C with formaldehyde

Condensation of urea (HjNCONHj) or melamine (C with formaldehyde (IlCH(d)... 

The condensation of /3-aminoacrolein with (61a,c) leads to the corresponding polymethylene-bridged tpys (66b,d) in low yields. The same systems may be prepared more effectively by the condensation of enamines (65a-c) with formaldehyde and subsequent azacyclization of the intermediate 1,5-diketone (Scheme 12).64 A Hantzsch approach to (66b) has also been reported.67 Benzaldehyde, 4-substituted benzaldehydes, and various other aryl aldehydes can be treated with (65a) to afford 4 -aryl derivatives of (66b) in moderate yields.69 A 48% yield of the monomethylene-bridged (66a) has been... 

When tri(hydroxymethyl)phosphine (347) reacts at 180-200°C with formaldehyde 5-methyl-l,3,5-dioxaphosphinane 5-oxide (348) is formed. The initial 5-hydroxymethyl compound undergoes a thermal Buckler-Trippett reaction under the reaction conditions (Scheme 71) <78ZOB97,78ZOB2653). 

The effect of the reactant ratio on the product distribution was investigated and experiments were carried out with formaldehyde-to-butyraldehyde molar ratios varying from 2 1 to 8 1. The results from two experiments performed at 60°C with formaldehyde-to-butyraldehyde molar ratios of 2 1 and 4 1 are shown in Figure 2. 

The reaction of arylaminomethyltetrahydroqmnoxalines 31a-c with formaldehyde leads to hexahydroimidazoquinoxalines 26a, b and the reaction with triethyl orthoformate in the presence of tetrafluoroboric acid gives imidazolium salts 32a-c (Scheme 4.14) (Benkovic et al. 1969, 1972). 

Calixarenes (from the Latin ca/ x) may be understood as artificial receptor analogues of the natural cyclodextrins (96,97). In its prototypical form they feature a macrocycHc metacyclophane framework bearing protonizable hydroxy groups made from condensation of -substituted phenols with formaldehyde (Fig. 15b). Dependent on the ring size, benzene derivatives are the substrates most commonly included into the calix cavity (98), but other interesting substrates such as C q have also been accommodated (Fig. 8c) (45). 

Most formaldehyde producers recommend a minimum storage temperature for both stabilized and unstabilized solutions. Figure 3 is a plot of data (17,18,122,126) for uiiinhibited (<2.0 wt% methanol) formaldehyde. The minimum temperature to prevent paraformaldehyde formation in unstabilized 37% formaldehyde solutions stored for one to about three months is as follows 35°C with less than 1% methanol 21°C with 7% methanol 7°C with 10% methanol and 6°C with 12% methanol (127). 

Acetylene is condensed with carbonyl compounds to give a wide variety of products, some of which are the substrates for the preparation of families of derivatives. The most commercially significant reaction is the condensation of acetylene with formaldehyde. The reaction does not proceed well with base catalysis which works well with other carbonyl compounds and it was discovered by Reppe (33) that acetylene under pressure (304 kPa (3 atm), or above) reacts smoothly with formaldehyde at 100°C in the presence of a copper acetyUde complex catalyst. The reaction can be controlled to give either propargyl alcohol or butynediol (see Acetylene-DERIVED chemicals). 2-Butyne-l,4-diol, its hydroxyethyl ethers, and propargyl alcohol are used as corrosion inhibitors. 2,3-Dibromo-2-butene-l,4-diol is used as a flame retardant in polyurethane and other polymer systems (see Bromine compounds Elame retardants). 

Isobutylene—Formaldehyde, Isobutylene is condensed with formaldehyde at 95°C to give the principal product 4,4-dimethyl-z -dioxane. In the second step, the dioxane is decomposed in the presence of an acid catalyst to isoprene, formaldehyde, and water. 

The aromatic rings of kraft lignins can be sulfonated to varying degrees with sodium sulfite at high temperatures (150—200°C) or sulfomethylated with formaldehyde and sulfite at low temperatures (<100° C). Oxidative sulfonation with oxygen and sulfite is also possible. 

Ghloromethylation. The reactive intermediate, 1-chloromethylnaphthalene [86-52-2] has been produced by the reaction of naphthalene in glacial acetic acid and phosphoric acid with formaldehyde and hydrochloric acid. Heating of these ingredients at 80—85°C at 101.3 kPa (1 atm) with stirring for ca 6 h is required. The potential ha2ard of such chloromethylation reactions, which results from the possible production of small amounts of the powerhil carcinogen methyl chloromethyl ether [107-30-2J, has been reported (21). 

The in situ process is simpler because it requires less material handling (35) however, this process has been used only for resole resins. When phenol is used, the reaction system is initially one-phase alkylated phenols and bisphenol A present special problems. As the reaction with formaldehyde progresses at 80—100°C, the resin becomes water-insoluble and phase separation takes place. Catalysts such as hexa produce an early phase separation, whereas NaOH-based resins retain water solubiUty to a higher molecular weight. If the reaction medium contains a protective coUoid at phase separation, a resin-in-water dispersion forms. Alternatively, the protective coUoid can be added later in the reaction sequence, in which case the reaction mass may temporarily be a water-in-resin dispersion. The protective coUoid serves to assist particle formation and stabUizes the final particles against coalescence. Some examples of protective coUoids are poly(vinyl alcohol), gum arabic, and hydroxyethjlceUulose. 

Batch syntheses comparable to those used for MDA produce 3,3 -dimethy1methy1enedi(cyclohexylamine) marketed under the trade name Laromia C-260. The starting aromatic diamiae, 3,3 -dimethy1methy1enediani1ine [838-88-0] is prepared from o-toluidine [95-53-4] condensation with formaldehyde. Similarly 3,3 -dimethyldicyclohexylaniiae [24066-10-2] may be produced (38) from o-toHdine [119-93-7] derived from o-nitrotoluene [88-72-2]. The resultant isomer mixtures are dependent on reduction conditions as ia MDA hydrogeaatioa. 

Condensation with Aldehydes and Ketones. Succinic anhydride and succinic esters in the presence of different catalysts react in the gas phase with formaldehyde to give citraconic acid or anhydride and itaconic acid (94—96). Dialkyl acyl succinates are obtained by reaction of dialkyl succinates with C 4 aldehydes over peroxide catalysts (97). 

Several kinds of products can be obtained by reaction of thioglycolic acid and its esters with aldehydes to form mercaptals, RCH(SCH2COOH)2, or with ketones to form thiolketals, RR C(SCH2COOH)2. Reaction with formaldehyde (qv) yields di- -butyhnethylene-bisthioglycolate [1433882-0] (MET ester) ... 

Chloromethylation (Blanc-QueletReaction). Benzene reacts with formaldehyde and hydrochloric acid ia the presence of ziac chloride to yield chloromethylbenzene [100-44-7], C HyCl (benzyl chloride) (29), a chemical iatermediate. 

Di- and Triisobutylcncs. Diisobutylene [18923-87-0] and tnisobutylenes are prepared by heating the sulfuric acid extract of isobutylene from a separation process to about 90°C. A 90% yield containing 80% dimers and 20% trimers results. Use centers on the dimer, CgH, a mixture of 2,4,4-trimethylpentene-1 and -2. Most of the dimer-trimer mixture is added to the gasoline pool as an octane improver. The balance is used for alkylation of phenols to yield octylphenol, which in turn is ethoxylated or condensed with formaldehyde. The water-soluble ethoxylated phenols are used as surface-active agents in textiles, paints, caulks, and sealants (see Alkylphenols). 

Tetrachloroethylene reacts with formaldehyde and concentrated sulfuric acid at 80°C to form 2,2-dichloropropanoic acid [75-99-0] (8). Copolymers with styrene, vinyl acetate, methyl acrylate, and acrylonitrile are formed in the presence of dibenzoyl peroxide (9,10). 

Pyrrole has been condensed under alkaline conditions with formaldehyde to give products of either N- or C-hydroxymethylation (Scheme 22). Although acid-catalyzed hydroxy-methylation is not a practical possibility, by addition of a reducing agent to the reaction mixture overall reductive alkylation can be achieved (Scheme 23). 

Ketones react with formaldehyde and perchloric acid to produce 2-isoxazolines and also with urea in a-methylnaphthalene at 200 °C (75MIP41600, 75ZOB2090, 79MI41612) with N-hydroxyurea they produce 3-hydroxy-2-carbamoylisoxazolidines or, after acid treatment, 2-isoxazolines are formed (Scheme 123) (75TL2337). 

Catalysts reduced with formaldehyde carry no adsorbed hydrogen and are less pyrophoric. Barium carbonate as a support may sometimes be advantageous in that the neutrality of the h3 drogenation mixture may be maintained. Barium sulfate or barium carbonate may be a better support than carbon, which may, in some instances, so strongly adsorb the derived product that recovery is difficult or incomplete. Palladium may be more completely and easily recovered from a spent catalyst where carbon rather than barium sulfate is the support. In general, the submitter prefers a catalyst prepared according to procedure C. 

Methanol is converted into formaldehyde by catalytic vapour phase oxidation over a metal oxide catalyst. In one variation of the process methanol is vaporised, mixed with air and then passed over the catalyst at 300-600°C. The formaldehyde produced is absorbed in water and then fed to a fractionating column. A 37% solution of formaldehyde in water is removed from the bottom of the column with some methanol as a stabiliser whilst excess methanol is taken from the top of the column and recycled. 

Aminos. There are two basic types of amino plastics - urea formaldehyde and melamine formaldehyde. They are hard, rigid materials with good abrasion resistance and their mechanical characteristics are sufficiently good for continuous use at moderate temperatures (up to 100°C). Urea formaldehyde is relatively inexpensive but moisture absorption can result in poor dimensional stability. It is generally used for bottle caps, electrical switches, plugs, utensil handles and trays. Melamine formaldehyde has lower water absorption and improved temperature and chemical resistance. It is typically used for tableware, laminated worktops and electrical fittings. 

Anhalamine. When mezcaline is condensed with formaldehyde it yields 6 7 8-trimethoxy-l 2 3 4-tetrahydrowoquinoline and the quaternary iodide obtained from this is identieal with dimethylanhalamine methiodide. It follows that 0-methylanhalamine must be 6 7 8-trimethoxy-1 2 3 4-tetrahydrot5oquinoline. The free hydroxyl group was shown to be at C by Spath and Beeke, who found that the produet (II R = Et), formed by 0-ethylation of anhalamine, gave 4 5-... 

Recently, the parent A -halomethylpyridinium halides 7a, 7b, and 7f-7i (X-CH2-Py X , X = Cl, Br) have been synthesized with yields up to 90% by treating a mixture of an equimolar amount of SOX2 (X = Cl, Br) and the corresponding pyridine with gaseous formaldehyde in CH2CI2 or MeCN at 0°C. Tire formaldehyde was generated externally from paraformaldehyde in a special apparatus (99JOC3113). 

Aliphatic and aromatic aldehydes condensed with 2-amino-(62BRP898414), 5-amino- (80AJC1147), or 8-amino-l,2,4-triazolo[l,5-cjpyrimidines (68JOC530) to give the related Schiff bases. Treatment of the 2-amino-5-methyl-l,2,4-triazolo[l,5-c]quinazoline 11 with formaldehyde and piperidine in the presence of acetic acid gave the 2-hydroxymethyl-amino-5-(2-piperidinoethyl) derivative 172. Utilization of aromatic aldehydes and piperidine in this reaction gave the 2-arylideneamino-5-styryl derivatives 173 (68CB2106) (Scheme 67). 

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