The Synthetic Routes of 9,9'-(1,3-Phenylene)bis-9H-carbazole

The synthesis of 9,9'-(1,3-Phenylene)bis-9H-carbazole, also known as PCB (Poly(dicyclohexylphosphine oxide)) is an important synthetic route in the chemical industry.
This synthetic route is commonly used to prepare this compound, which is widely used as a plasticizer in the production of PVC (Polyvinyl Chloride) plastics.

The synthesis of PCB can be accomplished through several different methods, each with its own advantages and disadvantages.
The most commonly used synthetic routes are the phosphorylation of bisphenol A and the phosphorylation of o-dichlorobenzene.

The phosphorylation of bisphenol A is a multi-step process that involves the conversion of bisphenol A into bis-(dicyclohexylphosphino)diphenylcarbazide.
This intermediate is then converted into PCB through a series of additional steps.
This route is considered to be more cost-effective than the phosphorylation of o-dichlorobenzene, but it requires the use of hazardous reagents and is associated with a higher waste generation.

On the other hand, the phosphorylation of o-dichlorobenzene is a more environmentally friendly process that involves the direct phosphorylation of o-dichlorobenzene to produce PCB.
This route is more selective and requires less chemicals and reagents, but it is generally more expensive and has a lower yield compared to the phosphorylation of bisphenol A.

Recently, researchers have developed a new and more efficient route for the synthesis of PCB, based on the phosphorylation of 4-chlorophenyl benzene using a phosphine oxide as a reagent.
This new route is considered to be a greener alternative to the traditional methods, as it avoids the use of o-dichlorobenzene, which is a widely recognized environmental pollutant.
Additionally, this new route is simpler, more cost-effective and has a higher yield compared to the existing methods.

Overall, the synthesis of PCB is a significant process in the chemical industry and several synthetic routes have been developed to produce this compound.
The choice of synthetic route depends on the desired yield, cost, and environmental impact of the process.
The phosphorylation of bisphenol A and o-dichlorobenzene have been the most commonly used methods, but recent advances have been made to develop more efficient and greener methods for the production of PCB.
The new route based on the phosphorylation of 4-chlorophenyl benzene using a phosphine oxide as a reagent is considered to be a promising alternative method for the synthesis of PCB.