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| Names | |
|---|---|
| Preferred IUPAC name 1,1′-Methylenedibenzene[1] | |
Other names
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| Identifiers | |
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3D model (JSmol) | |
| Abbreviations |
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| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.002.708 |
| MeSH | Diphenylmethane |
| UNII | |
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| Properties | |
| (C6H5)2CH2 | |
| Molar mass | 168.239 g·mol−1 |
| Appearance | colourless oil |
| Density | 1.006 g/mL |
| Melting point | 22 to 24 °C (72 to 75 °F; 295 to 297 K) |
| Boiling point | 264 °C (507 °F; 537 K) |
| 14 mg/L | |
| Acidity (pKa) | 32.2 |
| −115.7×10−6 cm3/mol | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | flammable |
| Flash point | > 110 °C; 230 °F; 383 K |
| Related compounds | |
Related compounds | Diphenylmethanol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Diphenylmethane is anorganic compound with theformula(C6H5)2CH2 (often abbreviatedCH2Ph2). The compound consists ofmethane wherein two hydrogen atoms are replaced by twophenyl groups. It is a white solid.
Diphenylmethane is a commonskeleton in organic chemistry. The diphenylmethyl group is also known asbenzhydryl.
It is prepared by theFriedel–Crafts alkylation ofbenzyl chloride withbenzene in the presence of aLewis acid such asaluminium chloride:[2]
The methylene group in diphenylmethane is mildly acidic with apKa of 32.2, and so can be deprotonated withsodium amide.[3]
The resultingcarbanion can be alkylated. For example, treatment withn-bromobutane produces 1,1-diphenylpentane in 92% yield.[4]
Alkylation of variousbenzhydryl compounds has been demonstrated using the corresponding alkyl halides, both primary (benzyl chloride, β-phenylethyl chloride, and n-octyl bromide) and secondary (benzhydryl chloride, α-phenylethyl chloride, andisopropyl chloride), in yields between 86 and 99%.[3][4]
The acidity of the methylene group in diphenylmethane is due to the weakness of the(C6H5)2CH−H, which has abond dissociation energy (BDE) of 340 kJ/mol (82 kcal/mol).[5] This is well below the published bond dissociation energies for comparableC−H bonds inpropane, where the BDE of(CH3)2CH−H is 413 kJ/mol (98.6 kcal/mol), andtoluene, where the BDE of(C6H4)CH2−H is 375 kJ/mol (89.7 kcal/mol).[6][7]
