Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-06-13
2001-12-04
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06326522
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for production of a specific bisphenol compound, that is, 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene.
DESCRIPTION OF PRIOR ART
1,3-Di(2-p-hydroxyphenyl-2-propyl)benzene is a kind of bisphenol compounds and is expressed by the structural formula (1):
As described in U.S. Pat. No. 3,393,244, this compound is already known and is useful as a raw material for the production of thermoplastic polymers such as polycarbonates, polyesters or polysulfones, surface active agents, or stabilizers.
In general, 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene is obtained by the reaction of 1,3-di(2-hydroxy-2-propyl)benzene having the formula (II)
with an execess amount of phenol in the presence of an acid catalyst.
According to above-mentioned U.S. patent, the desired 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene is obtained as follows. Phenol in an amount of 8-13 times in mols the amount of the compound (II) is placed in a reaction vessel and heated, and then hydrogen chloride gas is blown into the phenol so that the phenol is saturated therewith. Then, 1,3-di(2-hydroxy-2-propyl)benzene is added successively to the phenol at a temperature of 40-100° C., preferably at a temperature of 40-70° C. After the reaction, a large quantity of hot water is added to the resulting reaction mixture so that the desired reaction product is crystallized out of the resultant solution and filtered off.
On the other hand, according to Japanese Patent Laid-open No. 58-13528, the desired 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene is obtained as follows. 1,3-Di(2-hydroxy-2-propyl)benzene, phenol in an amount of 2-10 times in mols the compound and a solvent (for example, benzene) are placed together with concentrated hydrochloric acid in a reaction vessel. The mixture is then allowed to react at a temperature in the range of −20° C. and 100° C. (for example, at a temperature of 5° C.). After the reaction, the resulting oil layer is separated from the reaction mixture and neutralized with an aqueous alkaline solution. The oil layer is washed with hot water to remove unreacted phenol therefrom, followed by cooling the layer to crystalize the desired compound (I).
However, according to the process of the U.S. patent, phenol is used in a high molar ratio to 1,3-di(2-hydroxy-2-propyl)benzene so that the process has problems that the volume efficiency of reaction vessel used is low and hence the process is poor in productivity when it is employed for industrial production of 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene. Also according to the process of Japanese Patent Laid-open No. 58-13528, the process provides not a small amount of isomers or more highly condensed compounds such as five nuclear compounds. Accordingly, the known processes failed to produce the desired product, 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene, in high selectivity.
The present inventors have made intensive investigation to solve such problems as involved in the known processes and found that when phenol is reacted with 1,3-di(2-hydroxy-2-propyl)benzene in a reduced molar ratio of phenol in the range of 4-6 to 1,3-di(2-hydroxy-2-propyl)benzene at a relatively low temperature in the presence of an acid catalyst, adducts are formed of phenol and the resulting 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene and are crystallized out of the reaction mixture so that the reaction is thereafter allowed to proceed in a slurry, thereby suppressing the undesired by-production of isomers or highly condensed products such as five nuclear products and providing the desired 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene in high selectivity and high yield.
Therefore, it is an object of the invention to provide a process for production of 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene in high selectivity and high yield with reduced by-production of isomers or highly condensed products such as five nuclear products.
SUMMARY OF THE INVENTION
The invention provides a process for production of 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene which comprises:
reacting 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene with phenol in an amount of 4-6 times in mols the amount of the 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene in the presence of an acid catalyst at a temperature of 10-55° C. thereby crystallizing adducts formed of phenol and the resulting 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene out of the reaction mixture so that the reaction is effected in a slurry, and then
recovering 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene from the adduct.
DESCRIPTION OF PREFERRED EMBODIMENTS
According to the process of the invention, 1,3-di(2-hydroxy-2-propyl)benzene is reacted with phenol in an amount of 4-6 times in mols, preferably in an amount of 5.0-5.5 times in mols, the amount of 1,3-di(2-hydroxy-2-propyl)benzene, in the presence of an acid catalyst at a temperature of 10-55° C., preferably at a temperature of 20-50° C., more preferably at a temperature of 30-50° C., thereby crystallizing adducts formed of phenol and 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene out of the reaction mixture so that the reaction is effected in a slurry, and then the adduct is treated to recover the desired 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene.
In a preferred embodiment of the invention, phenol is placed in a reaction vessel, and hydrogen chloride gas is blown thereinto to saturate the phenol therewith, or concentrated hydrochloric acid (having a concentration of not less than 35% by weight) is added to phenol and then hydrogen chloride gas is blown thereinto to saturate the phenol therewith. Thereafter, 1,3-di(2-hydroxy-2-propyl)benzene and if necessary phenol are added successively to the phenol in the reaction vessel with stirring, and after the addition of 1,3-di(2-hydroxy-2-propyl)benzene, the mixture is further stirred to effect a post-reaction.
When 1,3-di(2-hydroxy-2-propyl)benzene is added to the phenol in the reaction vessel as mentioned above, it is preferred that a portion (preferably 50-80 mol %) of phenol to be reacted with 1,3-di(2-hydroxy-2-propyl)benzene is in advance separated and a mixture is prepared by mixing the portion with 1,3-di(2-hydroxy-2-propyl)benzene in the form of solution or slurry, and the mixture is added successively to the rest of the phenol placed in the reaction vessel.
According to the process of the invention, while 1,3-di(2-hydroxy-2-propyl)benzene (and phenol) is added successively to the phenol in the reaction vessel or while the post-reaction is carried out after the addition of 1,3-di(2-hydroxy-2-propyl)benzene, adducts are formed of phenol and 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene formed in the reaction and the adducts are crystallized out of the reaction mixture so that the reaction mixture becomes a slurry, so that, thereafter, the reaction is allowed to proceed in a slurry.
Thus, according to the invention, the desired reaction product or 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene is crystallized or deposited as adducts with phenol out of the reaction mixture and after the adducts are once crystallized, the reaction is carried out in a slurry. It is believed that, because the reaction is effected in a slurry as mentioned above, undesirable side reactions such as isomerization or higher condensation of the desired product to form five nuclear products is suppressed and the reaction yield improves.
As clear from the foregoing, the use of hydrocarbon solvents such as toluene or benzene in which 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene is soluble should be avoided in the process of the invention.
In the meantime, an effective amount of seed crystals (or crystallization nucleating agents) to promote the crystallization of the adduct, such as preferably 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene or its adducts with phenol, may be in advance added to the reaction mixture, or they may be added to the reaction mixture when 1,3-di(2-hydroxy-2-propyl)benzene is added to phenol. The amount of the seed crystals is not specifically limited, but it is usually in the range of 0.1-10% by weight in relation to the amount of phenol used.
In
Ekawa Kenji
Kumaki Kiyoshi
Nakaguchi Toru
Tsujigami Takafumi
Tsujimoto Kenzo
Honshu Chemical Industry Co. Ltd.
Merchant & Gould P.C.
Shippen Michael L.
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