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Many different solvents are suitable, including sulfolane (C 4 H 8 O 2 S), furfural (C 5 H 4 O 2), tetraethylene glycol (C 8 H 18 O 5), dimethylsulfoxide (C 2 H 6 OS), and N-methyl-2-pyrrolidone (C 5 H 9 NO). Below is a schematic flow diagram of one method, involving extractive distillation, for extraction of the BTX aromatics from a catalytic ...
The process, which is catalyzed by platinum supported by aluminium oxide, is exemplified in the conversion methylcyclohexane (a naphthene) into toluene (an aromatic). [2] Dehydrocyclization converts paraffins (acyclic hydrocarbons) into aromatics. [3] A related aromatization process includes dehydroisomerization of methylcyclopentane to benzene:
Xylenes are produced mainly as part of the BTX aromatics (benzene, toluene, and xylenes) extracted from the product of catalytic reforming known as reformate. Several million tons are produced annually. [3] In 2011, a global consortium began construction of one of the world's largest xylene plants in Singapore. [5]
The aromatic products of the reaction are then separated from the reaction mixture (or reformate) by extraction with any one of a number of solvents, including diethylene glycol or sulfolane, and benzene is then separated from the other aromatics by distillation. The extraction step of aromatics from the reformate is designed to produce ...
The production of p-xylene is industrially significant, with annual demand estimated at 37 million tons in 2014, and still on the increase. [12] [13] p-Xylene is produced by catalytic reforming of petroleum naphtha as part of the BTX aromatics (benzene, toluene and the xylene isomers) extracted from the catalytic reformate.
Transalkylation is employed in the commercial production of aromatics beyond the usual BTX feedstocks. For example, 4- tert -butylphenol is produced in part via two transalkylation reactions. [ 7 ] In one example, tert -butylphenyl ether is isomerized to the phenol:
The naphtha is a mixture of very many different hydrocarbon compounds. It has an initial boiling point of about 35 °C and a final boiling point of about 200 °C, and it contains paraffin, naphthene (cyclic paraffins) and aromatic hydrocarbons ranging from those containing 6 carbon atoms to those containing about 10 or 11 carbon atoms.
The Béchamp reduction (or Béchamp process) is a chemical reaction that converts aromatic nitro compounds to their corresponding anilines using iron as the reductant: [1] 4 C 6 H 5 NO 2 + 9 Fe + 4 H 2 O → 4 C 6 H 5 NH 2 + 3 Fe 3 O 4. This reaction was once a major route to aniline, but catalytic hydrogenation is the preferred method. [2]