Background and overview[1-2]
Tetraphenylporphine (hereinafter referred to as TPP) is an important luminescent material and a raw material for the synthesis of metalloporphyrins. The Adler method is recognized as the best method for synthesizing tetraphenylporphin. This method uses pyrrole and benzaldehyde as reaction raw materials, and reacts in refluxing propionic acid to synthesize TPP. However, the TPP yield based on pyrrole obtained by this method is less than 20%, and it contains 5 to 10% of the impurity tetraphenylporphine (hereinafter referred to as TPC). In order to remove TPC impurities mixed in TPP, subsequent researchers made a lot of improvements to the Adler method, mainly focusing on two directions: (1) Dissolve TPP containing TPC impurities in benzene, dimethyl sulfoxide, dimethyl sulfoxide, into organic solvents such as methyl chloride and chloroform, and then use chromatographic column separation to remove TPC. (2) After dissolving TPP containing TPC impurities in a certain organic solvent, add a certain amount of weak chemical oxidants such as 2,3,5,6-tetrachlorobenzoquinone, 2,3-dichloro-5,6- Dicyanoquinone and the like oxidize TPC to TPP and remove TPC. Since the solubility of TPP and TPC in organic and inorganic solvents is very small, whether it is a chromatographic column method or a method of adding chemical oxidants, it requires a large amount of solvent separation, many processes, large solvent losses, high production costs, and is not suitable for industry. large-scale production. Moreover, these methods all consider the synthesis of TPP from the perspective of how to purify it, but few consider the synthesis of TPP from the perspective of improving the reaction yield, resulting in a low yield of TPP based on pyrrole, and pyrrole is expensive. It is an important cost factor in the production of TPP, which also leads to the high production cost of existing synthesis methods and is not suitable for industrial large-scale production.
Apply[1-2]
Tetraphenylporphine (hereinafter referred to as TPP) is an important luminescent material and a raw material for the synthesis of metalloporphyrins. Application examples are as follows: To prepare μ-oxytetraphenylbimetalloporphyrin, use tetraphenylporphine and divalent metal salt as raw materials, and continuously feed oxygen-containing gas to make tetraphenylporphine and divalent metal salt dissolve in the solvent. The metallization reaction is carried out in the medium to generate tetraphenyl trivalent monometallic porphyrin (TPPMIII-X), and then the TPPMIII-X is subjected to a continuous bimetallation reaction in an alkaline environment to obtain a reaction liquid. The reaction liquid is cooled, crystallized, After filtration and washing, μ-oxotetraphenylbimetalloporphyrin product is obtained. The invention has the advantages of high yield, high reaction efficiency, low energy consumption, safety and environmental protection.
Preparation[1]
A preparation method of tetraphenylporphine, including the following steps:
(1) In a 5m3 enamel polymerization reactor with mechanical stirring and jacket, and condensation reflux on the top of the tank, add 3.5m3 solvent propionic acid, then add 1025mol pyrrole and 1225mol o-methoxybenzaldehyde, and start from Blow N2 into the bottom of the polymerization reactor until the oxygen concentration in the gas phase at the outlet of the condenser at the top of the reactor is less than 3%. Then, introduce medium-pressure steam into the jacket of the polymerization reactor to heat the liquid in the reactor to reflux, and then reflux for 15 minutes. Stop heating and switch the medium-pressure steam in the jacket to circulating cooling water for cooling. When the liquid temperature in the polymerization reactor is about 90°C, stop flowing in circulating cooling water and switch to natural cooling. After the liquid temperature drops to normal temperature, the liquid in the polymerization reactor is transported to a bag filter and filtered to obtain a filtrate and a filter cake with a high moisture content. The filter cake is then further centrifuged to obtain 80.4kg of the filtrate and crude TPP filter cake. The filtrate obtained from the bag filter and centrifugal filter is pumped into a polymerization solvent distillation tower with a column volume of 5m3 and a 3-section DN400*1000 column section for rectification, dehydration and recovery to obtain the solvent propionic acid and unreacted pyrrole. , collect the recovered propionic acid and pyrrole for recycling back to the polymerization reactor for further use, and the residue from the distillation tower still will be discharged from the system and processed separately;
(2) Add 80.4kg of crude TPP filter cake obtained by centrifugal filtration into a 5m3 enamel oxidation reactor equipped with mechanical stirring and jacket, condensation reflux at the top, and gas distributor at the bottom, and add 3500kg into the kettle at the same time propionic acid, and then introduce medium-pressure steam into the reactor jacket to heat the liquid in the oxidation reactor. When the liquid in the oxidation reactor is heated to reflux, air is introduced to perform the oxidation reaction. The oxidation reaction time is 22 minutes. After the reaction is completed, the medium-pressure steam in the jacket of the oxidation reactor is switched to circulating cooling water for cooling. When the temperature of the liquid in the reactor is about 90°C, the circulating cooling water is stopped and replaced by natural cooling. When the oxidation After the temperature of the liquid in the reactor drops to normal temperature, the liquid in the oxidation reactor is transported to the bag filter for filtration, and then the filter cake obtained in the bag filter is subjected to centrifugal filtration. The filtrate obtained from the bag filter and centrifugal filter Directly circulate back to the oxidation reactor for continued use or pump into the oxidation reaction solvent distillation tower with a column volume of 5m3 and 3 sections of DN400*1000 for rectification, dehydration and recovery to obtain the solvent propionic acid, and collect the recovered propionic acid. In order to be recycled back to the oxidation reactor for further use, the residue from the distillation tower is discharged from the system;
(3) Wash the solid obtained by the centrifugal filter repeatedly with hot water and then centrifuge filter until the waste water obtained by centrifugal filtration is basically colorless. Then wash the solid obtained by centrifugal filtration with methanol and centrifuge again until the wastewater is colorless. The wastewater obtained by centrifugal filtration is basically colorless, and the solid washed with methanol is the product TPP. After vacuum drying at 80°C, 77.1kg of tetraphenylporphine product is obtained.
Main reference materials
[1] CN201210444418.2 A preparation method of tetraphenylporphine
[2] CN201610025485.9 A continuous preparation method of μ-oxotetraphenyl bimetalloporphyrin
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