Biphenyl, reaction

Fig. 3 Effect of SI/AI2 Ratio of HM Zeolite on Isopropylation of Biphenyl Reaction conditions HM Ig, Biphenyl 50 mmol, Propene 100 mmol, 4 h.

Figure 5 Effect of the dealumination on the product distribution of encapsulated DIP isomers inside pores and of bulk products in the isopropylation of biphenyl. Reaction conditions are the same as in Figure 3.

Figure 6 Effect of propylene pressure on the yield of 4,4 - and 3,4 -DIPB in the isopropylation of biphenyl. Reaction conditions biphenyl, 400 mmol HM(220), 2 g propylene pressure, 0.1-0.8 MPa temperature, 250 °C.

NOTE The anthracene and naphthalene reactions were performed at -78 °C for 15-30 min, and the biphenyl reactions were performed at -33 °C for 15-30 min. 

Figure C3.2.10.(a) Dependence of electron transfer rate upon reaction free energy for ET between biphenyl radical anions and various organic acceptors. Experiments were perfonned with the donors and acceptors frozen into...

Figure C3.2.11. Log of the ET rate (A) against (l/s p-l/E ) for tire bis(biphenyl) cliromium self-exchange reaction. From 1341.

It should be noted that reported kinetic data on the nitration of biphenyl are hmited to one rate constant for reaction in 68-3 % sulphuric acid at 25 °C k = 0-92 1 mol s i relative rate, 15-8). Until they have been extended the above discussion must be regarded as provisional. 

The oxidative homocoupling of benzene with Pd(OAc)2, generated in situ from PdCl2 and. AcONa, affords biphenyl in 81% yield. In the absence of AcONa, no reaction took place. Pd(OAc)2 itself is a good reagent for the coupling[324-326]. The scope of the reaction has been studied[327,328]. 

The backbone of poly(phenylene oxide)s is cleaved under certain extreme reaction conditions. Lithium biphenyl reduces DMPPO to low molecular weight products in the dimer and trimer molecular weight range (20) and converts poly(2,6-diphenyl-l,4-phenylene oxide) to 3,5-diphenylphenol in 85% yield (21) (eq. 4). 

Hydrogenation Reactions. Hydrogen over a nickel, platinum, or paladium catalyst can partially or totally saturate the aromatic ring. Thermal hyrogenolysis of toluene yields benzene, methane, and biphenyl. 

Pyrolysis. Benzene undergoes thermal dehydrocondensation at high temperatures to produce small amounts of biphenyls and terphenyls (see Biphenyl AND terphenyls). Before the 1970s most commercial biphenyl was produced from benzene pyrolysis. In a typical procedure benzene vapors are passed through a reactor, usually at temperatures above 650°C. The decomposition of benzene iato carbon and hydrogen is a competing reaction at temperatures of about 750°C. Biphenyls are also formed when benzene and ethylene are heated to 130—160°C ia the presence of alkaH metals on activated AI2O3 (33). 

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