Difference between revisions of "Diphenylmethanol"
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===Physical=== | ===Physical=== | ||
| − | Diphenylmethanol is a white solid, insoluble in water, but soluble in organic solvents. | + | Diphenylmethanol is a white solid, insoluble in water, but soluble in organic solvents. Diphenylmethanol and benzophenone form a eutectic melting slightly below 25 °C.<ref>K. Hideko, D. P. H. Bittl, M. Fumihiro, W. Yang, M. Teruo, Journal of Photochemistry and Photobiology A: Chemistry 1995, 86, 171-176, [https://doi.org/10.1016/1010-6030(94)03942-N doi:10.1016/1010-6030(94)03942-N]</ref> |
| + | |||
| + | ===Chromatographic=== | ||
| + | It should be noted that when assessing the purity of benzophenone by TLC, that benzophenone (a likely impurity) is considerably more UV active at 254 nm than diphenylmethanol, and thus make a trace contamination seem more significant that it really is.<ref name="ramakrishna" /> | ||
| + | |||
| + | Useable TLC systems are (as measured on Merck silica gel 60 F<sub>254</sub>, visualized with 254 nm UV): | ||
| + | |||
| + | '''Eluent''': hexane/ethyl acetate, 9/1, v/v | ||
| + | : R<sub>f</sub> (diphenylmethanol) = 0.26 - 0.30 | ||
| + | : R<sub>f</sub> (benzophenone) = 0.51 | ||
| + | '''Eluent''': hexane/ethyl acetate, 1/1, v/v | ||
| + | : R<sub>f</sub> (diphenylmethanol) = 0.72 | ||
==Availability== | ==Availability== | ||
| Line 122: | Line 133: | ||
==Preparation== | ==Preparation== | ||
| − | Diphenylmethanol may be prepared by a [[Grignard reaction]] between phenylmagnesium bromide (prepared from benzyl bromide and magnesium) and [[benzaldehyde]]. | + | Diphenylmethanol may be prepared by a [[Grignard reaction]] between phenylmagnesium bromide (prepared from benzyl bromide and magnesium) and [[benzaldehyde]]. The resulting benhydrol is obtained by adding cold water/crushed ice to the reaction product.<ref>[https://www.youtube.com/watch?v=GNAfK-hKbSo Making a Secondary Alcohol Called Benzhydrol]</ref> |
| + | |||
| + | : C<sub>6</sub>H<sub>5</sub>MgBr + C<sub>6</sub>H<sub>5</sub>CHO → (C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>CH-OMgBr | ||
| + | : (C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>CH-OMgBr + H<sub>2</sub>O → (C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>CH-OH + Mg(OH)Br | ||
| + | |||
| + | Reducing [[benzophenone]] is another route. | ||
| − | + | : (C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>C=O + 2 [H] → (C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>CH-OH | |
| − | + | Reducing agents used for this reaction are: | |
| + | *[[Sodium borohydride]] with sodium hydroxide in water<ref>[https://www.youtube.com/watch?v=cPCE23MctY8 Synthesis of Benzhydrol]</ref><ref name="ramakrishna">R. Ramakrishna, ''SyntheticPage'' '''2012''', 539, [https://www.doi.org/10.1039/SP539 doi:10.1039/SP539]</ref> | ||
| + | *[[Zinc]] dust with [[sodium hydroxide]] in [[ethanol]]<ref>http://www.orgsyn.org/demo.aspx?prep=cv1p0090</ref> | ||
| + | *[[Sodium]] amalgam can also bee used. | ||
| − | [[ | + | Interestingly enough, according to one source, benzhydrol can also be obtained by reducing benzophenone using only [[sodium hydroxide]] in [[isopropanol]]. The reaction takes place under reflux, for 27 h, and the yield of this route is claimed to be 90%.<ref>[https://www.tandfonline.com/doi/full/10.1080/00397910903061043 Daniel R. Zuidema, Katherine J. Wert, Sarah L. Williams, Samuel T. Chill, Kimberly L. Holte, Nathanael K. Kokes, Novel Method of Reducing Ketones Using Sodium Hydroxide in Isopropanol, Synthetic Communications, Volume 40, 2010 - Issue 8, p. 1187-1191 ]</ref> |
Can also be prepared by hydrolyzing diphenhydramine. | Can also be prepared by hydrolyzing diphenhydramine. | ||
Latest revision as of 18:04, 5 March 2024
| Names | |
|---|---|
| IUPAC name
Diphenylmethanol
| |
| Systematic IUPAC name
Diphenylmethanol | |
| Other names
1,1-Diphenylmethanol
Benzhydrol Diphenylcarbinol Hydroxydiphenylmethane | |
| Properties | |
| C13H12O (C6H5)2CHOH | |
| Molar mass | 184.238 g/mol |
| Appearance | White solid |
| Odor | Odorless |
| Density | 1.103 g/cm3 |
| Melting point | 65–67 °C (149–153 °F; 338–340 K) |
| Boiling point | 297–298 °C (567–568 °F; 570–571 K) |
| 0.05 g/100 ml (20 °C) | |
| Solubility | Soluble in acetonitrile, chloroform, diethyl ether, ethanol, methanol |
| Solubility in ethanol | 35 g/100 ml[1] |
| Vapor pressure | 2.73·10-5 mmHg at 20 °C |
| Thermochemistry | |
| Std enthalpy of
formation (ΔfH |
-105.34 kJ/mol |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | 160 °C (320 °F; 433 K) |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
5,000 mg/kg (rat, oral) |
| Related compounds | |
| Related compounds
|
Benzyl alcohol Triphenylmethanol |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Diphenylmethanol or benzhydrol is the organic compound with the formula C13H12O.
Contents
Properties
Chemical
Diphenylmethanol can be oxidized to benzophenone.
Physical
Diphenylmethanol is a white solid, insoluble in water, but soluble in organic solvents. Diphenylmethanol and benzophenone form a eutectic melting slightly below 25 °C.[2]
Chromatographic
It should be noted that when assessing the purity of benzophenone by TLC, that benzophenone (a likely impurity) is considerably more UV active at 254 nm than diphenylmethanol, and thus make a trace contamination seem more significant that it really is.[3]
Useable TLC systems are (as measured on Merck silica gel 60 F254, visualized with 254 nm UV):
Eluent: hexane/ethyl acetate, 9/1, v/v
- Rf (diphenylmethanol) = 0.26 - 0.30
- Rf (benzophenone) = 0.51
Eluent: hexane/ethyl acetate, 1/1, v/v
- Rf (diphenylmethanol) = 0.72
Availability
Diphenylmethanol is sold by chemical suppliers.
Preparation
Diphenylmethanol may be prepared by a Grignard reaction between phenylmagnesium bromide (prepared from benzyl bromide and magnesium) and benzaldehyde. The resulting benhydrol is obtained by adding cold water/crushed ice to the reaction product.[4]
- C6H5MgBr + C6H5CHO → (C6H6)2CH-OMgBr
- (C6H6)2CH-OMgBr + H2O → (C6H6)2CH-OH + Mg(OH)Br
Reducing benzophenone is another route.
- (C6H6)2C=O + 2 [H] → (C6H6)2CH-OH
Reducing agents used for this reaction are:
- Sodium borohydride with sodium hydroxide in water[5][3]
- Zinc dust with sodium hydroxide in ethanol[6]
- Sodium amalgam can also bee used.
Interestingly enough, according to one source, benzhydrol can also be obtained by reducing benzophenone using only sodium hydroxide in isopropanol. The reaction takes place under reflux, for 27 h, and the yield of this route is claimed to be 90%.[7]
Can also be prepared by hydrolyzing diphenhydramine.
Projects
- Synthesis of Modafinil/Armodafinil, Adrafinil
- Synthesis of Diphenhydramine
Handling
Safety
Diphenylmethanol is an irritant to the eyes, skin and respiratory system.
Storage
In closed bottles.
Disposal
No special disposal is required as it's not very toxic.
References
- ↑ Cohen; Recueil des Travaux Chimiques des Pays-Bas; vol. 38; (1919); p. 88
- ↑ K. Hideko, D. P. H. Bittl, M. Fumihiro, W. Yang, M. Teruo, Journal of Photochemistry and Photobiology A: Chemistry 1995, 86, 171-176, doi:10.1016/1010-6030(94)03942-N
- ↑ 3.0 3.1 R. Ramakrishna, SyntheticPage 2012, 539, doi:10.1039/SP539
- ↑ Making a Secondary Alcohol Called Benzhydrol
- ↑ Synthesis of Benzhydrol
- ↑ http://www.orgsyn.org/demo.aspx?prep=cv1p0090
- ↑ Daniel R. Zuidema, Katherine J. Wert, Sarah L. Williams, Samuel T. Chill, Kimberly L. Holte, Nathanael K. Kokes, Novel Method of Reducing Ketones Using Sodium Hydroxide in Isopropanol, Synthetic Communications, Volume 40, 2010 - Issue 8, p. 1187-1191
