«P-DCB-1»: Synthesis of paradichlorobenzene
TECHNOLOGY OF THE SYNTHESIS OF PARADICHOLOROBENZENE
Application area:
Paradichlorobenzene (p-DCB) is a valuable product of industrial organochlorine synthesis, is used as a deodorant, insecticide, antiseptic, lacquer solvent, preservative in the leather industry, is a raw material for the production of intermediates, dyes and pharmaceuticals.
Recently, there has been an increase in the demand for p-DCB, which is associated with its use as a raw material for the production of highly structural thermoplastics – polyphenyl sulfides (PPS).
In the US, more than 50% of p-DCB produced is used to produce PFC. Part of the need for p-DCB is covered by its isolation from the bottoms of chlorobenzene (CB) production. However, this applies only to countries with significant CB capacities. In other cases, it becomes necessary to create special production facilities for p-DCB.
The essence of the process:
Paradichlorobenzene is obtained by chlorination of benzene or monochlorobenzene in the temperature range of 55÷60°C using a NaY type zeolite catalyst.
Technology Description:
Schematic diagram of pilot production of paradichlorobenzene:
D-1 – drum of chlorobenzene; P-2 – chlorobenzene dosing pump; A-3/1 – adsorber for drying chlorine; A-3/2 – adsorber for drying chlorobenzene; R-4 – chlorination reactor; F-5/1 – filter; F-5/2 – filtrate capacity; D-6 – absorption capacity; E-7 – vat boiler; C-8 – distillation column; E-9 – capacitor; D-10 – distillate drum; D-11 – circulation drum; P-12 – circulation pump; E-13 – air cooler
Advantages:
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High selectivity of the process (78%) with complete conversion of monochlorobenzene.
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Possibility of separating p-DCB from a mixture of its isomers.