JPH0331183B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for separating and recovering a brominated acenaphthylene condensate as a powder from a solution obtained in its manufacturing process. Brominated acenaphthylene condensate (hereinafter referred to as Con-
BACN) is a compound with excellent flame retardancy and radiation resistance, and has the property of making the resin flame retardant and radiation resistant when blended with various flammable resins. In addition, since it has a double bond in its molecule, it can be grafted onto resins by subjecting it to free radical generation treatment, and since it is a condensate, it has excellent compatibility with resins, so it can last for a long time. It has been attracting attention as a compound that can maintain stable flame retardancy and radiation resistance when used as a compound (Japanese Unexamined Patent Publication No. 122862/1983). The purpose of the present invention is to provide a method for separating and recovering the body. Con-BACN as used in the present invention is a compound containing at least one bromine in an aromatic ring, and brominated acenaphthene is formally condensed through a Friedel-Crafts reaction to form a multimer with a degree of condensation of 2 or more. Con-BACN is then converted into Con-BACN through a dehydrobromination reaction. That is, the general formula [] or [] (In the formula, n and n' represent integers from 1 to 5)
It is a condensation product whose constituent elements are units represented by, and the condensation mode is an intermolecular bond between the benzylic carbon of acenaphthylene and the aryl carbon of acenaphthylene. The connection points are, for example, 1 (or 2), 5'-

[Formula] or 1 (or 2), 6'-

[Formula] etc. are exemplified, but there are also 1 (or 2), 3'-, 1 (or 2), 4'-, 1 (or 2), 7'-, 1 (or 2), 8 ′- and other combinations are possible. Those with a degree of condensation of 3 or more have the number of constituent units increased by any of these bonds. The condensate referred to in the present invention preferably has a degree of condensation of 10 or less, which has excellent compatibility with the resin. Con-BACN is generally acenaphthene bromination,
Produced by condensation and dehydrobromation reactions. That is, acenaphthene is brominated and condensed in a halogenated hydrocarbon solvent in the presence of a Lewis acid catalyst by adding bromine, and the resulting halogenated acenaphthene condensate is dehydrobrominated with a base such as caustic potash-methanol. Manufactured by a reaction. The dehydrobromination reaction is carried out in a base-inert solvent such as caustic potash-methanol, ie, a halogenated hydrocarbon or aromatic hydrocarbon solvent. Con−BACN obtained by these manufacturing processes
As a method for separating and recovering Con-BACN from a solution,
(1) A method of evaporating the solvent from the Con-BACN solution and (2) A method of adding the Con-BACN solution to a poor solvent and separating it by precipitation can be considered, but method (1)
Con-BACN is hard to handle because it solidifies into a resin and cannot be obtained as a powder. In addition, although this resin-like Con-BACN can be used for practical purposes as it is, Con-BACN
A small amount of solvent remains inside and is relatively difficult to remove. Therefore, the melting point of the obtained Con-BACN is 50°C to 80°C, which is 50°C to 70°C lower than that of the powder, and when the compound is kneaded with resin on a roll, it may cause roll adhesion or solvent It has the disadvantage of poor workability, such as corrosion of processing and molding machines due to thermal decomposition. Therefore, the solvent in Con-BACN is removed and Con-
If BACN could be made into a powder with a higher melting point, it would be extremely advantageous in handling and roll kneading operations. In method (2), a method is known in which a solution of Con-BACN is added to acetone, which is a poor solvent, and then reprecipitated and recovered as a powder. (Y.Morita and
M.Hagiwara, J.Appl.Polym.Sci., 27 3329
(1982)) However, Con−BACN by this method
To recover Con-BACN, since Con-BACN dissolves in acetone to some extent, the Con-BACN solution obtained in the reaction was concentrated in advance, and then cooled acetone (0 to -
Since the method is to add the liquid to a liquid (10°C) and re-precipitate, it has the disadvantage of requiring complicated operations. Also Con
-The recovery rate of BACN also has the disadvantage of being low. The present inventors used a reprecipitation method using a poor solvent to recover Con-BACN as a powder, and with a simple operation, Con-BACN was recovered.
-As a result of searching for various types of poor solvents to increase the recovery rate of Con-BACN, we found that when using a saturated aliphatic monohydric alcohol with 3 to 5 carbon atoms, Con-BACN can be easily recovered with a high recovery rate. The present invention was completed by discovering that it can be taken up as a powder. That is, in the present invention, by adding a solution of Con-BACN obtained by bromination, condensation, and dehydrobromination of acenaphthene to a saturated aliphatic monohydric alcohol having 3 to 5 carbon atoms, Con- A method for separating and recovering Con-BACN, which is characterized by precipitating BACN as a powder, is provided as part of the process. Con-BACN obtained in the manufacturing process referred to in the present invention
The organic solvent of the solution refers to a good solvent that dissolves Con-BACN, and a halogenated hydrocarbon or aromatic hydrocarbon that is inactive in the dehydrobromation reaction is selected. Examples include carbon tetrachloride, chloroform, methylene chloride, ethylene dichloride, ethylene dibromide, chlorobenzene, benzene, toluene, xylene, and ethylbenzene.
Further, the concentration of the Con-BACN solution is not particularly limited, but usually 5 to 70% by weight is used. Saturated aliphatic monohydric alcohols having 3 to 5 carbon atoms used in the process of the present invention include 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-methyl-2 -propanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1
-butanol, 3-methyl-1-butanol, 2
-Methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl-1-propanol, etc. can be mentioned, but it is easy to dry the powder after reprecipitation and industrially available. 1-propanol, 2-propanol, 1-butanol, 2-butanol, or 2-methyl-2-propanol is practically preferred. For alcohols with less than 2 carbon atoms, Con−BACN
The dispersibility of Con-BACN is poor, making it impossible to precipitate Con-BACN as a solid, and in the case of alcohols with carbon atoms of 6 or more, the solubility of Con-BACN increases,
There is a drawback that the recovery rate of Con-BACN is low. In addition, in the case of polyhydric alcohols having a valence of two or more, the boiling point is generally high, and the resulting powder cannot be easily dried. The amount of these saturated aliphatic monohydric alcohols used is
1 by volume for the Con-BACN solution normally added
~20 times the amount is used, preferably 2 to 10 times the amount. If the amount of alcohol is less than the same amount as the Con-BACN solution, there is a drawback that the recovery rate of Con-BACN is low, and if the amount is more than 20 times, there is no problem with reprecipitation itself, but it is not preferred because it is not economical. . Con−
Reprecipitation of BACN is carried out by adding a Con-BACN solution to the alcohol, and it is preferable that stirring is performed at that time. In addition, during normal stirring, etc., Con-BACN partially solidifies, and after drying the crystals,
Since it may be necessary to crush the mixture, it is more preferable to perform stirring with shear force. The term "agitation with shearing force" here refers to, for example, forced agitation using a two-screw kneading machine or agitation with shear such as a homomixer.
It is possible to promote the dispersion of precipitation by forced stirring of the good solution and the poor solvent, and to enable the good solvent to come into contact with the poor solvent in a dispersed manner, resulting in efficient precipitation. In other words, in the case of a normal reactor with one stirring mechanism, dispersion is inefficient and crystal precipitation is slow;
For example, if two stirrers are used to improve dispersion, the contact surface between the good solvent and the poor solvent will be expanded, so the Con-
The good solvent remaining in BACN is extracted, the precipitation of the target product is promoted, and efficient precipitation of Con-BACN becomes possible. Furthermore, since the obtained crystals are obtained as fine powder, crushing after drying is not necessary. The temperature at which the Con-BACN solution is added to these alcohols is not particularly limited as long as it is below the melting point of Con-BACN, but usually room temperature is sufficient. The precipitated Con-BACN powder can be separated by a conventional method. For example, it can be separated by centrifugation, suction, spray drying, etc. As is clear from the above, by carrying out the method of the present invention, Con-BACN solution obtained from the manufacturing process can be easily converted into Con-BACN solution.
Since BACN can be separated as a powder with an extremely high recovery rate, an economical method for producing Con-BACN has become possible. In addition, Con-BACN obtained by the present invention is obtained as a fine powder and as a compound with a higher melting point than Con-BACN made into a resin, so it is easy to handle and roll workability during roll kneading with resin. is also excellent. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. Example 1 308 g of acenaphthene and 24 g of ferric chloride were added to 2.8 g of carbon tetrachloride and kept at 30°C. A solution containing 1.9 kg of bromine and 0.5 kg of carbon tetrachloride was added dropwise to this solution over 5 hours. After the dropwise addition, the temperature was raised to 55°C and the reaction was carried out until the color of bromine disappeared. After removing insoluble matter in the reaction solution and washing the reaction solution thoroughly with water, 144 g of potassium hydroxide was added to 0.6 g of methanol while heating under reflux.
A solution dissolved in was added dropwise over 1 hour, and the reaction was continued for another 1 hour. After cooling the reaction solution, potassium bromide salt was removed by filtration, methanol was distilled off, and water was washed three times to obtain a carbon tetrachloride solution containing 620 g of Con-BACN.
I got it. As a result of the analysis, the obtained Con−BACN
has a bromine content of 67%, and the degree of condensation measured by gel vermi-ation chromatography is less than 35% monomer.
%, dimer 42%, trimer-octamer 23%. With this Con-BACN carbon tetrachloride solution, Con
-0.45 containing 77.5g of BACN was used for the next reprecipitation. The above Con-BACN carbon tetrachloride solution was added at room temperature to 1.8 g of i-propanol being vigorously stirred with a Labo Disparza (manufactured by Mitamura Riken Kogyo Co., Ltd.).
It was dripped in 20 minutes. Precipitation of fine powder occurred simultaneously with the dropping. After dropping, stirring was continued for another 20 minutes to completely precipitate the powder, which was then separated and dried at a temperature of 75°C to obtain a reddish brown powdered Con- with a melting point of 125-145°C.
70.5 g of BACN was obtained. Con−BACN From carbon tetrachloride solution to Con−BACN
The recovery rate corresponds to 91%. Example 2 0.45% of the carbon tetrachloride solution containing 77.5g of Con-BACN produced in Example 1 was added to 1.8% of n-propanol while vigorously stirring with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at room temperature. It was dripped in 30 minutes. Precipitation of fine powder occurred simultaneously with the dropping. After dropping, continue stirring for another 20 minutes, separate and dry to determine the melting point.
68.3g of reddish brown powdered Con-BACN at 124-146℃
I got it. Con−BACN From carbon tetrachloride solution to Con−BACN
This corresponds to a recovery rate of 88.1%. Example 3 While vigorously stirring 1.8 tert-butanol in a lab disperser, add the tert-butanol prepared in Example 1.
Carbon tetrachloride solution containing 77.5g Con-BACN
0.45 was added dropwise at room temperature over 20 minutes. Precipitation of fine powder occurred simultaneously with the dropping. After the addition, stirring was continued for another 20 minutes, and the mixture was separated and dried to obtain 70.1 g of Con-BACN in the form of a reddish brown powder with a melting point of 124 to 145°C. Con−BACN From carbon tetrachloride solution to Con−BACN
The recovery rate is equivalent to 90.5%. Example 4 77 g of acenaphthene and 6 g of ferric chloride were added to 700 ml of carbon tetrachloride and kept at 30°C. A solution of 475 g of bromine and 125 ml of carbon tetrachloride was added dropwise to this solution over 4 hours. After the dropwise addition, the temperature was raised to 55°C and the reaction was carried out until the color of bromine disappeared. Insoluble matter in the reaction solution was removed by filtration, the reaction solution was thoroughly washed with water, concentrated to dryness, the residue was dissolved in 550 ml of benzene, and a solution of 36 g of potassium hydroxide dissolved in 150 ml of methanol was dissolved under heating under reflux. The mixture was added dropwise over a period of time, and the reaction was further continued for 1 hour. After cooling the reaction solution, potassium bromide salt was removed by filtration, methanol was distilled off, and the solution was washed with water three times.
600 ml of a benzene solution containing 152 g of Con-BACN was obtained. The obtained Con-BACN had a bromine content of 68%, and the degree of condensation measured by gel permeation chromatography was 36% for simple substance or less, 43% for 2 simple substance, and 3 to 8.
It was 21% on a non-consolidated basis. This benzene solution was added dropwise over 30 minutes at room temperature into 2.4 g of n-amyl alcohol, which was being slowly stirred with an ordinary blade. After dropping, precipitation of powder occurred. After the addition, stirring was continued for another 30 minutes, and the powder was separated and dried. Although some solidified Con-BACN was contained in the powder, it could be easily crushed with a household mixer, and the melting point was 126. ~146℃ yellowish brown powder
130.7 g of Con-BACN was obtained. Con−BACN from benzene solution of Con−BACN
The recovery rate is equivalent to 86%. Comparative Example A carbon tetrachloride solution (0.45 g) containing 77.5 g of Con-BACN produced in Example 1 was added to cold acetone (0 to
-10°C) 1.8 while stirring in the same manner as in Example 1. After dropping, the precipitated powder was separated and dried to give a yellowish brown powdered Con- with a melting point of 126-146℃.
55.0 g of BACN was obtained. The recovery rate of Con-BACN from the Con-BACN carbon tetrachloride solution corresponds to 71%.

Claims (1)

[Claims] 1 In a method for separating and recovering a brominated acenaphthylene condensate produced by bromination, condensation, and dehydrobromination reaction of acenaphthene, a solution of the obtained brominated acenaphthylene condensate is treated with a saturated aliphatic compound having 3 to 5 carbon atoms. A method for separating and recovering a brominated acenaphthylene condensate, the method comprising adding the condensate to a hydric alcohol.