DE2061531A1 - Process for the preparation of high purity 2,2 di (4 hydroxyphenyl) propane - Google Patents

Description

SHELL INTERNATIONAL RESEARCH MAATSCHAPPIJ N.V., The Hague, Netherlands

¹¹ process for the 'production of high-purity 2,2-di «- (4-hydroxyphenyl) propane"

Priority: December 15, 1969, V.St.A., No. 885 333 December 15, 1969, V.St.A., No. 885 334

The invention relates to a method for the production of high purity 2,2-di (4-hydroxyphenyl) propane.

2,2-Di (4-hydroxyphenyl) propane made by conventional methods contains low proportions, e.g. of up to about 5 percent by weight, of difficult-to-separate by-products. A corresponding product with such a degree of purity is indeed suitable in many cases for the production of various Products such as epoxy resins or surface coatings based on such resins. For some uses, for which have recently become known as for the production

10 9 8 2 6/1933

ORIGINAL

206 j.531

certain high molecular weight, linear polymers, but becomes highly pure, i.e., 2,2-di (4-hydroxyphenyl) propane containing less than 0.5 weight percent impurities needed. In the manufacture of polyaryl carbonate resins, impurities levels of about 0.3 percent by weight are allowed be present. For the production of first quality resins, uncolored, i.e. completely white 2,2-di- (4-hydroxyphenyl) -propane is also used needed.

The previously proposed cleaning methods for the aforementioned Compounds are either unsuitable or not sufficiently economical for large-scale operations. By distillation In general, impurities with relatively low volatility cannot be separated off. The crystallization out conventional organic solvents, such as chlorobenzene, can be satisfactory in terms of removing impurities, on the other hand, however, lower the yield of the purified product. Cleaning processes in which the product recrystallizes from large amounts of water or washed with these or in another Wise treated are economically viable by the requirement of the separation of phenolic components of the diluted solution or the treatment of the water before its disposal to avoid the wastewater contamination impaired.

The object of the invention was to find a new, economical process for the production of high-purity, excellently white colored 2,2-di- (4-hydroxyphenyl) -propane available.

109826/1933

This object is achieved by the invention.

The invention thus relates to a method for production

/ Highly pure 2,2-di ~ (4-hydroxyphenyl) propane, which is characterized in that a single-phase, liquid mixture of 2,2-di (4-hydroxyphenyl) propane, phenol and 3 "to 48 percent by weight , based on the phenol, water is heated from an initial temperature of 32 ^° C. to a temperature at which an adduct of equimolar proportions of 2,2-di- (4-hydroxyphenyl) propane and phenol crystallizes out, the crystals obtained ( separates from the mother liquor and, optionally after washing with a non-solvent for the 2,2-di- (4-hydroxyphenyl) propane, separates the phenol component from the crystals.

In the process of the invention, the phenol / 2,2-di- (4-hydroxyphenyl) propane weight ratio is preferably 0.9: 1 to 10: 1, in particular 1.2: 1 to 8: 1, especially 1.4: 1 to 5 s1

According to the invention, the single-phase, liquid mixture preferably contains 10 to 46 percent by weight, based on the phenol, of water.

The starting temperature of the single-phase, liquid mixture in the process of the invention is preferably in a range from 32 to 77 ^° C., in particular from 38 to 77 ^° C.

According to the invention, the single-phase liquid mixture can be cooled in a conventional manner. ^{The mixture is preferably cooled to temperatures of 10 to 55 °} C., in particular with stirring, in the course of which large crystals of excellent purity are obtained

109826/1933

receives. If in the process according to the invention the crystallization

occurs discontinuously, cooling rates of 1 to 10 ° C./h are suitable, although lower or higher cooling rates can also be effective. If the crystallization takes place continuously, residence times of the crystals in the crystallization medium of 0.5 to 10 hours are suitable, with residence times of 1 to 3 hours being preferred. The crystals can be separated from the mother liquor by conventional methods such as decanting, filtering or centrifuging. Jt was surprisingly found that the above!

Crystals formed by the medium have a high resistance to- ^;

Impact
mechanical / , which causes the formation of relatively large crystals and therefore facilitates the separation from the mother liquor, the crystals crumbling at most to a small extent.

According to the invention, the mother liquor is advantageously freed from water by known drying processes, for example by extraction with solvents in which water is preferably soluble, and the mother liquor freed from the water is wholly or partially recycled to purify further portions of 2,2-di- (4-hydroxyphenyl) ~ propane. The water is preferred by the mother liquor separated by a simple distillation,

and it is added, at least in part, to a fresh amount of the single-phase liquid mixture for replenishment purposes.

i If necessary, the separated crystals are marked with a non- '

Washed solvent for the 2,2-di- (4-hydroxyphenyl) propane. ■

109826/1933

suitable

Examples of corresponding / non-solvents are hydroxy aromatic hydrocarbons, such as phenol, chloroalkanes,

chlorinated aromatic or aliphatic / aromatic hydrocarbons, such as ethylene dichloride, and / However, it has been found that such washing is generally necessary to achieve the desired high degree of purity is not absolutely necessary. However, if you want to do a wash, you can for this it is advisable to use phenol, in particular in the form of an aqueous mixture. In either case, the phenol becomes final separated from the crystals. Any known methods can be used, for example extraction with a solvent in which the phenol is preferred is dissolved, or a distillation. In the latter case should the crystals be heated, what is necessary or if necessary is carried out at reduced pressure. When the crystals are freed from the phenol, the temperature is left while heating preferably not to exceed a value of 205 ° C. in order to prevent thermally induced dissociation or a corresponding degradation of the product.

The process of the invention can be discontinuous, continuous or carried out semi-continuously. The single-phase, liquid mixture can be produced by combining the individual components can be made in any order. However, it is advisable to use the impure 2> 2-di- (4-hydroxyphenyl) propane add the phenol premixed with water and use elevated temperatures, preferably temperatures which the single-phase, liquid mixture, as mentioned, must have before cooling. Instead of impure 2,2-di- (4-hydroxy-

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BAD ORIGJNAL

phenyl) propane can also add to the phenol premixed with water equimolar proportion of the adduct of 2,2-di- (4-hydroxyphenyl) propane and phenol are added when the aforementioned adduct has a lower degree of purity, so that it can be after the phenol separation an insufficiently pure 2,2-di- (4-hydroxyphenyl) propane would provide .. In particular, such an impure adduct can be obtained from a reaction mixture which is produced by condensation obtained from phenol with acetone and unconverted Contains phenol. The aforementioned reaction mixture is used to "separate water / water, unreacted acetone and gaseous." Subjected impurities to distillation, after which the residue obtained is cooled to temperatures at which the aforementioned adduct crystallizes out. The resulting crystals are finally separated from the mother liquor.

A condensation reaction of phenol with acetone as mentioned above can be carried out by a continuous method. In general, temperatures are h of about 20 applied to about 85 C, it is carried out in the presence of an acid catalyst such as hydrogen chloride, hydrogen bromide, or boron trifluoride, and there is a molar excess of phenol, based on the acetone used. For example, a phenol / acetone molar ratio of 3: 1 to 25J1 is used. applied. The reaction can be accelerated by adding sulfur compounds known for their promoter effect, such as sulfonyl chloride, hydrogen sulfide, methyl mercaptan or butyl mercaptan. The reaction mixture can be drawn off continuously and together with to remove the water of reaction

109826/1933

! '"I'lsp ν'! · :: r"! '!! nin; !!!! nin |! Ii || ii: u'! -! Ii! :: '·: "- ■ -" ^ ■ -. IMH-H- r. ■ »■■

optionally present unconverted acetone and volatile impurities (including catalyst and / or _r Pro motor when they are volatile) are distilled. The catalyst

in a known manner sator and / or promoter can (can) with advantage / dried and be returned to the reaction zone. The weight ratio nis of the unreacted phenol to that in the dried reaction mixture The desired product contained can vary greatly depending on the respective process conditions be. However, it is expedient to use a value νοη.0,9ί1 up to 10: 1, preferably 1 2: 1 to 8: 1. Such weight ratios can inevitably by using an excess of phenol, based on the acetone, by partial separation of the excess, unreacted phenol, for example by fractionation, or by adding further phenol After heating during the drying stage, the reaction mixture is brought to temperatures cooled from about 45 Ms to about 70 C, with a solid, crystalline material and a mother liquor containing phenol and impurities can be obtained. This first stage of crystallization is preferably in a substantially anhydrous

H ₂ O

- Medium, i.e. one containing less than about 0.1% by weight Medium. The crystalline material can be separated using conventional separation techniques, for example by decanting, filtering or centrifuging. The mother liquor can expediently wholly or partly for the purpose of conversion be returned to further product in the reaction zone. If in the process of the invention a discontinuous one Crystallization is used, the separated crystal

109826/1933

le'mit mixed with phenol and water, being a single-phase, liquid Mixture is obtained from which the purified adduct crystals are to be obtained. The phenol and the water can either in separate form or together as a water / phenol mixture.

A particular advantage of the process according to the invention is based on the fact that all types of impurities are separated off. Examples of these impurities are different amounts of the 2,4'-dihydroxy isomer, of trisphenols and certain intramolecular ones Condensation products with a functional group such as p- (2,2,4-trimethyl-4-chromanyl) phenol and his Isomers, as well as coloring impurities with an indefinite structure. Through the 2,4'-dihydroxy isomers as well as through the intramolecular It is known that condensation products break the polymer symmetry and the formation of products with high Molecular weight prevented. On the other hand "can trisphenols, which are, for example, by condensation of 2 mol Forming acetone with 3 moles of phenol changes the final properties of the polymer by causing branching or branching even cause gelation through crosslinking.

Since, as can be seen from the examples, all impurities, i.e. both high melting point impurities such as tris-

about ₀

phenol (Pp. = / 195 C), and low-melting impurities such as 2- (2-Hydroxypheny1) -2- (4-hydroxyphenyl) propane (Pp. 11O = ⁰ G), as well as coloring impurities by the process of the invention are removed as far as possible, the conventional

109826/1933

Freezing point used as a measure of product purity is no longer a satisfactory criterion. However, it is known that the determination of the "APHA color number" (platinum / cobalt color standard) in alkaline aqueous solution a more stringent read for coloring impurities in 2,2-di- (4-hydroxyphenyl) -propane to disposal. A particular advantage of the process according to the invention is that it is a product with a basic one Provides color number less than 60 APHA units.

The examples illustrate the invention.

example 1

23 parts by weight of 2,2-di- (4-hydroxyphenyl) propane (technical

. Weight - <f °

Quality; Commercial product) with a purity of 96 /, a basic APHA color number of 112 and a solidification point of 154 »6 ⁰ C in 77 parts by weight of phenol, which contains 10 percent by weight, bezogen'auf the phenol containing water, was added, and the resulting mixture is heated to about 57 ° C. In this case, a single-phase mixture which is allowed to cool over 8 hours with gentle stirring at 32 ⁰ C forms. Large crystals of an adduct formed from equimolar proportions of 2,2-di- (4-hydroxyphenyl) propane and phenol. This crime

by filtration

stalls become / in a Buchner funnel easily and without damage separated from the mother liquor, and then the filter cake is used to separate enclosed mother liquor pro Part by weight washed with 0.6 part by weight of phenol. The adduct crystals are then used to separate the phenolic coraponents heated about 20 torr to about 199 ° C, with purified

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BATH

2,2-di- (4-hydroxyphenyl) propane remains.

The aforementioned operation is repeated with another commercially available • 2,2-di (4-hydroxyphenyl) propane, technical quality, having that same degree of purity, a basic APHA Parbzahl of 207 and a solidifying point of 154.1 ⁰ C . 35 parts by weight of the aforementioned 2,2-di- (4-hydroxyphenyl) propane are introduced into 65 parts by weight of phenol, which is about 33 percent by weight, based on the phenol, distil ^. Contain lated water.

The aforementioned process is also carried out with the same 2,2-di- (4-hydroxyphenyl) propane technical quality as repeated on the first attempt. 37 parts by weight of this compound becomes 63 parts by weight Phenol added, which contain 40 percent by weight, based on the phenol, of distilled water.

For comparison purposes, the above procedure is carried out with a mixture of 29 parts by weight of 2,2-di- (4-hydroxyphenyl) propane, ™ Repeatedly 27 parts by weight of phenol and 44 parts by weight of water. Two separate liquid phases are formed, which does not correspond to the method according to the invention.

The results obtained in the aforementioned four experiments are

a .

can be seen from Table I. Table I also shows values relating to / 2,2-di- (4-hydroxyphenyl) propane, which were obtained from adduct crystals which were not subjected to any phenol washing prior to the heating for separating off the phenol. Such products can already be used for numerous practical purposes

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BATH ORIGINAL

relatively satisfactory results achieved. The fourth End product obtained in the experiment (not according to the invention) proves to be inferior in terms of purity and coloration.

Table I.

properties ]
I.
\ APHA color number,
jpmessen
a solution
of 50 g / 70 ml
Methanol Attempt 1 after
the
Phe
nol
Laundry Attempt 2 ι after
the
Phe-
nol-
! Laundry Attempt 3 after
the
Phe-
nol-
laundry !
Tries Basic
APHA color number ror
ler
'he-
/ ashes 18th before
the
Phe
nol
Laundry 45 before
the
Phe
nol—
Laundry 13th nacn
the
Phe- ■
nol-
} Laundry Gas chromato- ' 75 106 37 j
13th graphic - 92 72 Analysis, % By weight 0.06 -
■ 0.32 '0.09 2 - ^ - hydroxy
phenyl) ^ - (4-
hydroxypheny1) -
propane 0.35 0.03 1.43 ■
0.03 0.01 0.09 Isomers of p-
(2,2,4-trimester
ethyl-4-chroma-
myl) phenol 0.05 0.01 0.05 0.04 0.07 0.03 Trisphenol 0.07 99.9 0.30 99.6 - 99.83 0.02 2,2-Di- (4-hv-
droxyphenyl; -
propane
(Difference
determination) 99.5 98.2 99.86

The separation effect in the gas chromatographic analysis was determined by injecting the trimethylsilyl ether derivatives of the respective

109826/193 3

ligen sample in a column filled with a commercially available dimethyl bilicon rubber on glass beads and with
Determined quantitatively with the aid of a hydrogen flame detector.

The basic APHA color number was at temperatures from 25 to
3O ⁰ C to a solution of 7 _t 5 g 2,2-di- (4-hydroxyphenyl) propane in 50 ml of 1 sodium hydroxide solution η 10 minutes after preparation of these
• Solution determined.

Example 2

2,2-Di- (4-hydroxyphenyl) propane is after a continuous. chen working method produced in an autoclave by

about _o , _r .

Reacts phenol at / 55 C with acetone (molar ratio phenol / acetone 6: 1) in the presence of hydrogen chloride and methyl mercaptan. The reaction mixture obtained is by Deetillatlon from the water of reaction, unreacted acetone and
volatile impurities such as catalyst and promoter,
anechließend liberated and cooled to about 57 ⁰ C. Crystals of an adduct containing equimolar proportions of 2,2-di- (4-hydroxyphenyl) propane and unreacted phenol are formed. This adduct does not yet have the desired high degree of purity and is therefore subjected to purification according to the process of the invention. The adduct is accordingly mixed with so btaeeetnen amounts of phenol and erhltBtem Vaeeer that a single-phase, liquid "mixture is obtained at about 60 ⁰ C, which" about 34 percent by weight of 2,2-di '- (4-hydroxy | ihenyl) - propane, pro , 'part by weight aie "er Ver &indun" 1 * 5 weight part fhenol, eowli 35 percent by weight, based on the phenol "contains water"

1-09 8 26/19 33

BATH ORIGINAL

This mixture is • the cooled under gentle stirring for about 4 to about 24 ⁰ C STUN. Relatively large adduct crystals are formed, which are centrifuged off at 24 ° C. The crystals are about 0.35 part by weight per part by weight. aqueous phenol ether (about 10 weight percent, based on the phenol, _H? O). The crystals are then freed from phenol by heating them at about .1 Torr up to about 202 ^° C. The molten 2,2-di- (4-hydroxyphenyl) propane obtained as residue is cooled, whereupon it solidifies. The solid bond has the properties shown in Table II. For comparison purposes, Table II also shows the properties of the 2,2-di- (4-hydroxyphenyl) methane, which was obtained from the adduct which was isolated first and which was not treated according to the invention.

Table II

properties from the
first adduct from the
End adduct APHA color number, measured on
a solution of 50 g / 70 ml
Methanol 27 12th basic APHA color number 112 39 Freezing point, ⁰ C 154.5 157.0 Gas chromatographic analysis, . ! Percent by weight
2- (2-hydroxyphenyl) -2- (4-hydroxy
pheny 1) propane 0.3 . 0.04 Isomers of p- (2,2,4 ~ irimethyl-
4-chromany1) -phenol 2.7 0.03 Trisphenol
2,2-di (4-hydroxyphenyl) propane
(by forming the difference) 1.0
96.0 0.008
99.92

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BATH

-H-

The gas chromatographic analysis and the determination of the basic APHA color numbers are as described in Example 1 Procedure carried out. The freezing point is according to! ASTM test standard D-1015-55 determined.

^109826/1933 bad original

Claims (14)

' Patent claims Π «Process for the production of high purity 2,2-di - (^ - hydroxyphenyl ) propane, characterized in that a single-phase, liquid mixture of 2,2-di- (4-hydroxyphenyl) propane, phenol and 3 to 48 percent by weight, based on the phenol, of water from an initial temperature of 32 ° C. to a temperature heated, in which an adduct of equimolar proportions of 2,2-Di- (4 - hydroxyphenyl) * - propane and phenol crystallized out, separating the suffered ItriBtalle from the mother liquor and, if necessary after washing with a hight solvent for the 2,2-di- (4-hydroxyphenyl) propane, from the crystals die Phenolic component separates " 2. The method according to claim 1, characterized in that the weight ratio of phenols to 2,2-di- (4-hydroxyphenyl) ~ propane in a single-phase, liquid mixture 0.9: 1 to 10: 1, preferably 1 , 2: 1 to 8: 1, in particular 1.4: 1 here 5: 1. 3 »Process according to claim 1 or 2, characterized in that the single-phase, liquid oil contains up to 46 percent by weight, based on the phenol, of water. 4. The method according to claim 1 bie 3, characterized in i that the starting temperature of a single-phase, liquid mixture in the B * i? eiiin _: ytm £ Z -'Hj 7 * ^ 0, y ^ ttie * white 38> ie ^ t ⁰ C, is ν 5. The method according to claim 1 to 4, characterized in that 109826/1933 that the single-phase, liquid mixture for crystallization of the adduct is cooled to temperatures of 10 to 55 ° C-. 6. The method according to claim 1 to 5, characterized in that that the cooling is carried out with stirring. 7. The method according to claim 1 to 6, characterized in that • that the adduct crystals with before the separation of the phenol Phenol, preferably aqueous phenol. ■ '■ - 8. The method according to claim 1 to 7, characterized in that the separation of the phenol from the adduct crystals by Heating, if necessary, or optionally under reduced pressure, is carried out. 9. The method according to claim 1 to 8, characterized in that a single-phase, liquid Gemiseh is used which by combining a certain proportion of the less pure, t equimolar adduct of 2,2-di- (4-hydroxyphenyl) propane and Phenol, which adduct would provide an insufficiently pure 2,2-di- (4-hydroxyphenyl) -propane after the phenol separation Phenol and water was obtained. 10. The method according to claim 9, characterized in that the impure, equimolar adduct of 2,2-di- (4-hydroxyphenyl) propane and phenol was recovered from a reaction mixture obtained from the condensation of phenol with acetone and contains unconverted phenol and which aur 109826/1933 BATH ORIGINAL Separation of the water, unreacted acetone and volatile Impurities subjected to a distillation and then cooled to temperatures at which the adduct crystallized out, the crystals being finally separated from the mother liquor. 11. The method according to claim 10, characterized in that ■ the phenol and acetone to carry out their condensation in a proportion of at least 3 moles of phenol / mole of acetone into the reaction zone were fed. 12. The method according to claim 10 or 11, characterized in that that the condensation of the phenol with the acetone in the presence of a volatile, acidic catalyst, preferably hydrogen chloride, was carried out. 13. The method according to claim 12, characterized in that the reaction zone also contains a sulfur-containing promoter. 14. The method according to claim 1 to 13 »characterized in that the water from the after the separation of the crystals formed during cooling of the single-phase, liquid mixture from the equimolar adduct of 2,2-di- (4-hydroxyphenyl) propane and remaining phenol / is separated mother liquor and that the thus obtained, substantially anhydrous liquid to a fresh portion of the single phase liquid mixture is added at least partially as Ayffüllmaterial. · 1Q9828 / 1933 BADORlGiNAL ί Λ .. '