502-86-3

Upstream product

• 106-42-3 para-xylene 
• 2348-52-9 4-methylbenzyl radical 
• 7567-83-1 <2.2>Paracyclophane-1,10-dione 
• 623-25-6 p-Xylylene dichloride 
• 17095-21-5 4-<(trimethylsilyl)methyl>benzoic acid 
• 17993-96-3 p-<(Trimethylsilyl)methyl>benzyl alcohol 
• 875556-32-4 (4-[(trimethylsilyl)methyl]phenyl)methyl acetate 
• 22176-80-3 <2.2>Metaparacyclophan-2,9-dion 

Downstream Products

• 62855-80-5 1,4-bis(thiocyanatomethyl)benzene 
• 623-24-5 1,4-bis(bromomethyl)benzene 
• 69386-99-8 terephthalaldehyde oxime 
• 30362-89-1 p-bis(iodomethyl)benzene 
• 99848-46-1 4-(chloromethyl)benzaldehyde oxime 
• 1633-22-3 [2.2]Paracyclophan 
• 107171-17-5 4,8-dimethyl<2.2>paracyclophane 
• 283-80-7 [2.2.2]paracyclophane 
• 1524-14-7 4-methylbenzyl trifluoroacetate 
• 623-27-8 terephthalaldehyde, 

Relevant academic research and scientific papers

Formation of p-xylylene from p-xylene by a two-photon process and hexamethyl Dewar benzene from hexamethylbenzene by a one-photon process at 193 nm

While studying a series of methyl-substituted benzenes, C6H 6-n(CH3)n with n = 2, 3, 4, 6, and perfluorobenzene in the gas phase using 193-nm laser flash photolysis, we observed the formation of p-xylylene (benzoquinodimethane) due to the elimination of two hydrogen atoms as a result of a two-photon process. The results were explained in terms of an intermediate hot molecule formed by internal conversion which finally led to the ground electronic state. Quadratical dependencies on the photoproducts were observed for toluene, xylene, mesitylene, and perfluorobenzene in the presence of a foreign gas, while linear dependencies were observed for durene and hexamethylbenzene. Dewar-type benzene was detected from photolysis of hexamethylbenzene.

Room temperature observation of p-xylylenes by 1H NMR and evidence for diradical intermediates in their oligomerization

p-Quinodimethanes (p-QDMs) are reactive molecules that have been invoked as transient intermediates in a number of reactions. Dilute solutions of benzene-based p-QDMs, p-xylylene (1), α-methyl-p-xylylene (10), and 2,5-dimethyl-p-xylylene (11) can be prepared by fluoride-induced elimination of trimethylsilyl acetate from the appropriate precursor. It has been found that these solutions are stable enough to allow these reactive p-QDMs to be observed by 1H NMR spectroscopy at room temperature. For the first time, the 13C NMR spectrum of p-QDM 1 was observed. After several hours at room temperature, these p-QDMs form dimers, trimers, and insoluble oligomers. Formation of trimers provides evidence that p-QDMs 1, 10, and 11 dimerize by a stepwise mechanism involving dimeric diradicals as intermediates.

Mechanistic studies on the photogeneration of o-and p-xylylenes from aαα′-dichloroxylenes

Two-colour two-laser techniques have unambiguously proved that photolysis of the o-/p-(chloromethyl)benzyl radical leads to the sequential two-photon generation of o-/p-xylylene from α,α′-dichloro-o-/p-xylene.

1,3-Didehydrobenzol (meta-Benzin)

Keywords: Ab-initio-Rechnungen; 1,3-Didehydrobenzol; Diradikale; Photolyse; Thermolyse

1,4-Dicarbonyl-2,5-cyclohexadiene

The mechanism of the photolysis of paracyclophane-1,10-dione (9) was investigated in solution and in argon matrices.The first step of the photolysis involves α-cleavage of the cyclophane yielding a diradical 11 which could be trapped by ethanol.In argon at 10 K the diradical rapidly splits into p-xylylene (10) and 1,4-dicarbonyl-2,5-cyclohexadiene (7) and therefore was not directly observed by spectroscopic methods.The bisketene 7 was characterized by comparison of the experimantal and calculated IR spectrum. - Keywords: Ketenes / Matrix isolation / Calculations, ab initio