O-Dichlorobenzene solvent

The regioselectivity of the cydoaddition of N-methylazomethine ylide to C70 was daimed to be slightly affected using microwave irradiation as the source. By choosing an appropriate solvent (o-dichlorobenzene, ODCB) and the emitted microwave power, the ratio la lb is modified from 50 50 to 45 55 [26, 59] (Eq. (63) and Tab. 3.25). 

Solvents o-dichlorobenzene, triisopropylbenzene Yields 41-87% depending on C=C config. 

A11 reactions were carried out under N2, using anhydrous conditions, with 5% nucleophile. Mole % relative to substrate. Isolated Yields. Toluene solvent. Chlorobenzene solvent. o-Dichlorobenzene solvent. 

Photochemical butterfly-like E — Z photoisomerization of a bis(crown ether) azobenzene derivative 354 was found to be thermally reversible and the stereoisomers exhibit unique contrasting behaviour in the presence of metal ions.1108 The concentration of the Z-isomer in the photostationary state was noticeably enhanced by the addition of K+, Rb + or Cs +, because the corresponding Z-complex achieved a stable sandwich geometry (Scheme 6.162). As a result, the cations could be selectively extracted by the Z-derivative from an aqueous phase to an organic solvent (o-dichlorobenzene), whereas no complexation (i.e. no transfer) took place in the case of the E-isomer. 

Fig. 2. Yields of the products in the oxidation of benzaldehyde. The lines represent the calculated results and the point are the experimental data. [Benzaldehyde]o = 0.640 mole l 1 temperature, 43°C solvent, o-dichlorobenzene oxygen pressure, 1.25 atm. O, 02 absorbed , [CgHsCOsH] C6H5C02H.

Fig. 1. Microphotograph of a PC film containing 1 wt.% of TTT TCNQ. Cast temperature 120° C, solvent o-dichlorobenzene.

Diels-Alder cycloaddition of equimolar amounts of fullerene and exocyclic diene 39 incorporated in norbomene framework gave after 30 min of milling in custom-built ball-mill cycloadduct 40 in 14% yield (Scheme 7.10) [17]. Control experiments carried out in o-dichlorobenzene solution at 140°C gave 40 in 40% yield, while at 70°C adduct 40 was formed in 92% yield. Although these results favor solution chemistry, it is an important information that this reaction could be also carried in solvent-free conditions, without the use of highly toxic chlorinated aromatic solvents (o-dichlorobenzene). 

In the USA, 150,000 t benzene were used in 1976 for the production of chlorobenzene [27]. It is assumed in western Europe that 500,000 t benzene will have been used in 1979 as initial product for chloro- and nitrobenzene [3]. Based on these figures, the annual world production of chlorinated benzenes can be estimated at 600,000-800,000 t. Direct chlorination of benzene with chlorine gas is effected on a continuous basis in the presence of catalysts, such as aluminium, mercury, iron, sulphur chlorides or molybdenum chloride [32, 36, 43], following which the mixture is separated and purified by washing, chemical treatment and distillation operations. Chlorobenzene is used mainly for the production of phenol, chloronit-robenzenes, DDT, and as a solvent, o-dichlorobenzene is a solvent, whereas p-dichlorobenzene is used as an intermediate or (in addition to naphthalene) as a mothproofing agent [292]. 

Figure 8.14 Examples of the universal calibration curve for GPC. (a) Universal calibration for tetrahydrofuran solution at ambient temperature , linear polystyrene , polybutadiene O, branched polystyrene x, polymethyl methacrylate A, styrene/ methyl methacrylate copolymer , poly(phenyl siloxane). (b) Universal calibration for various types of polyethylene. Solvent, o-dichlorobenzene at 130°C. , linear polyethylene fractions open symbols, branched polyethylene fractions. (From Ref 6.)...

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