24... 

The ion (97), acting as an electrophilic reagent, can also attack another molecule of the heterocyclic compound. Thiophene with benzaldehyde or chloral gives the dinuclear product (100 R = Ph, CC13). Pyrrole and furan react with acetone to form tetranuclear derivatives of type (101 Z = NH, O). Pyrroles with a single free position react analogously to thiophene e.g. two molecules of 3-ethoxycarbonyl-2,4-dimethylpyrrole with formaldehyde afford the dipyrromethane (102). 

Mono- and di-alkylated furans were synthesized in a one-pot preparation from 2-propynyl-2-tetrahydropyranyl ether (106), butyllithium and formaldehyde. The intermediate allenyl ether (107) presumably cyclizes via a 2-(2-tetrapyranyloxy)-2,5-dihydrofuran (108) to afford the heterocycle (109) (79AG(E)875). In a similar manner, singly and doubly branched tetrahydropyranyloxybutynolates afforded the substituted furans (110) (Scheme 20). The thermocatalytic isomerization of ethyl l-methyl-2-phenylcyclopropene-3-carboxylate yielded the furan, possibly by a 1,3-sigmatropic displacement step or by a non-concerted biradical intermediate (75T2495). 

Hydrogenated furans can be prepared from the reaction of 7-olefins with formaldehyde in trifluoroacetic acid kinetics suggest that die reactions proceed via equilibrium addition of the protonated aldehyde.184... 

Kinetics data suggest that the mechanism for the formation of hydrogenated furan from a-alkenes and formaldehyde involves the reversible addition of protonated formaldehyde to the alkene 45... 

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