SU1728228A1 - Method of 9,9-bis-(4-aminophenyl)-fluorene synthesis - Google Patents

Abstract

The invention relates to substituted fluoroene, in particular the preparation of 9,9-bis- (4-aminophenyl) -fluorene intermediate for the synthesis of polyamides. The goal is to simplify the process. It is reacted with 9,9-dichloro-fluorene with aniline and aniline hydrochloride, molar ratio 1: (2.5-3.5) :( 1.5-2.2), at 150-155 ° C, followed by neutralization the reaction mixture with an aqueous solution of ammonium hydroxide, distilling off aniline (excess), purification in hydrochloric acid, and recrystallization. These conditions simplify the process by reducing its duration by 4-5 times, the consumption of reagents (1.1-2.4 times) and the energy for heating, the reaction mass. 1 tab. iin C

Description

The invention relates to a process for the preparation of 9,9-bis- (4-aminophenyl) -fluoren (anilinefluorene), which is used as an intermediate product in the synthesis of film- and fiber-forming polyimides possessing high heat and heat resistance, as well as dyes .

A known method for the preparation of aniline fluorouren by condensation of fluorenon-9 with aniline hydrochloride in aniline medium at the boiling point of the reaction mixture at a molar ratio of reagents of 1: 4: 11. The yield of the target product is 54% 1.

The disadvantage of the method is the use of a large excess of aniline, which reduces the selectivity of the process and the quality of the final product, which needs additional purification from solvents (benzene). The use of large quantities of aqueous alkaline solutions and organic solvents at the isolation and purification stage leads to the formation of significant volumes of wastewater.

A known method for the preparation of aniline fluorouren in the interaction of fluorenone-9 with aniline hydrochloride at 220 ° C at a moxi

YU

with

Yu GO 00

The relative ratio of reagents is 1: 2. From the obtained alloy, anilinfluoroene hydrochloride is washed out by repeated treatment with hot water in large volumes (10 liters of water per 170 g of product). The resulting pro duction is purified by recrystallization from chlorobenzene in a mass ratio of 1:15. The output of aniline fluoroene 52-57% 2.

The disadvantage of the method is its impossibility to use it in industrial conditions due to difficulties in hardware design: when extracting anilinefluorene hydrochloride from the melt with water, the frozen resin is difficult to dissolve, cannot be mixed, which leads to equipment breakdown and requires significant amounts of water. The latter is associated with the formation of large quantities of aniline-containing wastewater and also prevents the use of the method on an industrial scale.

A known method of producing anilinefluorene by reacting fluorenone-9 with hydrochloric acid analyte in aniline medium at a molar ratio of reagents of 1: 2.7: 10.4 at 175 ° for 3 hours.

The selection of the target product from the reaction mass includes the distillation of aniline, filtration of the bottoms residue, purification re-solution of the technical product in hydrochloric acid and subsequent recrystallization of the resulting aniline fluoroene from chlorobenzene. The yield of the target product with so pl. 236-237 ° С40% 3.

The disadvantage of this method is the use of a large excess of aniline. This reduces the selectivity of the process and necessitates the repeated and complex purification of a technical product, which leads to a decrease in its yield and the formation of significant amounts of aniline-containing wastewater. In addition, fairly difficult-to-use fluorenone-9 is used as the main raw material.

The closest to the present invention is a method for the preparation of anilinefluorene by the interaction of fluorenone-9 with aniline and aniline hydrochloride at a molar ratio of reagents 1: (4-6): 2.4 at 160-165 ° C.

The disadvantages of this method are the use of fairly difficult-to-use fluorenone-9, the duration of the arylation stage (up to 5 hours), the use of an increased excess of aniline.

The aim of the invention is to simplify the process.

This goal is achieved by the method of obtaining 9,9-bis- (4-aminophenyl) -fluorene by condensation of 9,9-dichlorofluorene with aniline hydrochloric acid in aniline medium at a molar ratio of reagents of 1: (1.5-2.2): (2.5-3.5) respectively, with

150-155 ° C, followed by neutralization of the reaction mixture with an aqueous solution of ammonium hydroxide, distillation of excess aniline, purification in hydrochloric acid and recrystallization from chlorobenzene.

Example 1. A round-bottom flask equipped with a stirrer and reflux condenser is charged with 98.0 g (1.05 mol) of freshly distilled aniline having a so-called boiling point. 184 ° С, it is heated to 60 ° С, a shalk is turned on and 70.5 g of 9.9-dichlorofluorene 99.8% are loaded by content of the basic substance (70.36 g in terms of 100%, 0.3 mol ), the mixture is heated to 100 ° C, while 9.9-dichlorofluorene is completely dissolved in aniline, after which, at 100-102 ° C, 77.6 g (0.6 mol) of aniline hydrochloride is added. Then the reaction mixture is heated to 150 ° C and maintained at this temperature for 1 h. At the end of the reaction, the mixture is cooled

5 to 80 ° C and 185 ml of a 25% ammonium hydroxide solution are introduced into the flask. This is necessary to neutralize hydrochloric acid in the reaction mass (that formed as a result of the condensation reaction, as well as

0 of that introduced into the reaction mass in the composition of aniline hydrochloride in order to more completely remove aniline by steam distillation. The reflux condenser is then replaced directly and the excess

5 aniline direct steam. The volume of azeotropic shoulder strap at the end of distillation is 542.3 ml, the content of aniline in it is 18%. Using a separatory funnel, 82.8 ml (84.6 g) of aniline was separated, which after distillation was again

0 used in the condensation process.

VAT residue containing light gray precipitate of aniline-fluorene, cooled to 25 ° C and filtered. The anilinefluorene precipitate on the filter is washed with distilled water, dried at 60-70 ° C and sent for purification. The mother liquor in the amount of 256.4 g, obtained after filtration of anilinefluorene and containing 25% ammonium chloride, is directed to the isolation of chloride

0 ammonium.

For the purpose of purification, the aniline fluoride obtained is dissolved at the boil in a 1% hydrochloric acid solution (40 g of hydrochloric acid solution per 1 g of product),

5, 1 g of activated carbon is added, boiled for 20 minutes and the activated carbon is filtered off. Aniline fluoro is precipitated in the filtrate by adding aqueous ammonia or sodium hydroxide solution to a pH of 8–9. Fallen white precipitate of the target product

filtered off, washed with water, dried at 100 ° C. 80.9 g of purified anilinefluorene are obtained, which is 77.6% of the amount theoretically calculated for 9.9-dichlorofluorene.

After recrystallization from chlorobenzene or o-xylene, 80.2 g (76.9% of theory) of 9,9-bis- (4-aminophenyl) -fluorest.pl. 236-237 ° C.

Examples 2-12. The process is carried out under the conditions of Example 1. The specific process parameters and its results are presented in Table 1.

The technical and economic efficiency of the proposed method consists in simplifying the process, which is expressed in using the more available 9.9-dichlorfluorene, reducing the duration of the arylation stage (4-5 times), reducing the consumption of aniline (1.1-2.4 times

for) and reducing energy consumption for heating the reaction mass.

Claims (1)

Claims 1. A method for producing 9,9-bis- (4-aminophenyl) -fluorene by reacting 9-substituted fluorene with aniline and aniline hydrochloride at elevated temperature, comprising the step of distilling off excess aniline, followed by purification of the product in hydrochloric acid and recrystallization characterized in that, in order to simplify the process, 9,9-dichlorofluorene is used as 9-substituted fluorene, which is reacted with aniline and aniline hydrochloride at their molar ratio of 1: 2.5-3.5: 1 , 5-2.2, respectively, temperatures e 150-155 ° C, followed by neutralization of the reaction mixture with an aqueous solution of ammonium hydroxide.