�ber eine verbesserte Darstellungsweise des Terephtalaldehyds

Hönig, M.

doi:10.1007/bf01516765

Cited by 10 publications

(1 citation statement)

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“…Cooling on an ice-bath gave fine solid precipitate of -tetrabromo-p-xylene (3.8 g, 61%), mp 169-170 °C (lit. [20] FVP of the title compound (2.2 g, 600 °C, 8.0 × 10 -1 Torr, inlet 95-100 °C, 2.0 g magnesium) gave as main product a polymeric material coated in the cold trap, with a trace of a liquid which consisted of p-xylene (1%), toluene (0.6%) and benzene (0.8%). As the polymer was insoluble in conventional solvents, it was simply peeled off from the cold trap.…”

Section: Preparation Of -Tetrabromo-p-xylene 12mentioning

confidence: 99%

Flash vacuum pyrolysis of benzylidene halides, benzotrihalides and aryl halides over magnesium

Aitken

Hodgson²,

Oyewale

2017

Journal of Analytical and Applied Pyrolysis

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Flash vacuum pyrolysis at 600 C through glass wool coated with freshly sublimed magnesium is examined as a preparative method for dehalogenative coupling in organic synthesis. Substituted benzylidene chlorides give predominantly the corresponding stilbenes and in some cases these are readily isolated in pure form. With an ortho-halogen substituent, additional cyclisation gives phenanthrenes but the method is not compatible with the presence of several reactive groups. An orthomethoxy substituent leads to unexpected formation of mono-and dimethyl products. With 1,4-bis(dihalomethyl)benzenes, halogenated polymers are deposited directly from the gas phase via generation of halogenated p-xylylenes. The 1,2-and 1,3-isomers lead respectively to benzocyclobutadiene, isolated as a dimer, and to pyrene. The 1,4-bis(trihalomethyl)benzenes give more highly halogenated polymers directly from the gas phase via halogenated p-xylylenes. While halobenzenes generally give the corresponding benzenes and biphenyls, 1,2-dihalobenzenes additionally produce triphenylene in preparatively useful yield by a process not involving intermediacy of free benzyne.

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Section: Preparation Of -Tetrabromo-p-xylene 12mentioning

confidence: 99%