The Synthetic Routes of 2,7-Dibromo-9,9'-spiro-bifluorene

The synthesis of 2,7-dibromo-9,9'-spiro-bifluorene is an important process in the chemical industry, as this compound is used in a variety of applications, including as a polymerization initiator, a photosensitizer in photovoltaic cells, and as a fluorescent whitening agent in textiles and papers.

There are several synthetic routes to 2,7-dibromo-9,9'-spiro-bifluorene that have been developed over the years.
One of the most common methods involves the reaction of 2,3-dibromopropene with 2,3-dibromopryene in the presence of a phase transfer catalyst, such as benzenesulfonic acid.
This reaction results in the formation of a mixture of the desired product and various byproducts, which must be separated and purified before use.

Another synthetic route involves the reaction of 9,9'-spiro-fluorene-2,7-diyl dichloride with 2-bromomethyl-6-chloro-1,3,3-trimethylindane in the presence of a base, such as potassium hydroxide.
This reaction results in the formation of the desired product, along with some unwanted side products that must be removed through purification.

A third synthetic route involves the reaction of 2,2-dimethyl-7,8-dibromo-7,8-dihydro-spirobenzofuran with 9,9'-spiro-fluorene-2,7-diyl iodide in the presence of a Lewis acid catalyst, such as aluminum chloride.
This reaction results in the formation of the desired product, along with some unwanted side products that must be removed through purification.

Once the desired 2,7-dibromo-9,9'-spiro-bifluorene has been synthesized, it can be further purified and characterized through a variety of techniques, including nuclear magnetic resonance (NMR) spectroscopy, high-performance liquid chromatography (HPLC), and mass spectrometry.
The resulting product must meet certain purity and quality standards before it can be used in its desired applications.

Overall, the synthetic routes to 2,7-dibromo-9,9'-spiro-bifluorene are varied and include several methods that have been developed over the years.
Each route has its own advantages and disadvantages, and the selection of the appropriate route will depend on factors such as the desired yield, the purity of the final product, and the cost of the synthesis.
The continued development of new synthetic methods and the optimization of existing methods will continue to be important in the chemical industry as the demand for 2,7-dibromo-9,9'-spiro-bifluorene and other chemical compounds continues to grow.