Diphenylmethane

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Diphenylmethane
Diphenylmethane.svg
Diphenylmethane-from-xtal-3D-bs-17.png
Names
Preferred IUPAC name
1,1′-Methylenedibenzene [1]
Other names
Diphenylmethane
Benzylbenzene
Identifiers
3D model (JSmol)
AbbreviationsBnPh, Ph2CH2
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.002.708 OOjs UI icon edit-ltr-progressive.svg
MeSH Diphenylmethane
PubChem CID
UNII
  • InChI=1S/C13H12/c1-3-7-12(8-4-1)11-13-9-5-2-6-10-13/h1-10H,11H2 Yes check.svgY
    Key: CZZYITDELCSZES-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C13H12/c1-3-7-12(8-4-1)11-13-9-5-2-6-10-13/h1-10H,11H2
    Key: CZZYITDELCSZES-UHFFFAOYAV
  • c1c(cccc1)Cc2ccccc2
Properties
C13H12
Molar mass 168.234
Appearancecolourless 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)33
-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 their standard state (at 25 °C [77 °F], 100 kPa).
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Diphenylmethane is an organic compound with the formula (C6H5)2CH2 (often abbreviated CH
2
Ph
2
). The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups. It is a white solid.

Contents

Diphenylmethane is a common skeleton in organic chemistry. The diphenylmethyl group is also known as benzhydryl .

Synthesis

It is prepared by the Friedel–Crafts alkylation of benzyl chloride with benzene in the presence of a Lewis acid such as aluminium chloride: [2]

C6H5CH2Cl + C6H6 → (C6H5)2CH2 + HCl

Reactivity of the C-H bond

The methylene group in diphenylmethane is mildly acidic with a pKa of 32.2, and so can be deprotonated with sodium amide. [3]

(C6H5)2CH2 + NaNH2 → (C6H5)2CHNa + NH3

The resulting carbanion can be alkylated. For example, treatment with n-bromobutane produces 1,1-diphenylpentane in 92% yield. [4]

(C6H5)2CH + CH3CH2CH2CH2Br → (C6H5)2CHCH2CH2CH2CH3 + Br

Alkylation of various benzhydryl 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, and isopropyl 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)2CHH bond, which has a bond dissociation energy of 82 kcal mol1 (340 kJ mol1). [5] This is well below the published bond dissociation energies for comparable CH bonds in propane, where BDE((CH3)2CHH)=98.6 kcal mol1, and toluene, where BDE(C6H5CH2H)=89.7 kcal mol1. [6] [7]

See also

Related Research Articles

<span class="mw-page-title-main">Amide</span> Organic compounds of the form RC(=O)NR′R″

In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula R−C(=O)−NR′R″, where R, R', and R″ represent any group, typically organyl groups or hydrogen atoms. The amide group is called a peptide bond when it is part of the main chain of a protein, and an isopeptide bond when it occurs in a side chain, as in asparagine and glutamine. It can be viewed as a derivative of a carboxylic acid with the hydroxyl group replaced by an amine group ; or, equivalently, an acyl (alkanoyl) group joined to an amine group.

<span class="mw-page-title-main">Piperidine</span> Chemical compound

Piperidine is an organic compound with the molecular formula (CH2)5NH. This heterocyclic amine consists of a six-membered ring containing five methylene bridges (–CH2–) and one amine bridge (–NH–). It is a colorless liquid with an odor described as objectionable, typical of amines. The name comes from the genus name Piper, which is the Latin word for pepper. Although piperidine is a common organic compound, it is best known as a representative structure element within many pharmaceuticals and alkaloids, such as natural-occurring solenopsins.

In organic chemistry, a carbanion is an anion in which carbon is negatively charged.

<span class="mw-page-title-main">Imine</span> Organic compound or functional group containing a C=N bond

In organic chemistry, an imine is a functional group or organic compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions.

<span class="mw-page-title-main">Triphenylmethane</span> Chemical compound

Triphenylmethane or triphenyl methane (sometimes also known as Tritan), is the hydrocarbon with the formula (C6H5)3CH. This colorless solid is soluble in nonpolar organic solvents and not in water. Triphenylmethane is the basic skeleton of many synthetic dyes called triarylmethane dyes, many of them are pH indicators, and some display fluorescence. A trityl group in organic chemistry is a triphenylmethyl group Ph3C, e.g. triphenylmethyl chloride (trityl chloride) and the triphenylmethyl radical (trityl radical).

<span class="mw-page-title-main">Benzyl group</span> Chemical group (–CH₂–C₆H₅)

In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure R−CH2−C6H5. Benzyl features a benzene ring attached to a methylene group group.

<span class="mw-page-title-main">Benzoyl chloride</span> Organochlorine compound (C7H5ClO)

Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C7H5ClO. It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring with an acyl chloride substituent. It is mainly useful for the production of peroxides but is generally useful in other areas such as in the preparation of dyes, perfumes, pharmaceuticals, and resins.

<span class="mw-page-title-main">Biphenyl</span> Chemical compound

Biphenyl is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one hydrogen may use the prefixes xenyl or diphenylyl.

<span class="mw-page-title-main">Diazonium compound</span> Group of organonitrogen compounds

Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. The parent compound where R is hydrogen, is diazenylium.

<span class="mw-page-title-main">Iminium</span> Polyatomic ion of the form >C=N< and charge +1

In organic chemistry, an iminium cation is a polyatomic ion with the general structure [R1R2C=NR3R4]+. They are common in synthetic chemistry and biology.

Benzyl bromide is an organic compound with the formula C6H5CH2Br. The molecule consists of a benzene ring substituted with a bromomethyl group. It is a colorless liquid with lachrymatory properties. The compound is a reagent for introducing benzyl groups.

Benzeneselenol, also known as selenophenol, is the organoselenium compound with the chemical formula C6H5SeH, often abbreviated PhSeH. It is the selenium analog of phenol. This colourless, malodorous compound is a reagent in organic synthesis.

<span class="mw-page-title-main">Benzyl cyanide</span> Chemical compound

Benzyl cyanide (abbreviated BnCN) is an organic compound with the chemical formula C6H5CH2CN. This colorless oily aromatic liquid is an important precursor to numerous compounds in organic chemistry. It is also an important pheromone in certain species.

Organoiodine chemistry is the study of the synthesis and properties of organoiodine compounds, or organoiodides, organic compounds that contain one or more carbon–iodine bonds. They occur widely in organic chemistry, but are relatively rare in nature. The thyroxine hormones are organoiodine compounds that are required for health and the reason for government-mandated iodization of salt.

In organic chemistry, dehalogenation is a set of chemical reactions that involve the cleavage of carbon-halogen bonds; as such, it is the inverse reaction of halogenation. Dehalogenations come in many varieties, including defluorination, dechlorination, debromination, and deiodination. Incentives to investigate dehalogenations include both constructive and destructive goals. Complicated organic compounds such as pharmaceutical drugs are occasionally generated by dehalogenation. Many organohalides are hazardous, so their dehalogenation is one route for their detoxification.

<span class="mw-page-title-main">Diphenyldichloromethane</span> Chemical compound

Diphenyldichloromethane is an organic compound with the formula (C6H5)2CCl2. It is a colorless solid that is used as a precursor to other organic compounds.

<span class="mw-page-title-main">9,10-Dihydroanthracene</span> Chemical compound

9,10-Dihydroanthracene is an organic compound that is derived from the polycyclic aromatic hydrocarbon anthracene. Several isomers of dihydroanthracene are known, but the 9,10 derivative is most common. It is a colourless solid that is used as a carrier of H2 as a hydrogen-donor.

In organophosphorus chemistry, an aminophosphine is a compound with the formula R3−nP(NR2)n where R = H or an organic substituent, and n = 0, 1, 2. At one extreme, the parents H2PNH2 and P(NH2)3 are lightly studied and fragile, but at the other extreme tris(dimethylamino)phosphine (P(NMe2)3) is commonly available. Intermediate members are known, such as Ph2PN(H)Ph. These compounds are typically colorless and reactive toward oxygen. They have pyramidal geometry at phosphorus.

<span class="mw-page-title-main">Tris(trimethylsilyl)silane</span> Chemical compound

Tris(trimethylsilyl)silane is the organosilicon compound with the formula (Me3Si)3SiH (where Me = CH3). It is a colorless liquid that is classified as a hydrosilane since it contains an Si-H bond. The compound is notable as having a weak Si-H bond, with a bond dissociation energy estimated at 84 kcal/mol. For comparison, the Si-H bond in trimethylsilane is 94 kcal/mol. With such a weak bond, the compound is used as a reagent to deliver hydrogen atoms. The compound has been described as an environmentally benign analogue of tributyltin hydride.

In organic chemistry, methylenation is a chemical reaction that inserts a methylene group into a chemical compound:

References

  1. International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 452. doi:10.1039/9781849733069. ISBN   978-0-85404-182-4.
  2. W. W. Hartman and Ross Phillips (1934). "Diphenylmethane". Organic Syntheses. 14: 34. doi:10.15227/orgsyn.014.0034.
  3. 1 2 Hauser, Charles R.; Hamrick, Phillip J. (1957). "Alkylation of Diphenylmethane with Alkyl Halides by Sodium Amide. Substitution versus β-Elimination. Relative Acidities of Diphenylmethane and Ammonia". J. Am. Chem. Soc. 79 (12): 3142–3145. doi:10.1021/ja01569a041.
  4. 1 2 Murphy, William S.; Hamrick, Phillip J.; Hauser, Charles R. (1968). "1,1-Diphenylpentane". Organic Syntheses . 48: 80. doi:10.15227/orgsyn.048.0080.
  5. Zhang, Xian-Man; Bordwell, Frederick G. (1992). "Homolytic bond dissociation energies of the benzylic carbon-hydrogen bonds in radical anions and radical cations derived from fluorenes, triphenylmethanes, and related compounds". J. Am. Chem. Soc. 114 (25): 9787–9792. doi:10.1021/ja00051a010.
  6. Blanksby, S. J.; Ellison, G. B. (2003). "Bond Dissociation Energies of Organic Molecules". Accounts of Chemical Research . 36 (4): 255–263. doi:10.1021/ar020230d. PMID   12693923.
  7. Streitwieser, Andrew; Bergman, Robert G. (2018). "Table of Bond Dissociation Energies". University of California, Berkeley . Retrieved December 30, 2021.