Diphenylmethane, preparation

By-products are formed in both preparations thus in the former, anthracene, and o- and p-dibenzylbenzenes are present in the fraction of high boiling point. Diphenylmethane is more conveniently obtained by the interaction of benzyl chloride and benzene in the presence of aluminium amalgam ... 

For uniformity with the stmctures given in the Colourindex the ammonium radical (9) is used for the amino-substituted xanthenes and the keto form for the hydroxy derivatives. The xanthene dyes may be classified into two main groups diphenylmethane derivatives, called pyronines, and triphenylmethane derivatives (eg, (4)), which are mainly phthaleins made from phthaUc anhydride condensations. A third much smaller group of rosamines (9-phenylxanthenes) is prepared from substituted ben2aldehydes. The phthaleins may be further subdivided into the following fluoresceins (hydroxy-substituted) rhodamines (amino-substituted), eg, (6) and mixed hydroxy/amino-substituted. 

In a variation of this method, isolation of the ben2hydrol derivative is not required. The methane base undergoes oxidative condensation in the presence of acid with the same or a different arylamine direcdy to the dye. New fuchsine [3248-91 -7] Cl Basic Violet 2 (16), is prepared by condensation of two moles of o-toluidine with formaldehyde in nitrobenzene in the presence of iron salts to give the corresponding substituted diphenylmethane base. This base is also not isolated, but undergoes an oxidative condensation with another mole of o-toluidine to produce the dye. 

Diphenylmethane Dyes. The diphenyhnethane dyes aie usually classed with the tiiaiyhnethane dyes. The dyes of this subclass are ketoimine derivatives, and only three such dyes are registered in the Colour Index. They ate Auramine O [2465-27-2J Cl Basic Yellow 2 (Cl 41000) (21, R = CHg), Auramine G [2151 -60-2] Cl Basic Yellow 3 (Cl 41005) (22), and Cl Basic Yellow 37 [6358-36-7] (Cl 41001) (21, R = C2H5). These dyes are still used extensively for the coloration of paper and in the preparation of pigment lakes. 

Diphenylmethane has been prepared with aluminum chloride as a catalyst from methylene chloride and benzene, from chloroform and benzene as a by-product in the preparation of triphenylmethane, and from benzyl chloride and benzene. It has been prepared by the reduction of benzophenone with hydriodic acid and phosphorus, or with sodium and alcohol. It has also been made by heating a solution of benzyl chloride in benzene with zinc dust, or with zinc chloride. The above method is only a slight modification of the original method of Hirst and Cohen. ... 

As described in U.S. Patent 2,421,714 (a) benzhydryl bromide is first prepared as follows 840 parts by weight of diphenylmethane is heated to 130°C with stirring. In the presence of a 200 watt electric light 6 inches from the flask, 880 parts of bromine is added slowly. Liberation of HBr occurs and addition requires 1 hour and 45 minutes. The temperature is maintained at 130°C for an additional 30 minutes. A fine stream of air is blown in to remove HBr and Brj while the reaction mixture cools. Benzene (180 parts) is added and the solution used immediately in (b) below. 

How would you prepare diphenylmethane, (Ph)2CH2, from benzene and an acid chloride ... 

The first example of siloxane-urea segmented copolymers were prepared by the direct reaction of aminopropyl-terminated polydimethyl siloxane oligomers and MDI (4,4 -diphenylmethane diisocyanate), in solution at room temperature as shown in the Reaction Scheme XI. 

Use of benzotriazole in the preparation of diphenylmethanes and triphenylmethanes has been reviewed." Benzotriazole is condensed with an aldehyde and then allowed to react with naphthols to form a diphenyl-methane benzotriazole derivative such as 69 (Scheme 9). The benzotriazole moiety in 69 is displaced by a Grignard reagent to give triphenylmethanes.79 100 This method allows for the preparation of triarylmethanes which contain three different aromatic rings. Compounds 70-72 are prepared by this method. 

This method has been applied successfully to the preparation of phenoxybenzene-4,4/-dithiol (84% of the theoretical amount), diphenylmethane-4,4 -dithiol, and m-sulfhydrylbenzoic acid4 (80%). It did not prove satisfactory for the preparation of higher-melting thiols of lower solubility, such as 2,7-naphtha-lenedithiol, 2,6-naphthalenedithiol, and 4,4 -biphenyldithiol. These were better prepared by the use of tin (II) chloride 2-hy-drate in glacial acetic acid saturated with hydrogen chloride.6... 

Polyurethane networks were prepared from polyoxypropylene (POP) triols(Union Carbide Niax Polyols) after removal of water by azeotropic distillation with benzene. For Niax LHT 240, the number-average molecular weight determined by VPO was 710 and the number-average functionality fn, calculated from Mjj and the content of OH groupSj determined by using excess phenyl isocyanate and titration of unreacted phenyl isocyanate with dibutylamine, was 2.78 the content of residual water was 0.02 wt.-%. For the Niax LG-56, 1 =2630, fn=2.78, and the content of H2O was 0.02wt.-%. The triols were reacted with recrystallized 4,4"-diphenylmethane diisocyanate in the presence of 0.002 wt.-% dibutyltin dilaurate under exclusion of moisture at 80 C for 7 days. The molar ratio r0H = [OH]/ [NCO] varied between 1.0 and 1.8. For dry samples, the stress-strain dependences were measured at 60 C in nitrogen atmosphere. The relaxation was sufficiently fast and no extrapolation to infinite time was necessary. 

A suspension of sodium amide (0.275 mole) (Note 1) in liquid ammonia is prepared in the following manner in a 1-1. threenecked flask equipped with an air condenser (Note 2), a sealed mechanical stirrer, and a dropping funnel. Commercial anhydrous liquid ammonia (600 ml.) is introduced by pouring from an Erlenmeyer flask (Note 3). To the stirred liquid ammonia is added a small piece of sodium. After the appearance of a permanent blue color (Note 4) a few crystals of ferric nitrate hydrate (ica. 0.1 g.) are added, followed by small pieces of freshly cut sodium (Note 5) until 6.32 g. (0.275 g. atom) has been added. After all the sodium is converted to the amide (Note 6), 42.0 g. (0.250 mole) of diphenylmethane (Note 7) in 20 ml. of anhydrous ether is added (Note 8). The deep red suspension is stirred for 15 minutes. n-Butyl bromide (37.6 g., 0.274 mole) (Note 7) in... 

Some of the above-mentioned catalysts or precursors are commercially available, such as the Corey catalyst (,S) - 3,3 - d i p h e n yI -1 - met h y 1 tctralr yd ro- 3 H - py r-rolo[l,2-c] [l,3,2]oxazaborole (Me-CBS). The amino alcohol (5)-(—)-2-amino-3-methyl-l,l -diphenylmethan-l-ol, used as the ligand in the Itsuno catalyst is also readily available. The ligand used to prepare the oxazaphospholidine or oxazaphosphinamide complex (from Wills) can be synthesized easily from commeri-cally available material. The preparation of the Bolm (3-hydroxysulfoximine catalyst will be described in this chapter (Figure 11.2). 

Tryptamine from Tryptophan. Prepare a suspension of 1 g tryptophan (preferably L-tryptophan) in 40 g of warm diphenylmethane. In a stream of nitrogen (nitrogen atmosphere) gently reflux the suspension until the CO2 stops evolving (10 to 30 min). Cool, evaporate in a vacuum, treat the resulting residue with about 80 ml of benzene, saturate with dry HCl and filter off the precipitate. Wash the precipitate with hexane and dry to get the tryptamine in about 60% yield. 

We have prepared and characterized three linear isosorbide containing polyurethanes with toluene diisocyanate (TDI), 4,4 -diphenylmethane diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HMDI) P(I-TDI), P(I-MDI), and P(I-HMDI). These polyurethanes have been synthesized as described in the experimental section by solution polymerization of isosorbide with the corresponding diisocyanate in dimethylacetamide using dibutyl-tin dilaurate as the catalyst at 75 C for 24 hours. All polymers have been isolated in quantitative yield by precipitation in methanol or water (5). 

A key factor in the preparation of polyurethanes is the reactivity of the isocyanates. Aromatic diisocyanates are more reactive than aliphatic diisocyanates, and primary isocyanates react faster than secondary or tertiary isocyanates. The most important and commercially most readily accessible diisocyanates are aliphatic and colorless hexamethylene-1,6-diisocyanate (HDI), isophorone diisocyanate (IPDI),and aromatic, brownish colored diphenylmethane-4,4 -diiso-cyanate (MDI), 1,5-naphthalenediisocyanate, and a 4 1 mixture of 2,4- and 2,6-toluenediisocyanates (TDI). 

Solvents and potassium ferf-butoxide were purified or prepared as described (18). Rubidium-, sodium-, and lithium ferf-butoxides were prepared by the method described for potassium ferf-butoxide (20). Diphenylmethane (Eastman Kodak Co.) was vacuum-distilled. Fluorene... 

Preparation of Azobis(diphenylmethane) by Hydrogen Peroxide Oxidation... 

Poly(2-vinylpyridinc)- >-poly(w-bcxylisocyanatc), (I), was prepared by the authors (2) by living polymerization using potassium diphenylmethane as initiator and then adding sodium tetraphenylborate to replace the counter cation with a sodium ion. The product was used in optical applications such as an optical switch device. 

To address this concern uretonimine-modified isocyanates with improved low-temperature properties were prepared using 4,4 -diphenylmethane diisocyanate catalyzed with 3-methyl-l-phenyl-3-phospholene-l-oxide. The formation of uretonimine was consistently higher than uretdione formation using this catalyst. The uretonimine-modified isocyanate can be stored at temperatures substantially lower than ambient temperature while still remaining liquid. In addition it is soluble in melted 4,4 -diphenylmethane diisocyanate. 

TABLE 1. Scoping Reactions for Preparation of Urctonimine-Modified Isocyanate Using 93.80% 4,4 -Diphenylmethane Diisocyanate Containing 6.20% 2,4 -Diphenylmethane Diisocyanate Conducted at 105-108°C Using 3-Methyl-l-phenyl-3-phosphoIene-l-oxide as Catalyst... 

Other semi-2-IPNs [52] processed by the freeze-drying method included IPN from 4,4 -bismaleimido diphenylmethane (BMI) and linear BTDA/3,4 -ODA polyamic acid that were dissolved in 1,3,5-trioxane (Fig. 16). The resulting semi-2-IPNs exhibited higher Tgs and reduced phase separation, and contained no plasticizing solvent. A comparison of unidirectional properties of composites prepared by the freeze-dry process to those by traditional solvent evaporation process is presented in Table 13. The freeze-drying method for the preparation of IPNs appears to be superior to previous technology. 

Diphenylmethyllithium [881-42-5] can be prepared by the metalation reaction of butyllithium with diphenylmethane in addition, the adduct of butyllithium and 1,1-diphenylethylene is conveniendy prepared in either hydrocarbon or polar solvents such as THF as shown in equation 18. 

In the course of the previous work we have prepared compounds for comparative purposes, one of which has been reported by Gierer. He and his co-workers 15) synthesized an unsymmetrical diphenylmethane by acid-catalyzed condensation of syringyl alcohol and 2-methoxy-4-methyl-phenol and assumed substitution in the 6-position of the guaiacol nucleus. We repeated this synthesis and prepared an isomeric material by base-catalyzed condensation of the same starting materials. Our interpretation of the modes of synthesis and the NMR spectra of the two compounds is that Gierer s compound most probably is 3, 4-dihydroxy-6 -methyl-3,4, 5-trimethoxydiphenylmethane and that the compound prepared under basic conditions is 2, 4-dihydroxy-5 -methyl-3,3, 5-trimethoxydiphenylmethane, the structure claimed by Gierer. We do not, however, have unequivocal structural evidence and our data are summarized under Experimental. 

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