Benzene benzene

NlTRDPROPANE NITRO-ETHANE NITR3-METHANE TOLUENE BENZENE BENZENE BENZENE BENZENE BENZENE BENZENE BENZENE... 

Ethyl- ij-Propyl- -Butyl-Benzene Toluene benzene benzene benzene... 

Benzene Pentane Benzene Benzene Benzene Glycerol Ethylene Glycol Propylene Glycol... 

If the substance is found to be far too soluble in one solvent and much too insoluble in another solvent to allow of satisfactory recrystallisation, mixed solvents or solvent pairs may frequently be used with excellent results. The two solvents must, of course, be completely miscible. Recrystallisation from mixed solvents is carried out near the boiling point of the solvent. The compound is dissolved in the solvent in which it is very soluble, and the hot solvent, in which the substance is only sparingly soluble, is added cautiously until a slight turbidity is produced. The turbidity is then just cleared by the addition of a small quantity of the first solvent and the mixture is allowed to cool to room temperature crystals will separate. Pairs of liquids which may be used include alcohol and water alcohol and benzene benzene and petroleum ether acetone and petroleum ether glacial acetic acid and water. 

The strained undecacyclic pagodane framework was obtained in a series of 14 one-pot operations with an overall yield up to 24% from commercial isodrin. The key steps are (i) a benzene-benzene [6 -I- 6]photocycloaddition, and (ii) a domino Diels-Alder reaction. 

Miscellaneous Sources of Benzene. Benzene has been recovered from coal tar. The lowest boiling fraction is extracted with caustic soda to remove tar acids. The base washed oil is then distiUed and further purified by hydrodealkylation. 

The electrophilic substitution of thiophene is much easier than that of benzene thus, thiophene is protonated in aqueous sulphuric acid about 10 times more rapidly than benzene, and it is brominated by molecular bromine in acetic acid about 10 times more rapidly than benzene. Benzene in turn is between 10 and lo times more reactive than an uncharged pyridine ring to electrophilic substitution. 

Aminopyridine [504-24-5] M 94.1, m 160°, b 180 /12-13mm, pK -6.55, pKj . (9.18). Crystd from benzene/EtOH, then recrystd twice from water, crushed and dried for 4h at 105° [Bates and Hetzer J Res Nat Bur Stand 64A 427 I960], Has also been crystd from EtOH, benzene, benzene/pet ether, toluene and sublimes in vacuum. 

Nitrophthalic anhydride [641-70-3] M 193.1, m 164 . Crystd from benzene, benzene/pet ether, acetic actic or acetone. Dried at 100°. 

Tetrachlorobenzene [95-94-3] M 215.9, m 139.5-140.5 , b 240 /760mm. Crystd from EtOH, ether, benzene, benzene/EtOH or carbon disulfide. 

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