Benzil (i.e. Bz2, systematically known as 1,2-diphenylethane-1,2-dione) is the organic compound with the formula (C6H5CO)2, generally abbreviated (PhCO)2. This yellow solid is one of the most common diketones. Its main use is as a photoinitiator in polymer chemistry.[4]
The compound's most noteworthy structural feature is the long carbon-carbon bond of 1.54 Å, which indicates the absence of pi-bonding between the two carbonyl centers. The PhCO centers are planar, but the pair of benzoyl groups are twisted with respect to the other with a dihedral angle of 117°.[5] In less hindered analogues (glyoxal, biacetyl, oxalic acid derivatives), the (RCO)2 group adopts a planar, anti-conformation.
Applicationsedit
Most benzil can be used as a photoinitiator in the free-radical curing of polymer networks. It absorbs ultraviolet radiation at a wavelength of 260 nm, leading to decomposition with formation of free-radical species and formation of cross-links within the material. However, it is a relatively poor photoinitiator, and is seldom used. It undergoes photobleaching, which allows the curing light to reach deeper layers of the material on longer exposure.[6]Acetal derivatives, such as 2,2-dimethoxy-2-phenylacetophenone, have better properties for this application.[6]
Benzil is a potent inhibitor of human carboxylesterases, enzymes involved in the hydrolysis of carboxylesters and many clinically used drugs.[7]
^Hardo Siegel, Manfred Eggersdorfer "Ketones" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, 2002 by Wiley-VCH, Weinheim. doi:10.1002/14356007.a15_077
^Quang. Shen, Kolbjoern. Hagen "Gas-phase molecular structure and conformation of benzil as determined by electron diffraction" J. Phys. Chem., 1987, 91 (6), pp 1357–1360. doi:10.1021/j100290a017.
^ abGreen, W. Arthur (2010-04-22). Industrial Photoinitiators: A Technical Guide. p. 31. ISBN9781439827468. Retrieved 2022-05-21.
^Wadkins. R. M. et al "Identification and characterization of novel benzil (diphenylethane-1,2-dione) analogues as inhibitors of mammalian carboxylesterases. J. Med. Chem., 2005 48 pp 2906–15.
^Depreux, P.; Bethegnies, G.; Marcincal-Lefebvre, A. (1988). "Synthesis of benzil from benzoin with copper(II) acetate". Journal of Chemical Education. 65 (6): 553. Bibcode:1988JChEd..65..553D. doi:10.1021/ed065p553.
^Bi, Xiaoxin; Wu, Lintao; Yan, Chaoguo; Jing, Xiaobi; Zhu, Hongxiang (2011). "One-Pot Synthesis Benzils from Aldehydes Via Nhc-Catalyzed Benzoin Dimerization Under Metal-Free Conditions in Water". Journal of the Chilean Chemical Society. 56 (2): 663. doi:10.4067/S0717-97072011000200008.
January 01, 1970
benzil, confused, with, benzyl, systematically, known, diphenylethane, dione, organic, compound, with, formula, c6h5co, generally, abbreviated, phco, this, yellow, solid, most, common, diketones, main, photoinitiator, polymer, chemistry, names, preferred, iupa. Not to be confused with benzyl Benzil i e Bz2 systematically known as 1 2 diphenylethane 1 2 dione is the organic compound with the formula C6H5CO 2 generally abbreviated PhCO 2 This yellow solid is one of the most common diketones Its main use is as a photoinitiator in polymer chemistry 4 Benzil Names Preferred IUPAC name Diphenylethanedione Systematic IUPAC name 1 2 Diphenylethane 1 2 dione Other names Diphenylethane 1 2 dioneBenzilDibenzoylBibenzoylDiphenylglyoxal Identifiers CAS Number 134 81 6 Y 3D model JSmol Interactive imageInteractive image Beilstein Reference 608047 ChEBI CHEBI 51507 Y ChEMBL ChEMBL189886 Y ChemSpider 8329 Y ECHA InfoCard 100 004 689 EC Number 205 157 0 PubChem CID 8651 RTECS number DD1925000 UNII S85X61172J Y CompTox Dashboard EPA DTXSID3044380 InChI InChI 1S C14H10O2 c15 13 11 7 3 1 4 8 11 14 16 12 9 5 2 6 10 12 h1 10H YKey WURBFLDFSFBTLW UHFFFAOYSA N YInChI 1 C14H10O2 c15 13 11 7 3 1 4 8 11 14 16 12 9 5 2 6 10 12 h1 10HKey WURBFLDFSFBTLW UHFFFAOYAZ SMILES O C C O c1ccccc1 c2ccccc2c1ccccc1C O C O c2ccccc2 Properties Chemical formula C 14H 10O 2 Molar mass 210 232 g mol 1 Appearance yellow crystalline powder Density 1 23 g cm3 solid 1 255 g cm3 x ray Melting point 94 0 to 96 0 C 201 2 to 204 8 F 367 1 to 369 2 K Boiling point 346 0 to 348 0 C 654 8 to 658 4 F 619 1 to 621 1 K Solubility in water insoluble Solubility in ethanol soluble Solubility in diethyl ether soluble Solubility in benzene soluble Magnetic susceptibility x 118 6 10 6 cm3 mol Structure Crystal structure P31 221 1 Dipole moment 3 8 D 2 Hazards Occupational safety and health OHS OSH Main hazards Irritant GHS labelling Pictograms Signal word Warning Hazard statements H315 H319 H335 Precautionary statements P261 P264 P271 P280 P302 P352 P304 P340 P305 P351 P338 P312 P321 P332 P313 P337 P313 P362 P403 P233 P405 P501 NFPA 704 fire diamond 210 Lethal dose or concentration LD LC LD50 median dose gt 3 g kg mouse oral 3 Related compounds Related diketones diacetyl Related compounds benzophenoneglyoxalbibenzil Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references Contents 1 Structure 2 Applications 2 1 Reactions 3 Preparation 4 ReferencesStructure editThe compound s most noteworthy structural feature is the long carbon carbon bond of 1 54 A which indicates the absence of pi bonding between the two carbonyl centers The PhCO centers are planar but the pair of benzoyl groups are twisted with respect to the other with a dihedral angle of 117 5 In less hindered analogues glyoxal biacetyl oxalic acid derivatives the RCO 2 group adopts a planar anti conformation Applications editMost benzil can be used as a photoinitiator in the free radical curing of polymer networks It absorbs ultraviolet radiation at a wavelength of 260 nm leading to decomposition with formation of free radical species and formation of cross links within the material However it is a relatively poor photoinitiator and is seldom used It undergoes photobleaching which allows the curing light to reach deeper layers of the material on longer exposure 6 Acetal derivatives such as 2 2 dimethoxy 2 phenylacetophenone have better properties for this application 6 Benzil is a potent inhibitor of human carboxylesterases enzymes involved in the hydrolysis of carboxylesters and many clinically used drugs 7 Reactions edit Benzil is a standard building block in organic synthesis It condenses with amines to give diketimine ligands A classic organic reaction of benzil is the benzilic acid rearrangement in which base catalyses the conversion of benzil to benzilic acid This reactivity is exploited in the preparation of the drug phenytoin Benzil also reacts with 1 3 diphenylacetone in an aldol condensation to give tetraphenylcyclopentadienone Preparation editBenzil is prepared from benzoin for example with copper II acetate 8 PhC O CH OH Ph 2 Cu2 PhC O C O Ph 2 H 2 Cu Other suitable oxidizing agents such as nitric acid HNO3 are used routinely Iron III chloride FeCl3 can be used as an inexpensive catalyst for this chemical conversion 9 References edit Acta Crystallogr B43 398 1987 Spectrochim Acta A60 8 9 1805 2004 Benzil Hardo Siegel Manfred Eggersdorfer Ketones in Ullmann s Encyclopedia of Industrial Chemistry Wiley VCH 2002 by Wiley VCH Weinheim doi 10 1002 14356007 a15 077 Quang Shen Kolbjoern Hagen Gas phase molecular structure and conformation of benzil as determined by electron diffraction J Phys Chem 1987 91 6 pp 1357 1360 doi 10 1021 j100290a017 a b Green W Arthur 2010 04 22 Industrial Photoinitiators A Technical Guide p 31 ISBN 9781439827468 Retrieved 2022 05 21 Wadkins R M et al Identification and characterization of novel benzil diphenylethane 1 2 dione analogues as inhibitors of mammalian carboxylesterases J Med Chem 2005 48 pp 2906 15 Depreux P Bethegnies G Marcincal Lefebvre A 1988 Synthesis of benzil from benzoin with copper II acetate Journal of Chemical Education 65 6 553 Bibcode 1988JChEd 65 553D doi 10 1021 ed065p553 Bi Xiaoxin Wu Lintao Yan Chaoguo Jing Xiaobi Zhu Hongxiang 2011 One Pot Synthesis Benzils from Aldehydes Via Nhc Catalyzed Benzoin Dimerization Under Metal Free Conditions in Water Journal of the Chilean Chemical Society 56 2 663 doi 10 4067 S0717 97072011000200008 Retrieved from https en wikipedia org w index php title Benzil amp oldid 1196862408, wikipedia, wiki, book, books, library,
