BE763512Q - - Google Patents

Description

       

  "Process for the production of biephenols" <EMI ID = 1.1>

  
The present invention relates to the preparation of biaphenola, by reaction of ketones and phenols, which occurs in the presence of a catalyst consisting of a specially conditioned polymer. Bile applies in particular to the preparation of

  
  <EMI ID = 2.1>

  
the name of biephenol A, by condensation of phenol and acetone. The most commonly applied processes use strong mineral acids, such as sulfuric or hydrochloric acid, as a soluble catalyst or condensing agent for this reaction. Water is a by-product of the reaction, and the presence of these soluble and dehydrating acids presents problems which, although not insurmountable, are however costly and sometimes difficult to solve. The presence of water in soluble acid has not only

  
  <EMI ID = 3.1>

  
yields, but dilutes the acid catalyst and forces the aid to be reconcentrated or discarded. The soluble acid comes into contact with all the metals which are themselves in contact with the reaction medium. Important and expensive equipment is therefore required, which

  
  <EMI ID = 4.1>

  
these soluble acids in the product promotes the production of undesirable byproducts, hence contamination of the bisphenol by these byproducts and metallic eels, unless resorting to costly purification processes. Usually, most of these purification processes have to be carried out, in order to separate unreacted phenol, below 150 [deg.] C, if the soluble acid is present, even at l. state of traces. As a result, if distillation is applied, it becomes an expensive process requiring high vacuum.

  
The processes currently used in practice cannot provide industrial quantities of 2,2-bie- (4hydroxyphenyl) -propane with a sufficient degree of purity for all applications. For example, large amounts of

  
  <EMI ID = 5.1>

  
in the flourishing field of epoxy resins and also in the <EMI ID = 6.1>

  
epoxy require a 2,2-bie- (4-hydroxyphenyl) -propane having a purity of at least 92% and applications to polycarbonate and polyhydroxyether resins require as raw material a

  
  <EMI ID = 7.1>

  
It has been found that the presence of more than slight amounts of impurities exerts a detrimental and out of all proportion effect on the quality of these polymers. Known purification methods can improve the quality of commercially available 2,2-ble- (4-hydroxyphenyl) -propane to about 96% purity. This is generally sufficient for epoxy resin applications, but only complex purification processes can provide the high purity 2,2-bie- (4-hydroxyphenyl) -propane needed as a starting material for the manufacture. polycarbonate resins or polyhydroxyethers. In addition, these purification methods are costly in terms of time, equipment and materials consumed.

   In the processes currently used for the manufacture of 2,2-bis- (4-hydroxyphenyl) -propane, phenol is condensed with acetone in the presence of a mineral acid as a condensing agent, or of a carbonate catalyst. condensation. Commonly used, and even preferred in these processes, mineral acids

  
very strong, like sulfuric acid and hydrochloric acid, in spite of the operational difficulties which they present. Even using these powerful catalysts, the known methods require long periods of contact between the reactants and the catalysts. Contact times of between 10 and 16 hours and more are not uncommon. Efforts to shorten the contact time which is, of course, economically important in an industrial process, have heretofore included either additional processing operations or the use of catalyst promoters.

  
For example, it has been proposed to include a digestion stage following the condensation reaction. This device is in essence quite simply a two-stage reaction and it only slightly decreases the contact time compared to an identical reaction carried out without digestion and does not significantly increase the purity of the product above previously obtained levels. Mineral acid catalyzed phenol and acetone condensations are not of interest due to the time required

  
for the reaction and the product obtained is only about 75-92% purity at best. This degree of purity is not at all suitable for

  
a starting material in the manufacture of polycarbonate or polyhydroxyether resins and it is just right, even after

  
that its quality has been improved, as a starting product for the fa-

  
  <EMI ID = 8.1>

  
It is a known fact that the use of catalyst promoters markedly increases the rate of condensation of phenol and acetone to 2,2-bis- (4-hydroxyphenyl) -propane. However, the contamination of the product increases proportionally. The substances which are usually used as promoters of the condensation reaction of phenol and acetone are solid, liquid or gaseous compounds which contain sulfur and which are soluble in the reaction mixture. In all the reactions known so far, these substances or their reaction by-products have invariably been found as impurities in the product. These impurities, which impart both a characteristic odor and a marked 2,2-bis- (4-hydroxyphenyl) -propane color, can only be removed with difficulty, if at all possible.

   The separation difficulties have up to &#65533; present neutralized the advances

  
of view

  
point / speed stages, obtained with promoters used in conjunction with mineral acids as catalysts in known industrial processes. The result is that the methods currently in use compromise either the rate of reaction by excluding the promoters or the purity of the product using them.

  
Due to the fact that we do not currently have large

  
  <EMI ID = 9.1>

  
e <EMI ID = 10.1>

  
The Applicant has discovered a highly satisfactory process for the production of biephenols which reduces or avoids the difficulties of the processes known heretofore. She has found that the condensation of phenols and ketones can be achieved to produce bisphenols by using a polymeric cation exchange resin which is practically insoluble.

   According to the process of the present invention, reacting a phenol, having an active hydrogen atom in the para position relative to the phenolic hydroxyl, with a ketone having at least one methyl group in the alpha position relative to the carbonyl group, the phenol being present in an amount greater than the stoichiometric equivalent and the reaction taking place in the presence of a polymeric cation exchange resin, practically insoluble, which serves as a catalyst, at a temperature of at least 40 [deg.] C.

  
These catalysts are in principle polymeric resins having cation exchange groups chemically bonded to them. Generally, these ion exchange groups are strong acid groups, such as sulfonic groups, which have a strong virtual power of exchange with basic ions,

  
  <EMI ID = 11.1>

  
This catalyst is chemically stable and practically insoluble in the reaction medium at reaction temperatures which can range up to approximately 100 [deg.] C. Its efficiency is to some extent affected by the water formed during the reaction. But the reaction can be carried out until the accumulated water content matches the point where the reaction ceases. The product is then recovered, and the catalyst is regenerated. In addition, the use of the catalyst does not promote the production of by-products which are not intermediates in the reaction for the formation of bisphenols, which simplifies the process of &#65533; purification.

  
  <EMI ID = 12.1>

  
determined primarily by the number of acid groups bonded to the polymeric resin backbone per unit weight. However, the catalytic power of the resin in this process is only partial.

  
  <EMI ID = 13.1>

  
It is also of great importance for these acid groups to come into contact with the reagents.

  
Therefore, to be effective in the application of this method, the acid groups must be on the surface of the resin structure. However, it is not necessary that the resin structure has a shape? particular, although it is desirable to obtain a catalyst before the greatest possible contact surface for the exposure of the greatest possible number of acid groups. It is advantageous that the structure of the catalyst is also

  
  <EMI ID = 14.1>

  
grains in order to increase the total contact surface, or else that this catalyst can be made porous. When using porous polymer structures, the pores should preferably be large enough to allow free passage of large organic molecules, such as bisphenols.

  
The particular polymer structure to which these strong acid groups are attached is not of critical importance to the application of the process. This structure must, however, make the polymer practically insoluble in the reaction medium and in any solvent to which the catalyst might normally be exposed. Highly cross-linked resins provide an effective means of achieving the required insolubility of these resins, although other means, such as crystallization forces, are sometimes strong enough to provide such insolubility without the need for this. reluctant! effective cation. We got big euc-

  
  <EMI ID = 15.1>

  
sulfonic acid.

  
It is generally necessary, for the application of this

  
  <EMI ID = 16.1>

  
acidic or hydrogenated. As some of these resins are sold in salt form or in sodium form, it is necessary to treat this before use, in order to transform the ion exchange groups into their acid form. It is usually easy to

  
  <EMI ID = 17.1>

  
In general, excess acid is used and after regeneration, the excess acid is removed by washing with water, or with a suitable solvent to remove the salts liberated.

  
If, in such a treatment, water is used, it disperses in the resin network, which it swells somewhat.

  
Sometimes a moistened resin is sold to achieve the same effect. The Applicant has observed that the presence of this water in the polymer network of the ion exchange resin has a rather harmful effect on the yield of the catalyst, which it affects. A moistened resin. for example, can hold up to its own weight of water,

  
based on the weight of dry resin. For best results, water should be moved until less than about 1% is left, based on the weight of the resin, so

  
to present the maximum rate of condensation of the ketone groups and of the phenol.

  
resin by operating in organic solvents containing soluble acids, but this leads to a difficult problem of separating the saline by-products by washing with an organic medium.

  
We can achieve the displacement of water by several

  
manners other than neutralization or the use of washing media. For example, to move water, gold. can use phenol

  
and distillation or diffusion processes, or the resin can be dried in an oven or under vacuum. A dried resin, which

  
it has been left to soak for some time in molten phenol, which in its acid form constitutes a very effective catalyst for condensing

  
the phenol and the ketone used in the present process. If most of this water is not displaced, the acidic polymer resin exhibits only a weak catalytic effect. Although the Applicant

  
does not wish to be bound by a particular theory of operation, it believes that the water contained in the network of the polymer catalyst forms an effective screen around the ionic groups attached to the structure of the resin and that it prevents or delays the effect Catalyst for these groups in non-aqueous reaction media. Replacing this partially bound water with phenol greatly increases the availability of these ionic acid groups to such an extent that the resin thus modified becomes a very efficient catalyst.

  
  <EMI ID = 18.1>

  
during the reaction by ease of use of these catalysts <EMI ID = 19.1>

  
polymers, there are no serious problems of corrosion, or dilution of the catalyst due to the release of water during the implementation of this process. The efficiency of the catalyst

  
  <EMI ID = 20.1>

  
better functioning, in continuous operation, by carrying out the reaction until the water content of the reaction mixture

  
  <EMI ID = 21.1>

  
prepared for the desired reaction, by removing water and using a dry, salt-free phenol-oetone feed liquor, the catalyst can be used effectively for long periods of time. To obtain maximum efficiency, however, it is desirable to re-dry this catalyst. The presence of metal salts can also reduce the effectiveness of the catalyst, so that it may be necessary to regenerate it by acid washing.

  
These catalysts are effective in promoting the condensation of phenols having reactive and substantially unhindered hydrogen which is in the para position with respect to.

  
with phenolic hydroxyl. These phenols can have one or more lower alkyl substituents, which are in the ortho and meta position relative to the phenolic hydroxyl, such as for example ortho and metacresol, 2,6-dimethyl-phenol, meta-xylenol, tetramethylphenol, and 2-methyl-6-tert-butylphenol, or else they may be halogen-substituted phenols, such as in particular ortho-and meta-chlorophenoJs and 2,6-dichlorophenol.

  
It is necessary, in the application of the process of the present invention, to operate with quantities of phenol greater than the stoichiometric ratio relative to the ketone, and in general with at least two moles of phenol per mole of ketone. In the acetone-phenol reaction, for example, the molar ratio of phenol to acetone is preferably between 3: 1 and 20: 1. The

  
  <EMI ID = 22.1>

  
phenol to acetone between about 6: 1 and 12: 1, in a continuous process, a somewhat higher conversion rate is obtained per pass, as well as a slightly better yield of acetone. It is possible to use the catalyst of <EMI ID = 23.1>

  
alpha to oarbonyl. It is particularly desirable

  
  <EMI ID = 24.1>

  
The operator prepares and maintains the desired reaction temperature until the water content renders the catalyst inactive or reactivated.

  
  <EMI ID = 25.1>

  
the product can be recovered by filtering off the insoluble ion-exchanged resin, followed by recovery of the product. In continuous operation, the phenol-ketone mixture can be passed over a fixed or moving bed of catalyst at a rate such that the water content of the reaction phase can be kept within tolerable limits. If desired, several stationary beds can be used to continuously remove and regenerate or dehydrate a portion of the catalyst, and then return it to the reaction zone.

  
We have found that these ion exchange resins are generally effective in the acid form at moderate temperatures.

  
  <EMI ID = 26.1>

  
sirable, as by-product formation appears to increase rapidly above this temperature, without a concomitant increase in the rate of bisphenol formation or in yield. In addition, there may be some dissolution of the resin at

  
  <EMI ID = 27.1>

  
tolerable when using liquid acids such as sulfuric acid, because in the latter case the formation of sub-

  
  <EMI ID = 28.1>

  
With solid polymer resins containing solidly attached acid groups, temperatures are preferably applied *

  
  <EMI ID = 29.1>

  
tion increases with an increase in temperature, but at the same time the formation of by-products may also increase.

  
  <EMI ID = 30.1>

  
a high rate of transformation without blocking the column or crystallizing the phenolic complex in the apparatus. However, in continuous operations, temperatures can be applied

  
  <EMI ID = 31.1>

  
The pressures applied do not appear to have a critical influence in the performance of the process. Atmospheric pressure seems to be the most comfortable in general. but an increase in pressure may be highly desirable. One can also apply

  
  <EMI ID = 32.1>

  
gives a slightly higher pressure to compensate for the pressure drop due to the resistance of a compact bed to flow

  
  <EMI ID = 33.1>

  
not necessarily critical in discontinuous operation. The bisphenol produced is generally not affected by prolonged contact with the catalyst. Phenol, acetone and bisphenol A, for example, as well as limited amounts of water, can be in contact with a catalyst saturated with phenol for extended periods of time and allow recovery of commercially appreciable amounts. economical 2,2-bis- (4-hydroxyphenyl) propane. The reactants not separated, after dehydration, can be recycled.

   In general, at a reaction temperature between 50 and 100 [deg.] C, the optimum contact time depends mainly on the amount of polymer catalyst, its acidity, its state or porosity, its capacity to ion exchange and the specific amount of reactants and water formed during the reaction. With an equal degree of exchange capacity and porosity, a few batches of catalyst perform better, so that in the final analysis the selection of the most desirable catalysts for use in the present process is effected by steps of. 'test of sufficient duration to indicate the appro-

  
  <EMI ID = 34.1>

  
lyser, to achieve a stable level of production.

  
When such a catalyst is used in batch mode, a catalyst initially saturated with dry phenol, placed in a dry feed liquor, will produce for the case of a total conversion about 1 kg of bisphenol per kg of dry catalyst before that the water content does not create difficulties. The catalyst can then be separated by filtration, washed and dried, suspended in dry phenol to have it ready for a new application. Such a cycle can be repeated indefinitely, unless traces of alkalis or metal ions block the acid groups attached to the catalyst. The catalyst which has become inactive can then be regenerated, if desired, by the action of an acid, then washed, dried and treated again with phenol, in order to have it ready for a new application.

   Excessive wear and high heat should be avoided when performing such regeneration.

  
In the case of a fixed bed column, operating continuously or semi-continuously, the ratio between equivalents of catalyst and moles of ketone is fixed by the ratio between the ion exchange power and the bulk density, thus than the porosity of the reain. The flow rate of the reagents must be adjusted as a function of the percentage of transformed ketone which is desired to be obtained in each cycle. In general, the Applicant prefers to operate continuously so as to obtain a sufficient duration of presence of the reagents in the column in order to ensure a degree of conversion for acetone.

  
  <EMI ID = 35.1>

  
If desired, it is possible to operate continuously at any desired acetone conversion rate per pass, depending on the economic conditions which it is desired to impose on the process.

  
The recovery of the product obtained by this process is relatively easy and it can be done according to several processes. In batch operation, it appears that a suitable method of separating bisphenol-A is crystallization of the phenolic complex after separation of the insoluble polymeric catalyst. The original catalyst, or the fine particles to which it gave rise, can be separated by filtering the reaction medium at a temperature above the point of crystallization of the phenolbisphenol-A complex, for example at 65 [deg.] C, while cooling the filtrate to precipitate this complex, for example at a temperature of

  
between 40 and 65 [deg.] C. and recovering the purified crystals of phenol-bisphenol-A complex. This complex can then be distilled to obtain the bisphenol-A as a residue, which gives a dry distilled phenol ready for recycling. The bisphenol-A residue is generally of very good commercial quality and often reaches a purity of at least 95%. The other bisphenols produced by application of this process can be separated from the unreacted ketone and phenol by crystallization or precipitation techniques. Although some dissolved bisphenol, as well as most by-products, may remain in the filtrate after application of these separation methods, distillation or any other suitable method can be used to recover the bisphenol. as well as the phenol to be recycled.

  
The following examples are an illustration of the process.

Example t

  
Phenol and acetone are mixed in the molar ratio of 10 moles of phenol per mole of acetone, and this mixture is sent by a pump through a glass column 254 cm long,

  
  <EMI ID = 36.1> free acid, and displacement of the remaining water by means of phenol by azeotropic distillation. This distillation was carried out by adding 2000 g of phenol to the washed ion exchange resin, and heating the mixture at S5 [deg.] C for one hour under a pressure of 20 mm of mercury to drive off the water. by distillation, at the same time as an azeotrope of water and phenol passes.

  
The column saturated with phenol is maintained at a temperature of 75 [deg.] C + 0.5 [deg.] C, and the operation is carried out continuously for fourteen hours, the flow rate of almost dry phenol and acetone being maintained between 630 and about 650 g per hour, except during the first three hours, where 734, 703 and 678 g per hour were passed respectively. We

  
  <EMI ID = 37.1>

  
is the effluent of the first and second hour; he wakes up at

  
1,437 g. Sample B is the effluent of the fifth and sixth hour, it amounts to 1247 g. Sample C is the thirteenth and fourteenth hour effluent, amounting to 1,288 g.

  
Each of these samples is treated identically. The sample is cooled with stirring to 27 [deg.] C to precipitate part of the phenol and the 2,2-bie- (4-hydroxyphenyl) propane complex mixed with phenol, and filtered through a funnel containing a sintered glass plate. The filter cake is compressed, and vacuum dried under a mercury pressure of 15-20 mm, and then weighed. The crystalline product recovered from sample A weighs 338 g. That obtained from sample B weighs 208 g;

  
  <EMI ID = 38.1>

  
The filter cake is washed with a total of 150 ml of distilled water to remove free phenol; the operation is carried out by washing several times and drying by suction under vacuum, as indicated above. The dried filter cake is distilled with a temperature

  
  <EMI ID = 39.1>

  
does not contain renin = by-products. Its melting point is between 155 and 157 [deg.] 0.

  
  <EMI ID = 40.1>

  
  <EMI ID = 41.1> an oily layer. The oily layer, which is mainly phenol, is distilled at a vessel temperature of 2000C under 0.2 mm of mercury. A new quantity of 2,2bis- (4-hydroxyphenyl) -propane is thus obtained in the distillation residue, which amounts respectively to 15 g, 9.5 g and 13.5 g for samples A, B and C. .

  
The mother liquor from the first filtration is distilled with a vessel temperature of 200 [deg.] C. under a pressure of 0.2 mm of mercury, after taking a small sample for determination of acetone. An aliquot of the distillation residue is recrystallized from an equal weight of toluene, the crystalline 2,2-bis- (4-hydroxyphenyl) -propane is recovered and dried. The weight of this product contained in the whole mother liquor is then calculated, and one finds a content of 42 g, 49 g and 53 g of 2,2-bis- (4-hydroxyphenyl) -propane, respectively, in samples A, B and C.

  
The following table summarizes the results for the three samples.

  

  <EMI ID = 42.1>

Example 2

  
  <EMI ID = 43.1>

  
but by modifying the molar ratio between phenol and acetone and the contact time. We get the following results

  

  <EMI ID = 44.1>

Example 3

  
The conditions and procedure of Example 1 are repeated, but by modifying the temperature of the column and the contact time. The following results are obtained:

  

  <EMI ID = 45.1>

Example 4

  
Example 1 is repeated, but modifying the contact time. The following results are established:

  

  <EMI ID = 46.1>

Example 5

  
The operating conditions of Example 1 are repeated, while modifying the contact time and the water content of the reaction mixture. The following results are obtained:

  

  <EMI ID = 47.1>

Example 6

  
  <EMI ID = 48.1>

  
of phenol and 250 g of dehydrated catalyst and treated as indicated in Example 1. The catalyst is separated by filtration at

  
  <EMI ID = 49.1>

  
mercury. The residue, mainly 2,2-bis- (4-hydroxyphenyl) propane, weighed 137 g. This weight corresponds to a transformation rate

  
  <EMI ID = 50.1>

Example 7

  
We pass through the equipment of example 1 a

  
  <EMI ID = 51.1>

  
at a flow rate ensuring a contact time of forty-seven minutes. 5.6% of the acetophenone is converted into bisphenol (melting point:
180 - 184 [deg.] C).

Example 8

  
We pass through the equipment of Example 1,

  
  <EMI ID = 52.1>

  
at a flow rate allowing a contact time of 41.5 minutes. The conversion of 16.0% of acetone to the bisphenol of oresol is obtained.

Example 9

  
  <EMI ID = 53.1>

  
the

  
toluene, and washed with water to separate a few suspended catalyst particles. The toluene solution is distilled, after washing, at 200.degree. C. and at 0.25 mm of mercury. The residue, <EMI ID = 54.1>

  
no more free acid, and dehydrating the water-swollen polymer by azeotropic distillation of the water with phenol. The excess phenol is filtered off, which leaves the catalyst ready for use.

Example 10

  
  <EMI ID = 55.1>

  
oyclohexanone, 643 g of o-chlorophenol and 130 g of catalyst
(DOWEX 50 X-4, trade mark le for a sulfonated exchange renin

  
  <EMI ID = 56.1>

  
washing and distilled at 200 [deg.] C under 25 mm of mercury. The residue, mainly 1,1-bis- (4-hydroxy-3-chlorophenyl) -cyclohexane, weighs 30 g. This weight corresponds to a rate of transformation of cyclo-

  
  <EMI ID = 57.1>

  
The Applicant has also found that the catalytic efficiency of the resin is significantly increased by partially esterifying it with a marcapto-alcohol.

  
Therefore, according to the present invention, a process for making bisphenole by reacting a phenol having a hydrogen atom in the para position with respect to the hydroxyl group of the phenol with a ketone having at least one methyl group in the alpha position with respect to the. carbonyl group, the phenol being present in excess of the stoichiometric amount of the reaction carried out

  
in the presence of a practically insoluble cation exchange resin serving as a catalyst, is characterized in that this cation exchange resin is partially esterified by means of a mercapto-alcohol.

  
The insoluble cation exchange catalyst of the present invention provides a rapid rate of reaction between the phenol and the ketone and leaves no contaminants or odor capable of affecting the quality of the bisphenol produced. We thus avoid stages <EMI ID = 58.1>

  
notably the production spawns.

  
The catalysts used herein can be prepared.

  
  <EMI ID = 59.1>

  
ture of this renin, but one can also influence or confer this Insolubility by acting on other factor @, such as the molecular weight and / or the degree of criatallinity of the resin or the polymer.

  
However, the chemical structure of the polymer or resin backbone is not critical to the operation of the catalysts of the present invention. For example, these re-

  
  <EMI ID = 60.1>

  
sulfonated resins of cross-linked styrene, sulfonic acid resins derived from formaldehyde-phenol, sulfonic acid resins derived from formaldehyde-benzene. The only specifications critical and necessary for their operation are their insolubility, the possession of a cation exchange power and a

  
  <EMI ID = 61.1>

  
The ion exchange power of these resins is determined by the number of cation exchange groups bound to the polymer structure. This is generally referred to as "capacity

  
  <EMI ID = 62.1>

  
of these resins by their "exchange capacity" expressed in milliequivalents per gram of dry resin, or this capacity can be determined by passing a solution of a salt such as NaCl through a resin sample and titrating the effluent solution. We then calculate the exchange capacity from the formula:

  

  <EMI ID = 63.1>


  
where ml is the number of milliliters of titration liquor added, N is the normality of this liquor, and P the weight of the e-

  
  <EMI ID = 64.1>

  
However. a more precise oriter of the effectiveness of a

  
  <EMI ID = 65.1>

  
The "exchange rate" is the number of cation exchange groups available for contact with the reagents. Contact of the ion exchange resins with the reagents does not occur.

  
  <EMI ID = 66.1>

  
Renin providing maximum surface area is highly desirable. For example, a finely ground resin or fine beads or microspheres preferably having a porous nature, can serve to provide the greatest possible number of groups available for this ion exchange.

  
The Applicant particularly prefers resins having a high exchange capacity for basic ions, and particularly those which have an exchange capacity of at least

  
2 milliequivalents per gram. However, it is possible to use in the implementation of the process of the present invention resins of which

  
  <EMI ID = 67.1>

  
The resins have a large number of strong acid groups chemically bonded to the residues of the polymer, and we particularly prefer resins having sulfonic acid groups.

  
While one would expect that the effectiveness

  
  <EMI ID = 68.1>

  
that the catalytic efficiency of the resin thus prepared is greater

  
  <EMI ID = 69.1>

  
efficiency is particularly increased when esterified by 3

  
  <EMI ID = 70.1>

  
  <EMI ID = 71.1>

  
ions, it is found that the reaction rates between phenol and ketone decrease proportionally as the

  
  <EMI ID = 72.1>

  
esterify between 5 and 15% of all available cation exchange groups, since it has found that such resins are the most effective catalysts for the implementation of

  
the present invention. We can easily determine the percentage

  
of esterified groups by measuring the exchange capacity before and after esterification, and by determining the percentage difference. This percentage constitutes a reasonable equivalent of the degree of esterification by the mercapto-alcohol.

  
The mercapto-alcohols for esterifying the cation exchange resins of the present invention are aliphatic hydroxythiols containing at least one hydroxyl group and at least one / mercapto group, although they may have additional hydroxyl and mercapto groups. The Applicant particularly prefers (lower alkyl) mercapto-alcohols (hydrcxy-alkylthiols) containing from one to six carbon atoms in the alkyl group. Mercaptoethanol. mercapto-propanol and mercaptobutanol provide particularly good results.

  
Esterification of the cation exchange groups of the resin is easily accomplished without requiring the addition of a high temperature catalyst or other type of catalyst, although a catalyst can be used if desired. Preferably, the Applicant slowly adds the mercapto-alcohol to an anhydrous and fluid mixture containing the resin, preferably in an inert and neutral organic solvent such as, for example, heptane, benzene and the like. Stirring in the fluid medium causes good mixing of the mercapto-alcohol and allows uniform partial esterification! through the entire mass of the resin without localized areas of total esterification, which could inactivate some particles of the ion exchange resin.

  
In order for esterification to take place and for the catalyst to exert an effective action on the reaction of the present invention, it is necessary that the cation exchange group be formed.

  
  <EMI ID = 73.1>

  
such resins, it is necessary to regenerate the balance by washing the resin with an acid. With * sulfonated resins *, for example, we prefer washing with a sulfuric acid solution, although other acids can be used if desired to effect this regeneration. The soluble salts formed during this regeneration can be removed from the resin by additional washes of the resin with water or with other solvents.

  
Before using these esterified cation exchange resins for the condensation of phenols with ketones, it is necessary, in order to obtain the maximum reaction yield, that the resin be practically anhydrous, that is to say that it contains less from 2 to 3% water by weight. It has been found that the presence of an amount of water greater than these 2 or 3% in the reaction zone seriously decreases the reaction rate and the bisphenol yields when carrying out the present process. Since water is a by-product of the reaction, the amount of water present needs to be carefully regulated and controlled.

  
The dehydration of the resin is easily carried out before or during use by various means. Heating to dryness in an oven or heating with an agent generating an azeotrope with water is a satisfactory means. The Applicant has also found that immersing the resin in phenol or heating a mixture of phenol and resin constitutes a particularly advantageous means of dehydrating the resin. It is also possible during the performance of the process to carry out the reaction with a high flow rate and a low conversion rate per pass so as to obtain practically anhydrous conditions for the subsequent passes. This is why the Applicant prefers to conduct the reaction of the phenol and of the ketone until a level of conversion is obtained.

  
  <EMI ID = 74.1>

  
continuous reaction of the resin serving as a catalyst while maintaining substantially anhydrous reaction conditions, i.e. this procedure limits the water content to less than 2 to 3% and

  
  <EMI ID = 75.1>

  
which is most desirable.

  
The present catalyst is an effective promoter of the reaction between a ketone and phenols having a hydrogen atom.

  
  <EMI ID = 76.1> The phenols used can have one or more substituents in the ortho position and / or in the meta position with respect to the phenolic hydroxyl, such as for example alkyl groups, a halogen or other similar non-reactive groups. As examples of such

  
  <EMI ID = 77.1>

  
meta-xylenol, tetramethylphenol, 2,6-di-tert-butylphenol and other alkylated phenols as well as halogenated phenols such as ortho- and meta-chlorophenols and 2,6-dichlorophenol. The substituents on the phenolic nucleus must be such that they do not prevent or alter the reactivity of the hydrogen atom placed in the para position with respect to the phenolic hydroxyl. The Applicant particularly prefers the phenol itself.
(C6H50H) as a phenolic reagent.

  
As a ketone, the Applicant prefers to use acetone,

  
  <EMI ID = 78.1>

  
relative to the carbonyl group are also of interest and can be used to carry out the process. For example, ketones having aliphatic or aromatic substituents, such as methyl ethyl ketone, methyl propyl ketone, acetophenone and methyl vinyl ketone, can be used. Cyclic ketones can also be used, for example cyclohexanone.

  
The reaction proceeds readily when there is an amount of phenol slightly greater than the stoichiometric amount relative to the ketone present in the reaction zone and in contact with the esterified resin serving as a catalyst. It is generally beneficial to have 3 moles of phenol per mole of ketone, although up to. 20 moles of phenol, or more, per mole of ketone. However, the use of phenol in amounts greater than those corresponding to the above-mentioned ratios does not provide any additional advantage in reaction speed or ease of implementation, and the process even becomes somewhat uneconomical. The Applicant prefers, in order to ensure the highest conversion rates and the greatest reaction yield, to use molar ratios between phenol and

  
  <EMI ID = 79.1>

  
The time required for the reaction depends to a large extent on the molar ratio of phenol to ketone, the exchange capacity of the resin, the degree of esterification, the reaction temperature, the desired rate of transformation per pass and the water content of the reaction mixture. With the preferred limits stated above, a residence time of 20 to 60 minutes generally provides an approximate level of 50% transformed ketone.

  
The present catalyst is suitable for continuous or discontinuous operation. Continuous operation on a fixed resin bed can be achieved by operating most satisfactorily at temperatures between 70 and 98 [deg.] C. High rates of conversion of phenol and ketone to bisphenol are not easily achieved

  
at temperatures below 65 [deg.] C due to the crystallization of phenol and bisphenol in the apparatus, which causes column blockage. Lower temperatures, down to 40 [deg.] C, are however satisfactory for batch productions.

  
Pressure does not appear to be of critical importance in the process of the present invention, and although atmospheric pressure is most suitable, pressures above or below atmospheric pressure can be used if desired. The resistance to flow offered by a packed bed of ion exchange resin used in a column operating

  
in continuous operation requires at the inlet of the column a pressure which is slightly higher than that prevailing in the enclosure of the column, although it is possible to use a flow by gravity.

  
The recovery of the biephenol produced by the process of the present invention is simple and can be carried out in several ways, for example by filtering the reaction mixture to remove the solid catalyst at a temperature above 65 [deg.] C. To recover the bisphenol or bisphenol-phenol complex crystals, the catalyst-free filtrate can be cooled to between 40 and 65 [deg.] C, filter the crystalline bisphenol and distill preferably so as to obtain a dry and recyclable phenol distillate. and a residue of

  
  <EMI ID = 80.1>

  
filtrate some bisphenol, phenol and most of the resinous reaction by-products; they can be recovered by recycling, distillation, crystallization or by other suitable means.

  
  <EMI ID = 81.1> without particular stages of purification, very high purity, generally 95 to 98%, and not contaminated by odors or traces of catalysts or by-products. Similarly, the yields are proportionately high and significantly higher than those resulting from the action of the unesterified resin.

  
The following examples illustrate the present invention:

  
  <EMI ID = 82.1>

  
A cation exchanger resin of cross-linked and sulfonated polystyrene is dried at 75-85 [deg.] C until its water content is.

  
  <EMI ID = 83.1>

  
with N-heptane (boiling point: 9800). The heptane remaining in the moisture-free resin is evaporated by heating the resin.

  
  <EMI ID = 84.1>

  
To determine the resin exchange capacity, about 20 grams of dry resin is carefully weighed into a 50 ml beaker and washed with distilled water; we introduce resin and distilled water

  
  <EMI ID = 85.1>

  
fitted with a shut-off valve. The wetted resin is allowed to swell to 200 to 300% of its original volume before pouring it into the column.

  
400 g of a solution are passed through the resin bed.

  
  <EMI ID = 86.1>

  
per minute, and the effluent is collected in a graduated flask of

  
1 litre. Initially, the effluent is acidic because the Na + ions drive the H + ions from the aulfonic acid groups bound to the backbone of the polystyrene resin. Replacement or exchange of all

  
  <EMI ID = 87.1>

  
sunflower. At this time, the exchange is complete. The resin thus exchanged is washed with distilled water; the effluent is made up to 1 liter with distilled water. A 25 ml aliquot of effluent is titrated with a titrated 0.1 N NaOH solution, using phenolphthalein as an indicator. It is thus determined that the weight of

  
  <EMI ID = 88.1>

  
ends the exchange capacity by the following calculations:
25 ml aliquot = 24.40 ml 0.1017 N NaOH
  <EMI ID = 89.1>
 
  <EMI ID = 90.1>
 The previous procedure is repeated using a poly-

  
  <EMI ID = 91.1>

  
eultate showing the total exchange capacity of the two resins used.

  
by the preceding determination, one obtains the exchange capacity of the resin, or the number of eultonic acid groups present in the cation exchange resin.

  

  <EMI ID = 92.1>


  
The resin, the exchange capacity of which has just been determined, is mixed with 1.25 times its weight of normal heptane and the mixture is heated to a boil with stirring under reflux until no more is seen. water separating in the water trap. Having thus ensured anhydrous conditions, there is a resin ready for the esterification stage.

  
A sufficient quantity of mercapto-alcohol is added dropwise to esterify 5 to 15% of the sulfonic acid groups of the resin, and the water of reaction is collected in a trap located on the reflux circuit. When the reaction is complete, as indicated by the stoichiometric amount of water collected, the esterified resin is filtered, washed several times with normal heptane and dried at 75 to 85 [deg.] C. We determine according to the mode

  
  <EMI ID = 93.1> <EMI ID = 94.1>

  
following formula

  

  <EMI ID = 95.1>


  
  <EMI ID = 96.1>

  
  <EMI ID = 97.1>

  
of mercury. The resulting solid product contains 60 to 65% of

  
  <EMI ID = 98.1>

  
as a surface coating.

  
The catalyst is added to a mixture of phenol and acetone

  
  <EMI ID = 99.1>

  
slow catalyst hydrogen per mole of acetone. The reaction mixture is heated while stirring, under reflux at temperature

  
  <EMI ID = 100.1>

  
for the periods of time indicated in the table, and varying from one to five hours. At the end of this time, the catalyst is filtered off from the reaction mixture and washed with one mole of phenol. The filtrate plus the washing liquid is then distilled off at
200 [deg.] C under a vacuum of 0.5 mm Hg. Bisphenol is obtained as residue, which crystallizes on cooling. The table below shows the yield in percent of bisphenol for various reaction times and temperatures with esterified catalysts.

  
  <EMI ID = 101.1>

  

  <EMI ID = 102.1>


  

  <EMI ID = 103.1>
 

  
  <EMI ID = 104.1>

  
The comparison of tests N [deg.] 11 and 12 shows that when the other factors are kept constant, a degree of eerification as low as 3% provides a significant increase in the percentage of yield, or in other words an increase. important reaction rate. The results of tests 11 and 13 show the effect of the reduction in the duration on the yields obtained with a catalyst which has not undergone esterification. A comparison of tests N [deg.] 11 and 14 indicates that a resin esterified at 3% provides yields equivalent to those obtained with a double contact time in the case of a non-esterified resin.

  
Tests N [deg.] 15, 16 and 17 demonstrate that higher yields are obtained with the esterified catalyst even when the reaction time is greatly reduced, which ordinarily should reduce

  
  <EMI ID = 105.1>

  
The gradual increase in yield which can be obtained with a gradual increase in the degree of esterification is evident if we consider tests N [deg.] 18, 19, 20 and 21. Keeping constant the other factors such as As temperature, molar ratio and time, increasing the degree of esterification causes the increase in yield. Test N [deg.] 21, which constitutes a preferred embodiment, gives yields comparable to those of any other known process. Esterification to about 20% is a maximum because above this value the decrease in the number of cation exchange groups has an unfavorable influence on the catalytic efficiency of the resin.

  
It is important to note that the bisphenol obtained as a residue in the above examples is free from any trace of catalyst or promoter, and is suitable for very delicate applications without requiring subsequent purification.

  
The present invention further provides a continuous process

  
  <EMI ID = 106.1> <EMI ID = 107.1>

  
the stoichiometric amount, in the presence of a substantially insoluble cation exchange resin as a catalyst, consists of contacting the phenol with acetone under substantially anhydrous conditions, in a reaction zone in the presence of the resin, at a temperature of 30 [deg.] C to 125 [deg.] C, separating the effluent from the reaction zone into two streams, one stream containing 2,2bis- (4-hydroxyphenyl) -propane, adduct 2 , 2-bis- (4hydroxyphenyl) -propane-phenol, reaction byproducts and phenol and the other stream containing acetone, water and

  
phenol, removing the reaction by-products from the first stream, recovering 2,2-bis- (4-hydroxyphenyl) -propane, and recycling the reaction by-products, phenol and acetone to the reaction zone.

  
The dimensions of the reaction zone are not critical, provided the appropriate contact of the reactants with the cation exchange resin is obtained. Suitable reaction zones, for example, consist of large cross-sectional areas such as reaction chambers, tank or autoclave and small cross-sectional areas such as tubular reactor and coil. A large number of reaction zones connected in series or in parallel can be applied in the present invention. Advantageously, these zones are provided with devices for adjusting or maintaining the temperature and with means for preventing the catalyst from being entrained in the effluent.

  
The residence time of acetone and phenol in the reaction zone can vary to a very large extent depending on the specific molar ratio of the reactants, the amount and type of cation exchange catalyst applied, the temperatures applied, the percent desired conversion rate, etc. The residence time, as a minimum time, is the time sufficient to initiate the reaction and, as a maximum time, the time sufficient for a substantially complete interaction between the reactants present. We prefer a 20% conversion of the reactants as a minimum and an 80% conversion as a maximum. Bile in particular prefers

  
  <EMI ID = 108.1> .ion causes the reaction rate to drop rapidly and <EMI ID = 109.1>

  
of product per unit of time. No residence time is critical in the present invention with respect to yield, the same extremely high yields being obtained with relatively short contact times and with low conversions and with long contact times and high conversions. Contact times

  
  <EMI ID = 110.1>

  
better, given that they provide yields of 99% of the theoretical yield, relative to the acetone consumed, of 2,2-bis-
(4-hydroxyphenyl) -propane, having extremely high purity.

  
The phenol applied here is only for the phenyl hydroxide, and the acetone applied here is for the dimethyl ketone only.

  
The process of the present invention is preferably carried out with more than 2 moles of phenol per mole of acetone present in the

  
  <EMI ID = 111.1>

  
per mole of acetone. Higher phenol / acetone ratios, i.e. about 12: 1 or more, are suitable when the temperature of the reaction zone becomes relatively low, as this prevents the build-up in the reaction zone of solidified reaction products or crystallized adducts of phenol with the products of the reaction. A ratio of 6: 1 to 12: 1 of phenol to acetone is particularly suitable.

  
At a conversion of 50% based on the acetone consumed, a phenol / acetone ratio of 10: 1 is particularly preferred. While small amounts of substantially inert solvents, such as pentane, cyclohexane or benzene do not completely inhibit the reaction, they make the separation phases complicated in the process and their presence is not particularly desired.

  
It is essential to maintain high rates of training

  
  <EMI ID = 112.1>

  
substantially anhydrous, i.e. containing less than 2.0% by weight of water, are charged to the reaction zone, since the overall efficiency of the process of the invention depends on the presence of less 2.0% water in the reaction zone for optimum catalysis with cation exchange resins -

  
The temperature in the reaction zone should be such

  
  <EMI ID = 113.1>

  
low will be the temperature applied in the reaction zone, the more

  
  <EMI ID = 114.1> <EMI ID = 115.1> so as to avoid the blockage of the column by solidified 2,2-bis- (4hydroxyphenyl) -propane or its adduct crystallized with phenol. Application of temperatures so high as to degrade the 2,2-bis- (4-hydroxyphenyl) -propane reagents or cation exchange resin, or which produce an undesirable rate of by-product formation is to avoid. The specific temperature applied can vary between 30 [deg.] C and 125 [deg.] C depending on the other operating conditions in the reaction zone, such as the percentage of conversion per pass, the residence time or the contact time between catalyst and reactants and pressure. In order to avoid the obstruction of the reaction zone by solidified reaction products, which can happen

  
  <EMI ID = 116.1>

  
Reasonable rates of conversion to 2,2-bis- (4-hydroxyphenyl) -propane, preferred temperatures are between 40 [deg.] C and 100 [deg.] C.

  
Optimal results in both reaction rate and yield are obtained by applying

  
  <EMI ID = 117.1>

  
preferably sequent these temperatures. The reaction zone can work at atmospheric pressure or at pressures lower or higher than atmospheric pressure. Also within the scope of the present invention is the fact of applying an inert atmosphere in the reaction zone. In general, the application of atmospheric pressure or a slightly elevated pressure is preferably suitable to ensure the proper flow of materials through the system in continuous operations.

  
Another advantage of the present invention is that one should not apply a pressure greater than atmospheric pressure in the reaction zone to maintain the concentration of the catalyst at the desired value during operation as one should. with the already known processes which apply inorganic acid catalysts in the gaseous or vapor state and sometimes catalyst promoters in the gaseous or vapor state.

  
Cation exchange resins are applied as solid state catalysts in the continuous process of the present invention. These resins are insoluble in the reaction mixture and therefore the problem of separation of the gas is avoided. <EMI ID = 118.1>

  
remains in the reaction zone and does not appear elsewhere in the equipment used for carrying out the process. Its duration of use in this process is almost infinite and does not present the need for regeneration. Care is taken to avoid the admission of ions of basic metals, such as sodium, potassium, or

  
  <EMI ID = 119.1>

  
resin ion exchange groups. The use of the insoluble catalyst provides the following additional advantages (1) elimination of the need to apply a corrosion resistant material.

  
  <EMI ID = 120.1>

  
thiseairea the neutralization phases which are common to other processes.

  
Ion exchange resins useful in the present process consist of substantially insoluble polymeric structures with acidic cation exchange groups chemically attached thereto. The exchange potential of the attached acid groups and their number available to come into contact with the phenol and acetone reaction mixture determines the catalytic efficiency of a particular ion exchange resin. Thus, although the number of acid groups attached to the polymer structure of the resin determines the theoretical "exchange power", a better criterion of the catalytic efficiency is the number of acid groups available for contact with the reactants. This contact can only take place at the surface of the resin; therefore, a form of resin which provides a

  
  <EMI ID = 121.1>

  
is highly advantageous and provides the highest rate of reaction and reaction economy in this process. The particular form

  
  <EMI ID = 122.1>

  
Ion exchange resins should be practically

  
  <EMI ID = 123.1>

  
which resin can be applied. The insolubility of the resin generally results from a high degree of crosslinking in the resin but may be due to other factors, such as high molecular weight or high degree of crystallization.

  
  <EMI ID = 124.1>

  
be converted into the hydrogenated or acidic form before their application in this process. The conversion can conveniently be effected by washing the resin with a solution of a suitable acid. For example

  
  <EMI ID = 125.1>

  
salt.

  
Often it happens as a result of either the washing operation indicated above or the manufacturer's packaging process. that the

  
  <EMI ID = 126.1>

  
se of ions in the process of the Applicant. Appropriate techniques

  
  <EMI ID = 127.1>

  
  <EMI ID = 128.1>

  
anhydrous conditions does not need to be treated again at any time during the implementation of the method. Follow-

  
  <EMI ID = 129.1>

  
admission into the apparatus for carrying out the process, simply by passing the reaction mixture through the catalyst <EMI ID = 130.1>

  
  <EMI ID = 131.1>

  
and by phenol.

  
The Applicant has found that the oatalytic efficacy of

  
  <EMI ID = 132.1>

  
Equivalently activated mineral acid analyzers. The conta-

  
  <EMI ID = 133.1>

  
  <EMI ID = 134.1>

  
the advantage resulting from a markedly accelerated reaction rate disappears by contamination of the product.

  
All the advantages of an activated reaction can be obtained without simultaneously causing any contamination of the product, by partial esterification of the cation exchange groups attached to the reticular structure of the polymer resin, by means of a mer-

  
  <EMI ID = 135.1>

  
resin cation exchange groups. This activated catalyst according to the invention is preferably applied because of the faster reaction rate and the absence of odor or other sulfur contamination of 2,2-bie- (4-hydroxyphenyl) -propane prepared with the

  
  <EMI ID = 136.1>

  
of partially esterified ion-exchanged resin is described above.

  
Remarkable yields and savings per kg of catalyst are made possible by the application of these solid ion exchange resins. Experimental tests show that the resins retain their catalytic efficiency for unlimited periods of time. 300 kg of 2,2-bis- (4-hydroxyphenyl) -propane are obtained, <EMI ID = 137.1>

  
catalytic activity. Thus, with the resins described above, a continuous and automatic process can be carried out without any problem of catalyst regeneration.

  
To start the reaction, the phenol and the acetone are heated,

  
  <EMI ID = 138.1>

  
water by weight as maximum and preferably in the dry state, that is to say less than 0.2% water by weight, at the reaction temperature and pass them through a fixed bed of exchange resin of cations, preferably from top to bottom, under low pressure to maintain an appropriate rate of flow through the bed, although gravity flow through the column is also suitable.

  
The effluent from the catalyst bed passes through a concentration apparatus, which can be any film type vaporizer, preferably one operating with a liquid-vapor countercurrent and in which all water and water are removed. acetone and a portion of the phenol as an overhead.

  
Depending on the temperature of the effluent from the reactor and the pressure applied in the concentration apparatus, the reaction mixture may be heated or cooled so as to cause the evaporation of all the water of reaction, and of the acetone.

  
  <EMI ID = 139.1>

  
a certain amount of phenol vapor, leaving as a residue 2,2-bie- (4-hydroxyphenyl) -propane, phenol and by-products. The temperature of this concentration should not be so high as to decompose 2,2-bis- (4-hydroxyphenyl) propane and the reaction preferably takes place at a temperature below.

  
  <EMI ID = 140.1>

  
such that practically complete evaporation of the acetone and of the water is obtained, leaving at least one mole of phenol per mole of 2,2-bis- (4-hydroxyphenyl) -propane, and preferably 4 at
10 moles of phenol, in the residue as well as practically all of the by-products and 2.2-bis- (4-hydroxyphenyl) -propane.

  
The concentration of the effluent simplifies the recovery of

  
  <EMI ID = 141.1>

  
product and allows its composition to be monitored. This determination of the amount of phenol in the composition can be used to raise the crystallization point of the adduct, and thereby facilitate washing of the adduct with dry phenol at a desirable temperature. The concentration also serves to isolate the portion of the product stream containing the water, and the dehydration can then be carried out by distillation at any suitable temperature or time.

  
The top fraction comprising acetone, water and phenol, coming from the device to be concentrated, circulates in a dehydration zone to remove the water leaving the acetone and the phenol which are recycled. in the process. The Applicant has found that this dehydration can be carried out in an improved manner by bringing the mixture of acetone, water and phenol into contact with an ascending stream of dry acetone vapors. This avoids the addition of another component in the reaction process and allows the recycling of phenol and anhydrous acetone. In this process, the mixture is admitted laterally into the column and anhydrous acetone is introduced at the bottom of the column which is preferably maintained at a temperature between 155 [deg.] C and 165 [deg.] C, at atmospheric pressure.

   Dry acetone rises in the column in contact with the feed and effectively removes water therefrom. The wet vapors containing acetone are taken from the top of the column which is advantageously maintained at a temperature of 58 [deg.] C when the atmospheric pressures are carried out by adjusting the reflux ratio. The temperature control at the top of the column is necessary to ensure that an acetone-water distillate without phenol passes to the second column where the water is removed by fractional distillation. The recovered dry acetone is recycled.

  
The residue from the first column and consisting of anhydrous phenol and acetone is recycled.

  
The water from the residue can be discarded from the second column without the need for further purification.

  
  <EMI ID = 142.1>

  
a triphenol, is fed into a crystallization sound. "Crystallization can be carried out by cooling the residue from the concentration apparatus to a temperature below the melting point of the adduct, between

  
  <EMI ID = 143.1>

  
lization varies according to the operating conditions in the concentration apparatus. By distillation of more or less phenol, the phenol / product molar ratio can be adjusted in the feed to the crystallization zone. Phenol in excess of one mole per mole of 2,2-bis (4-hydroxyphenyl) propane absorbs the intermediate by-products, all of which are soluble in phenol in the range of

  
  <EMI ID = 144.1>

  
2,2-bis (4-hydroxyphenyl) propane. Most of the 2,2bis (4-hydroxyphenyl) propane crystallizes as an adduct with phenol in a molar ratio of 1: 1.

  
  <EMI ID = 145.1>

  
  <EMI ID = 146.1>

  
born below.

  
The washed crystals of the adduct are melted 1: 1

  
  <EMI ID = 147.1>

  
The main factor in the overall efficiency of the process lies in the recycling to the reactor feed of the by-products of the reaction, "" ie the compound of "Dianin", the isomers of bisphenol and triphenols, etc.

  
The Applicant has surprisingly found that a balance is thus maintained between the product and the by-products in the <EMI ID = 148.1>

  
reactor such that under steady-state recycle conditions the concentration of by-products in the reactor remains constant. Consequently, there is no further accumulation of by-products, and yields are obtained.

  
  <EMI ID = 149.1>

  
To more clearly describe the present invention for the smooth and continuous production of a high purity 2,2-bis (4-hydroxyphenyl) propane, a preferred variant is described below in detail with reference to FIG. 1, which is

  
  <EMI ID = 150.1>

  
and the series of operations suitable for carrying out the method of the invention.

  
Referring to Figure 1, the reactor charge in charge tank 11 is continuously prepared from: (1) make-up phenol from line 10; (2) supplemental acetone from line 46; (3) a recycled phenol-acetone mixture from line 46; and (4) a recycled mixture of phenol, reaction by-products and bisphenol A,

  
  <EMI ID = 151.1>

  
mix these four streams in proportions such that the composition of the feed admitted into the reactor is kept constant with regard to all the components entering into the process

  
and that the desired balance of concentrations be maintained

  
  <EMI ID = 152.1>

  
the reaction. the concentration of the latter is maintained

  
  <EMI ID = 153.1>

  
weight of the reactor feedstock. The molar ratio

  
  <EMI ID = 154.1>

  
The streams mixed to form the reactor charge pass continuously through line 12, through

  
  <EMI ID = 155.1>

  
The reaction chamber comprises a reactor 15 which advantageously consists of an enclosure of elongated shape provided with thermal insulation and temperature control means and a fixed bed.

  
  <EMI ID = 156.1>

  
above, and preferably a sulfonated crosslinked polystyrene resin which has about 20% of its available free acid groups esterified by a mercapto-ethanol promoter as described above. The catalyst resin is placed in the reactor in a manner which allows the flow of the reactor charge through the catalyst bed, and which also allows the appropriate contacting of the reactor charge with substantially all of the catalyst. and also avoids entrainment of the solid catalyst in the applied process stream which stream comes from the reactor.

  
The reactor charge, after passing through a preheated

  
  <EMI ID = 157.1>

  
via line 14, preferably at a flow rate such as to allow an average duration of contact of the reactants with the catalyst of one hour, at a temperature set at 75 [deg.] C, to give

  
  <EMI ID = 158.1>

  
compared to acetone. The effluent stream from the enclosure reacts

  
  <EMI ID = 159.1>

  
tion of recycled phenol wash liquor, from line 28, and the mixture is continuously sent through line 17 to an evaporation zone.

  
The evaporation zone, hereinafter referred to as "concentrator" 18, most advantageously consists of any industrial evaporator of the continuous film evaporator type with countercurrent vapor-liquid flow and preferably operating at reduced pressure. The evaporator feed line 17 admits phenol, unreacted acetone,

  
  <EMI ID = 160.1>

  
the pressure is at a sufficiently low level, for example 200 mm

  
  <EMI ID = 161.1>

  
reacted and water of reaction, the product obtained in the concentrator, by evaporation. We pass the product through the pipe
19 at a temperature preferably below 150 [deg.] C. We settle

  
  <EMI ID = 162.1>

  
completely removed from the concentrator product. In addition, a portion of the phenol is removed so that a concentration is

  
  <EMI ID = 163.1> <EMI ID = 164.1>

  
naked. The amount that preferably evaporates which meets the requirements is 20% by weight of the concentrator feed current.

  
  <EMI ID = 165.1>

  
advantageously of an oristallizer of the cooling type 20, provided with sufficient means to circulate the magma and

  
  <EMI ID = 166.1>

  
  <EMI ID = 167.1>

  
  <EMI ID = 168.1>

  
mother liquor. The resulting porridge passes. via line 21, in a liquid-solids separation zone.

  
The liquid-solids separation zone comprises a liquid-solids separator 22, advantageously a filtration apparatus, and preferably a centrifuge provided with accessory means for washing the crystals and for adjusting the temperature. The separation of the mother liquor from the

  
  <EMI ID = 169.1>

  
The crystals are washed, after separation from their mother liquor, with anhydrous phenol from line 25, the amount of washing liquid and the washing methods applied will depend.

  
  <EMI ID = 170.1>

  
A final separation of the crystals consisting only of the 1: 1 molar addition product of phenol and 2,2-bis (4-hydroxyphenyl) propane from the wash liquor in a filter and preferably in a centrifuge equipped with accessories for washing the crystals and adjusting the temperature. The mother liquor passes through line 23, and a portion of the washing liquor passes through line 26, then these liquids are combined and through line 27 are recycled to the tank 11 of the reactor feed. The mother liquor and wash liquor combined, used as recycling, consist of <EMI ID = 171.1>

  
this process.

  
The rest of the wash liquor circulates in the line
28 to be joined to the effluent stream from the reactor in the body line 16 and feed into the concentrator via the line 17.

  
  <EMI ID = 172.1>

  
solid-liquid separation zone through line 29 to be admitted into a melting zone 30 such as a stirred tank comprising temperature control devices and in which the lethal gold is melted, preferably at a temperature of

  
  <EMI ID = 173.1>

  
a phenol. The melt is admitted through line 31 into a final evaporation zone. In this final evaporation zone which, advantageously, comprises one or more industrial evaporators 32 of the pellioular evaporator type, the phenol is separated.

  
  <EMI ID = 174.1>

  
sufficiently low pressure (for example 5 mm Hg absolute) to ensure total evaporation of the pheno and its separation from the

  
  <EMI ID = 175.1>

  
through the pipe 33, in a cooling zone advantageously comprising a device 34 with a rotating drum for flaking, equipped with a temperature control device for solidification and flaking. The product is sent in the form of flakes to the packaging station.

  
  <EMI ID = 176.1>

  
line 36 to be joined to the anhydrous phenol which is admitted into the process through line 24 and coming from an external source.

  
The distillate from the concentrator 18 consisting of a certain quantity of phenol, unreacted acetone and water of reaction, passes through line 37 to a distillation zone to recover mainly the acetone and the phenolbydree in view.

  
  <EMI ID = 177.1>

  
38 and 41 each comprising a diatillation section, a rectifying seotion and a heater, and each provided with a means for adjusting the temperature and the reflux rate. The distillate from the oonoentrator enters column 38 at

  
  <EMI ID = 178.1>

  
and water from the column feed, and a substantially anhydrous mixture of phenol and acetone is obtained at the bottom of the column, which mixture is returned through line 39 to the reactor feed tank 11. in the form of a recycle stream. We set the composition of. distillate by adjusting the temperature at the top of the column. This distillate, containing only acetone and water, leaves column 38 through line 40 and enters a second column 41 in which acetone and water are separated (the water leaving the column in the form of of residue via line 42 and anhydrous acetone leaving the column as distillate via line 43). A portion of the anhydrous acetone is combined from

  
  <EMI ID = 179.1>

  
from column 38 in line 45 for recycling to reactor feed tank 11 via line 46. The remainder of the dry acetone from column 41 returns to the bottom of column 38 via line 44 to be used again in this column. The columns preferably work at atmospheric pressure.

  
  <EMI ID = 180.1>

  
recycling amount to increase the concentration and ultimately this seriously impairs process efficiency or requires expensive disposal steps. But, since the promoters in the present process are attached to the polymer catalyst,

  
  <EMI ID = 181.1>

  
of the reaction, and therefore, none is in the free state in the reaction zone, or in the apparatus serving

  
during the implementation of the process or in the product 2,2-bis (4-hydro-

  
  <EMI ID = 182.1>

  
costly purification procedures.

  
  <EMI ID = 183.1> phenyl) propane of high purity according to the invention emerges clearly from the following examples given by way of illustration of this process.

Example 22

  
  <EMI ID = 184.1>

  
from the recycle mother liquor and wash liquor from the solids-liquid separator; anhydrous phenolacetone mixture of recycling from the dehydration columns, and additional phenol and acetone. The load has the following composition:

  

  <EMI ID = 185.1>


  
This load is admitted continuously at a controlled flow rate in

  
a reactor consisting of a stainless steel jacketed tube lined with 2 265 kg of sulfonated crosslinked polystyrene resin pre-

  
  <EMI ID = 186.1>

  
free acid groups with mercaptoethanol and then made anhydrous by the methods given above. We circulate

  
  <EMI ID = 187.1>

  
the reactor jacket and a charge heater. The feed is admitted into the reactor at a controlled flow rate sufficient to have a contact time of the reactants with the catalyst, of one hour.

  
The current leaving the reactor is passed through the concentrate.

  
  <EMI ID = 188.1>

  
equipped with a condenser and a tank. The reactor output stream has the following composition:

  

  <EMI ID = 189.1>


  
  <EMI ID = 190.1>

  
Concentrating the effluent stream from the soue reactor

  
  <EMI ID = 191.1>

  
140 [deg.] C. 20% by weight of the feed is removed in the form of a distillate which has the following composition:

  

  <EMI ID = 192.1>


  
  <EMI ID = 193.1>

  

  <EMI ID = 194.1>


  
  <EMI ID = 195.1>

  
  <EMI ID = 196.1> and the centrifuge cake is exhausted of all liquor. The wash liquor is collected in the same container as the above separate mother liquor. The combined filtrate separated from the centrifuge cake has the following composition:

  

  <EMI ID = 197.1>


  
This filtrate is recycled to the reactor.

  
The intermittently washed cake is removed from the perforated basket of the centrifuge, it has the following composition:

  

  <EMI ID = 198.1>


  
The cake is heated to a temperature of 130 ° C. in a tank stirred and jacketed to melt the crystals of the adduct. The molten material then passes through a vacuum evaporator in which the phenol is evaporated.

  
and separated from the product under a reduced pressure of 1.0 mm Hg absolute at a temperature of 200 [deg.] C. The molten product is cooled

  
from the evaporator to crystallize the product which is sprayed. The product has the following composition:

  

  <EMI ID = 199.1>


  
  <EMI ID = 200.1>

  
in the dehydration column and is dehydrated by adding

  
  <EMI ID = 201.1>

  
  <EMI ID = 202.1> <EMI ID = 203.1> a second dehydration column in which it is fractionated to obtain practically anhydrous acetone containing

  
  <EMI ID = 204.1>

  
column. We get rid of the water. The phenol content of the water is below one part per million.

  
The residue from the first column and recycled to the feed has the following composition:

  

  <EMI ID = 205.1>

Example 23

  
97.9 kg of the reactor feed is prepared

  
from: recycle mother liquor and a portion of liquor

  
recycle wash from the solid-liquid separator; recycled and anhydrous mixture of phenol-acetone from the dehydration columns and additional phenol and acetone. The load has the following composition:

  

  <EMI ID = 206.1>


  
This charge is continuously admitted at a regulated flow rate, in the

  
  <EMI ID = 207.1>

  
as described in Example 22.

  
The effluent stream from the reactor has the following composition
  <EMI ID = 208.1>
 Conversion with respect to the acetone consumed = 50%.

  
10.9 kg of recycle wash liquor from the solids-liquid separator is added to the 97.9 kg of reactor effluent. The composition of the mixture is as follows:

  

  <EMI ID = 209.1>


  
  <EMI ID = 210.1>

  
in a jacketed, glass-lined autoclave with condenser and reservoir, and the mixture is concentrated therein under pressure

  
  <EMI ID = 211.1>

  
  <EMI ID = 212.1>

  
following tion:

  

  <EMI ID = 213.1>


  
The concentrate has the following composition:

  

  <EMI ID = 214.1>


  
The latter is cooled with stirring in a crystallization apparatus consisting of a jacketed autoclave lined with

  
  <EMI ID = 215.1>

  
  <EMI ID = 216.1>

  
The slurry of crystals and mother liquor is charged continuously in a centrifuge maintained at 40-45 [deg.] C. The separated mother liquor is returned to the reactor feed as a recycle stream having the following composition:

  

  <EMI ID = 217.1>
 

  
  <EMI ID = 218.1>

  
the mother liquor adhering thereto, in a stainless steel jacketed autoolave fitted with stirring devices and containing a

  
  <EMI ID = 219.1>

  
separate the collected phenol wash. Then

  
the cake is spray washed with 1/5 of its weight of phenol

  
  <EMI ID = 220.1>

  
of any washing liquor. This wash liquor is collected in the same container as the wash liquor separated from the slurry. The combined filtrate separated from the cake of the centrifuge has the following composition:

  

  <EMI ID = 221.1>

This filtrate is recycled to the reactor effluent stream.

  
The cake is intermittently removed from the perforated basket

  
the centrifuge; this cake has the following composition:

  
  <EMI ID = 222.1>

  

  <EMI ID = 223.1>


  
The cake in the centrifuge is heated to 130 ° C. and the melt is charged to a vacuum evaporator in which the phenol is evaporated and the residue is cooled to crystallize as described in example 22.

  
The product has the following composition:

  

  <EMI ID = 224.1>
 

  
The distillate from the concentrator is passed through

  
  <EMI ID = 225.1>

  
  <EMI ID = 226.1>

  
tion, in steady state, of the by-product @ of the reaction of acetone and phenol, in the reaction area of the process oon-

  
  <EMI ID = 227.1>

  
  <EMI ID = 228.1>

  
outside the reaction zone a transposition of at least part of the reaction by-products of acetone and phenol

  
  <EMI ID = 229.1>

  
both from the reaction zone, separating substantially all of the condensation water and unreacted acetone therefrom; that the concentrated mixture thus obtained is dressed in a transfer zone

  
  <EMI ID = 230.1>

  
practically insoluble and saturated with phenolic solvent; the reaction by-products of the ao-

  
  <EMI ID = 231.1>

  
and returning the outgoing mixture, enriched in product, to the reaction zone, with a further quantity of phenol and acetone. The load supplying the transposition zone has preferably

  
  <EMI ID = 232.1>

  
propane, as an equimolar adduct with phenol.

  
Surprisingly, the fact of introducing a transposition stage outside the reaction zone allows a significant decrease in the concentration of the by-products, in the steady state, although a prolonged contact of the reactants in the zone.

  
  <EMI ID = 233.1>

  
also produces a transposition, does not bring such a reduction. Applicants do not wish to be bound by any definite theoretical explanation, but it is believed that the superior results of the process of the present invention are to be attributed to the fact that the rearrangement reaction is carried out in the substantially complete absence of 'water. The presence of even small amounts of water, that is to say greater than about 1.5% by weight of the mixture containing the by-products, prevents complete- <EMI ID = 234.1>

  
propane. Therefore, in the condensation reaction of phenol and acetone in which water is formed in quantity

  
  <EMI ID = 235.1>

  
prolonged reactions do not give a significant decrease in the concentration of by-products, because the rate of transposition

  
  <EMI ID = 236.1>

  
reaction zone by the cation exchange resin acting as a catalyst, reaches a negligible value long before the concentration at theoretical equilibrium has been obtained.

  
The volume and dimensions of the condensation and transposition reaction zones are not critical, provided sufficient contact of the respective mixtures with the cation exchange resin is obtained. Areas which may be suitable are, for example, those of enlarged cross-section, such as a chamber, tank, autoclave, etc., and those of restricted cross-sections, such as tubular vessels and serpentines, etc. In the context of the present invention, it is possible to use several reaction or transposition zones connected in series or in parallel. They should be provided with devices for maintaining or regulating the temperature in the respective zones and devices for preventing the entrainment of the catalyst in the products leaving them.

  
Condensation reaction - The residence time of acetone and phenol in the reaction zone can be varied to a considerable extent. It depends mainly on the particular molar ratio between reactants, the quantity and the exchange capacity of the cation exchange catalyst which is used, the temperatures at which one operates, the desired percentage of transformation, and other similar factors. The minimum residence time in the reaction zone is the time sufficient to start the reaction and the maximum residence time is that which is sufficient for a substantially complete reaction between the reactants present. Usually at least 5% of the acetone reacts and preferably no more than 95%, counted as molecules.

   It is preferred that the minimum conversion of acetone is
20% and the maximum of 80%. A conversion of about 50% is particularly preferred, because as the percentage of conversion increases the reaction rate decreases and the process becomes less economical, if one examines the amount of product per unit time. No fixed residence time is critical in the present invention with respect to yield, the same extremely high yields being obtained with relatively short contact times and low conversion rates as the high yields achieved with times of conversion. prolonged contact and high rates of transformation. Contact times as short as one hour and a conversion rate of about 50% are the most advantageous, as they give

  
  <EMI ID = 237.1>

  
  <EMI ID = 238.1>

  
phenyl) -propane.

  
  <EMI ID = 239.1>

  
  <EMI ID = 240.1>

  
with dimethyl ketone.

  
The reaction of acetone and phenol is preferably carried out with an amount of phenol greater than the stoichiometric amount, that is to say more than 2 moles of phenol per mole of acetone present in the reaction zone, and preferably between 3

  
and about 20 moles of phenol per mole of acetone. The reports on

  
  <EMI ID = 241.1>

  
are useful when the temperature of the reaction zone is relatively low, as this prevents plugging of the reaction zone by solidified reaction products or by addition products of the phenol crystallized with reaction products. Particular preference is given to

  
  <EMI ID = 242.1>

  
or 10: 1.

  
It is essential, to maintain high rates of training

  
  <EMI ID = 243.1>

  
of water, because the overall yield of the process of the invention depends <EMI ID = 244.1>

  
the presence of less than 2.0% of water in the reaction zone for the catalysis with the cation exchange resins :; is done under optimal conditions.

  
In the reaction zone, the temperature should be such as to maintain the reactants in the liquid phase. In general,

  
  <EMI ID = 245.1>

  
the lower the temperature at which one operates in the reaction zone, so as to avoid blocking the column with solidified 2.2-bis- (4-hydroxyphenyl) -propane or with its crystallized product of addition with phenol. The use of temperatures which are so high that they cause

  
  <EMI ID = 246.1>

  
or cation exchange resin, or which they determine

  
an exaggerated rate of by-product formation should be avoided. The particular temperature used in the reaction zone can be varied between about 30 [deg.] And 125 [deg.] C depending on other operating conditions in the reaction zone, such as, for example, percent conversion per pass, residence time or length of contact time between catalyst and reactants, pressure, etc. In order to avoid the blockage of the reaction zone by solidified reaction products, oe which

  
  <EMI ID = 247.1>

  
  <EMI ID = 248.1>

  
tion at atmospheric pressure, or at a lower pressure

  
  <EMI ID = 249.1>

  
  <EMI ID = 250.1>

  
it is preferred to adopt atmospheric pressure or a slightly elevated pressure, in order to ensure, in continuous operation, a suitable circulation of materials in the device.

  
  <EMI ID = 251.1>

  
no transposition, of the mixture coming from the reaction sone, called "tributary mixture" can vary to a considerable extent

  
and this duration depends mainly on the extent of the conversion desired, the temperatures adopted, and the exchange capacity of the cation exchange catalyst which is used. The minimum residence time is the time sufficient to start the transposition reaction and the maximum residence time is that sufficient for practically complete transposition.

  
products due to the reaction in 2,2-bis- (4-hydroxyphenyl) -propane, i.e. to allow equilibrium to be established.

  
To carry out the conversion characterizing the process of the present invention, the effluent mixture is first freed of substantially all of the unreacted acetone and of the condensation water. At this point, the tributary mixture comprises: phenol; the reaction product of acetone and phenol, namely 2,2-bis- (4-hydroxyphenyl) -propane; and a variety of acetone and phenol reaction byproducts, for example 4-p-hydroxyphenyl-2,2,4-trimethylchromane
(compound of Dianin), triphenols and 2,4-dihydroxy-2,2-diphenyl-propane, which are generally referred to herein as "reaction products of acetone and phenol". The 2,4 isomer is the predominant by-product of the acetone reaction and

  
phenol.

  
It is essential, to achieve the transposition of these reaction by-products into 2,2-bis- (4-hydroxyphenyl) -propane, that

  
the transposition sone is essentially anhydrous, ie it contains at least 1.5% by weight of water relative to the weight of the effluent mixture entering the transposition zone. As indicated above, a higher water content

  
  <EMI ID = 252.1>

  
happy that the medium is anhydrous, that is to say that there is less

  
  <EMI ID = 253.1>

  
better transposition rates.

  
  <EMI ID = 254.1> erasures, the equilibrium proportion is the lowest, but

  
the speed of transposition is the least. It is therefore desirable to find a compromise between the rate of transposition and the concentration of byproducts at equilibrium, by operating with temperatures of the transposition zone compound.

  
  <EMI ID = 255.1>

  
for the transposition zone having the dimensions described in the examples and with the catalyst used, is that which is preferred in order to obtain the optimal rates and concentration at equilibrium. It is advisable to provide a series of transposition zones heated to progressively decreasing temperatures, in such a way that an initial transposition is carried out.

  
  <EMI ID = 256.1>

  
the in equilibrium.

  
The transposition zone can be maintained at atmospheric pressure or at a lower or higher pressure

  
to that of the atmosphere. It is also possible to operate in an atmosphere

  
inert gas. It is generally preferred to operate at atmospheric pressure or at a slightly elevated pressure, in order to ensure, in continuous operation, a suitable circulation of the materials in the

  
the device.

  
The Applicant uses cation exchange resins as solid catalysts in the condensation and conversion stages of the continuous process of the present invention. These resins are insoluble in the reaction mixture and in the effluent mixture, whereby the problem of separating the catalyst from the effluent from the condensation reaction zone or from the transposition zone and the separation of the catalyst is avoided. removal of small amounts of catalyst from the product. During all of the condensation and conversion stages and the isolation stages, the catalyst remains in the reaction or conversion zone and does not appear elsewhere in the equipment used in the process. Its service life in the present process is indefinitely long. Cation exchange resins should not

  
not necessarily require regeneration, if care is taken to avoid introducing basic metal ions, such as sodium, potassium, calcium, etc., or other impurities which deactivate the cation exchange groups of the resin. The use of the insoluble catalyst further gives the advantages.

  
  <EMI ID = 257.1>

  
resistant to acid corrosion, devices which would be

  
  <EMI ID = 258.1>

  
neutralization which are common to other processes.

  
The ion exchange resins useful in the present process are substantially insoluble polymeric backbones to which cationic exchange groups are chemically bonded. The exchange potential of the attached acid groups and the

  
  <EMI ID = 259.1>

  
reaction mixture of phenol and acetone or with the effluent mixture, determines the catalytic efficiency of a determined ion exchange resin. Thus, although the number of acid groups bonded to the polymer backbone of the resin determines the theoretical "exchange capacity" of this resin, a more exact criterion of catalytic efficiency is the number of acid groups available to contact. with reagents. This contact can occur on surfaces, both interior and exterior,

  
  <EMI ID = 260.1>

  
ne which offers maximum contact area, for example microspheres or porous beads or grains, is highly desirable

  
and it provides the highest transformation and rearrangement reaction rates and the maximum economy in this process. However, the special form of the ion exchange resin used is not critical.

  
The ion exchange resins should be substantially insoluble in the reaction mixture and in any solvent to which

  
  <EMI ID = 261.1>

  
The resin is generally due to a high degree of cross-linking within the resin, but this insolubility may be due to other factors, for example, a high molecular weight or a high degree of crystallinity.

  
In general, the higher the exchange capacity of a resin, that is, the greater the number of milliequivalents of acid per gram of resin, and the more advantageous the resin is for use in the present process. We prefer them <EMI ID = 262.1>

  
about acid value per gram of dry resin. Particular preference is given to resins bearing, as linked group, cationic exchange groups, of acids having a high exchange potential. Lee result @ obtained with grouped

  
  <EMI ID = 263.1>

  
sulfonic acid, etc. Most of these resins and many others can be purchased commercially under marked

  
  <EMI ID = 264.1>

  
Many ion exchange resins in sodium or other salt form are received from the manufacturer and must be converted to hydrogen or acid form prior to use in the present process. The conversion can easily be accomplished by washing the resin with a solution of a suitable acid. For example, a sulfonated resin should be washed with a sulfuric acid solution. Salts formed during processing are conveniently removed by washing the resin with water or with a solvent for the salt.

  
It occurs frequently, as a result of the washing operation described above, either from the manner in which the manufacturer

  
  <EMI ID = 265.1>

  
own weight of water. Substantially all this water, that is to say

  
all but about 2%, at most, must be removed before using the ion exchange resin as a catalyst for the condensation reaction in the present process, and all

  
  <EMI ID = 266.1>

  
ion exchange sine as a catalyst for the transposition reaction. Methods which may be suitable for removing water from the resin include: drying the resin under reduced pressure in an oven; resin digestion <EMI ID = 267.1>

  
dane liquid anhydrous phenol as the solvent, for a time sufficient to fill the resin interstices with phenol and azeotropic distillation of water and phenol in advance of excess phenol.

  
When the resin has been prepared in this way, to be sure that it is still anhydrous, he

  
  <EMI ID = 268.1>

  
that while it is being used in the process. Alternatively, the catalyst can be prepared after placing it in the treatment plant, simply by circulating the reaction mixture through the catalyst until substantially all of the water has been removed. In this last way of operating, the conditioning is effected at the liver by acetone

  
and by phenol.

  
  <EMI ID = 269.1>

  
sor for the condensation reaction as for the transposition reaction. By these terms is meant an ion exchange resin which is substantially completely filled or saturated with a phenolic solvent, that is to say with monohydroxy-aromatic compounds such as the phenol proper, the cresols and the xylenols. Of course, to avoid cross reactions which decrease

  
yield, it is advantageous to use the phenol itself as a phenolic solvent. Saturation with a phenolic solvent activates the catalyst for use in the present process and also prevents absorption of moisture.

  
We have found that the catalytic efficiency of the ion exchange resins described above, both in the condensation reaction and in the rearrangement reaction, is increased appreciably when the resin is treated with a mercapto. alcohol before using it in the

  
the present invention. The presence of free promoters of the condensation of phenol and acetone, such as alkyl-mercaptans and mercapto-acids, in the reaction zone with the ion exchange resins, although it increases the reaction rate, results in sulfur contamination of,

  
  <EMI ID = 270.1> <EMI ID = 271.1>

  
mineral acids with equivalent promoters. Contamination is manifested by a strong smell of sulfur and one cannot

  
not eliminate it, even by successive recrystallizations

  
of the product. Thus the advantage of a markedly accelerated reaction rate is neutralized by additional contamination of the product.

  
One can get all the advantages of a facilitated reaction

  
  <EMI ID = 272.1>

  
to the polymer backbone of the resin. The use of this activated catalyst is preferred in the present invention, due to the fact that the condensation and transposition reactions are faster and due to the lack of odor or other contamination, by sulfur, of the product, 2,2-bis- (4-hydroxyphenyl) -propane, made with the ion exchange resin thus modified. The manufacture of these catalysts consisting of partially esterified ion exchange resins is described.

  
above. Surprisingly, partial esterification does not determine a decrease in catalytic activity although

  
  <EMI ID = 273.1>

  
cations, are blocked.

  
Remarkable yields and savings, per kilogram of catalyst, have been made possible by the use of solid ion exchange resins. Experimental tests have shown that the resins remain catalytically effective for an indefinite period of time. 300 kg of 2,2-bis- (4-hydroxy-phenyl) -propane were made per kg of resin, with no signs of weakening of the catalytic efficiency. Thus, thanks to the resins described above, it is possible to operate a process automatically

  
and continuously without any regeneration problems

  
catalyst.

  
To initiate the reaction, phenol and acetone, both substantially anhydrous, are heated to reaction temperature. that is to say containing at most less than 2.0% water by weight and preferably anhydrous, that is to say containing less than 0.2% water, and are passed through a fixed porous bed of ion exchange resin, preferably from top to bottom, under slight pressure, so as to maintain sufficient flow through

  
of the bed, although gravity flow through the column also gives satisfactory results.

  
The mixture leaving the catalyst bed is sent to

  
a concentrator, which can be any conventional evaporator of the film type. preferably an evaporator in which the vapors and liquids circulate in a center current and in which all the water and all the acetone and part of the phenol come out

  
as head products.

  
Depending on the temperature of the mixture leaving the reactor and depending on the pressure prevailing in the concentrator, it is possible to heat

  
or cooling the reaction mixture so as to vaporize all of the water of reaction, and the unreacted acetone. These vapors come out at the top, (with some phenol vapors if necessary), leaving as residues or tails the 2,2-bis-
(4-hydroxyphenyl) -propane, phenol and reaction by-products of acetone and phenol. The temperature of this concentration should not be so high as to cause decomposition of 2,2-bis- (4-hydroxyphenyl) -propane and it is

  
preferably between 100 [deg.] and 150 [deg.] C approximately, the pressure

  
of operation being adjusted in such a way that substantially complete vaporization of the acetone and water is obtained, and

  
leaving in the residue at least one mole of phenol per mole

  
2,2-bis- (4-hydroxyphenyl) -propane and preferably 4 to 10 moles of phenol, together with substantially all of the by-products and 2,2-bis- (4-hydroxyphenyl) -propane .

  
The overhead product, comprising acetone, water and phenol, is passed from the concentrator to a dehydration zone for the purpose of removing water, leaving the acetone and phenol which are recycled back to the concentrator. treatment. This dehydration can be carried out by contacting the mixture of acetone, water

  
and phenol with an ascending stream of anhydrous acetone vapor. This avoids adding another component to the reaction process.

  
  <EMI ID = 274.1> In this way of operating, the mixture is introduced into the side of the column and anhydrous acetone at the lower part of the column, which is maintained at a temperature between 155 [deg.] And
165 [deg.] C at atmospheric pressure. The acetone rises in the column on contact with the feed and the water is removed in very good yield. The moisture-laden acetone vapors exit through the top of the column, which is maintained at a temperature of about 58 [deg.] C, when working at atmospheric pressure, by adjusting the reflux ratio. It is necessary to regulate the temperature at the top of the column, to be sure that a distillate of acetone and water, free of phenol, passes into the second column, from which the water is removed by distillation. fractional.

   The anhydrous acetone recovered is recycled.

  
The bottoms of the first column, constituted by anhydrous phenol and acetone, are recycled in the treatment.

  
The water leaving as bottoms of the second column can be discarded without requiring further purification to separate the phenol or other organic substance therefrom.

  
Any other separation technique can also be used which removes water from the concentrator heads.

  
In one embodiment of the present invention, the bottoms are sent directly to a crystallization zone.

  
  <EMI ID = 275.1>

  
pane, phenol and by-products.

  
The crystallization is carried out by cooling the tails

  
  <EMI ID = 276.1>

  
  <EMI ID = 277.1>

  
crystallization varies depending on the conditions under which the concentrator operates. By distilling off more or less phenol, the molar ratio of phenol to product can be adjusted in the feed to the crystallization area. Phenol in an amount greater than one mole per mole of 2,2-bis- (4hydroxyphenyl) -propane takes the by-products, all of which are

  
  <EMI ID = 278.1>

  
  <EMI ID = 279.1>

  
  <EMI ID = 280.1>

  
  <EMI ID = 281.1>

  
The crystals are separated from the mother liquor by centrifugation, filtration or any other suitable method and washed, preferably with a further quantity of phenol or a mixture of phenol and acetone to remove traces of liquor. -mother. The washing liquids and the mother liquor, which at this time consist of phenol, by-products and a little 2,2-bis- (4-hydroxyphenyl) -propane, are sent to the transposition zone.

  
The crystals, washed, of the 1: 1 adduct of phenol and 2,2-bis- (4-hydroxyphenyl) -propane are melted and charged to a second evaporation zone in which the phenol is separated. 2,2-bis- (4-hydroxyphenyl) -propane and recycled to the treatment, leaving as residue 2,2-bis- (4-hydroxyphenyl) propane. The 2,2-bis- (4-hydroxyphenyl) -propane obtained as a product does not contain any trace of catalyst or promoter. Make them

  
  <EMI ID = 282.1>

  
  <EMI ID = 283.1>

  
introduced into the transposition reactor and it is advantageous for them to pass there under a slight positive pressure. The transposition of the reaction by-products into 2,2-bie- (4-hydroxyphenyl) -propane takes place and the effluent from the transposition zone, now enriched in 2,2-bie- (4-hydroxyphenyl) -propane, is recycled to the reaction zone.

  
In a variant, the transposition zone may be placed after the concentration zone and before the crystal zone.

  
  <EMI ID = 284.1>

  
nation and transposition described above. The other stages of treatment remain the same.

  
In order to more fully set out the nature of the present invention for the continuous, continuously repeated production of a

  
  <EMI ID = 285.1>

  
referring to Figure 2, in which is illustrated a cast of apparatus and series of processing stages, suitable for implementing <EMI ID = 286.1>

  
implements the process of this invention.

  
Referring to this Figure 2, the reactor charge is prepared continuously in a feed tank 11 with:
1 [deg.] Make-up phenol from line 10; 2 [deg.] Acetone

  
  <EMI ID = 287.1>

  
and 4 [deg.] The recycled and transposed mixture of the reaction. phenol and acetone, composed of phenol, reaction byproducts and bis-phenol, from line 48. These four streams are mixed in proportions such as the composition of the feedstock of the reactor remains constant from the point of view of all the components entering into the treatment.

  
Below is a comparison of typical material balances at this stage of the process, with and without transposition:

  

  <EMI ID = 288.1>


  
Note that the concentration in percent by weight

  
  <EMI ID = 289.1>

  
under steady-state conditions, in the reactor feedstock.

  
The mixed streams forming the feedstock of the reactor pass continuously through a conduit 12, through a preheater
13, in which they are heated to about 70-75 [deg.] C, before entering the reaction zone.

  
The reaction zone comprises a reactor 15 which is advantageously an elongated chamber, provided with devices for

  
  <EMI ID = 290.1> <EMI ID = 291.1>

  
available free acid groups were esterified with mer-

  
captoethanol as a promoter, as described above.

  
The catalyst resin is placed in the reactor 15 in a manner permitting the flow of the feed fed to the reactor through the catalyst bed and also ensuring a proper flow of the feed to the reactor and substantially all of the catalyst and also preventing entrainment of the solid catalyst by flowing out of the reactor chamber to the rest of the process equipment.

  
  <EMI ID = 292.1>

  
their 13, enters continuously through the end of the reactor 15 through line 14, with a flow rate such that it gives an average residence time of the reactants with the catalyst of approximately one hour to one hour.

  
  <EMI ID = 293.1>

  
compared to acetone. The mixture leaving the reaction chamber enters the line 16 and it is mixed with a part of the recycled phenolic wash liquor arriving through the line 28 and the mixture continuously flows through the line 17 into the evaporation area.

  
Below is a comparison of typical material balances, at this

  
  <EMI ID = 294.1>

  
ment with transposition:

  

  <EMI ID = 295.1>


  
It should be noted that at this stage of the reaction, the concentration by weight of the by-products is considerably reduced (5.1% against 8.6%).

  
The evaporation zone referred to herein as the concentrate

  
  <EMI ID = 296.1>

  
industrial film type, with countercurrent flow of vapors and liquids, and preferably operating under reduced pressure. The feedstock of the evaporator, arriving via line 17, consisting of phenol, unreacted acetone, water of condensation, 2,2-bis- (4-hydroxyphenyl) -propane and reaction by-products of phenol and <EMI ID = 297.1>

  
  <EMI ID = 298.1>

  
absolute mercury, to allow elimination, by evaporation,

  
unreacted acetone and thus whistled water from the product

  
  <EMI ID = 299.1>

  
  <EMI ID = 300.1>

  
maintains a constant concentration of components in the concentrator product. The preferred amount of product evaporated, which

  
  <EMI ID = 301.1>

  
load entering the concentrator.

  
  <EMI ID = 302.1>

  
by-products of the reaction of phenol and acetone, pass continuously through line 19 into the crystallization zone, preferably constituted by a crystallizer of the cooling type
20, provided with a device sufficient to circulate the magma and a device for removing heat and regulating the temperature.

  
In an alternative embodiment, it is interposed in

  
  <EMI ID = 303.1>

  
phenolic solvent, such as Dore: 50-X-4, which has preferably been partially esterified with a promoter mercapto-alcohol,

  
as described above. The transposition reaction,

  
in reactor 47 '. is the same as that which occurs

  
in reactor 47 of the preferred embodiment.

  
Cooling the mass to a temperature preferably equal to about 40 [deg.] C, with the agitation indicated above, in the crystallization zone, gives a liquid slurry of crystals consisting solely of the adduct of a mole of phenol per mole of 2,2-bis- (4-hydroxyphenyl) -propane in its mother liquor. The resulting liquid slurry is passed through line 21 into a zone for separating solids and liquid.

  
The solids and liquid separation area includes

  
a separator 22 of solids and liquids, advantageously a filtration apparatus and preferably a centrifugal machine provided with accessories for washing the crystals and a device for adjusting the temperature. The separation of the mother liquor and the crystals is carried out, preferably at a temperature of
4000 approximately.

  
After separating the crystals from their mother liquor, they are washed with anhydrous phenol coming through line 25, the amount of washing phenol and the specific washing techniques adopted depending on the purity desired. give to the final product. A final separation of the crystals, consisting only of the adduct of one mole of phenol per mole of

  
  <EMI ID = 304.1>

  
carried out advantageously in a filtration apparatus and preferably in a centrifugal machine provided with accessory devices for washing the crystals and a device for adjusting the temperature. The mother liquor passes through line 23 and part of the washing liquor passes through line 26, then

  
the

  
they are mixed and returned by / leads 27 finally in

  
the feed tank 11 as a recycling product. The mixture of mother liquor and wash liquor to be used as a product

  
recycling and which consists of phenol, by-products of the reaction of acetone and phenol and 2,2-bis- (4-hydroxyphenyl) -propane, passes into the transposition zone 47 via the conduit 27, if it has not previously been transposed into the transposition reactor 47 'or if the two transposition zones are used.

  
Below is a comparison between typical material balances, at this stage of the process, between treatment without transposition and treatment with transposition:

  

  <EMI ID = 305.1>


  
It should be noted that at this stage the weight percent concentration of the by-products is again significantly lowered (6.6% vs. 11.2%).

  
The purity of the crude product, i.e. the adduct of one mole of 2,2-bis- (4-hydroxyphenyl) -propane to one mole of phenol, in a non-rearranging process, is determined. general of
About 62%. The addition of the transposition typically improves the purity of the product to 73.6%. This allows more easily -! A more efficient purification and with a better yield and a greater productivity in purer product.

  
The mixture entering the transposition reactor 47, arriving via the line 27, comes into contact with the catalyst consisting of a cation exchange resin saturated with phenolic solvent, and which has preferably been esterified with a mercaptoalcohol. The resin is placed in the form of a porous bed in the reactor, which is suitably an elongated chamber provided with devices for temperature control. In the transposition reactor 47, part of the by-products of the reaction of phenol and acetone reacts again, i.e. undergoes a

  
  <EMI ID = 306.1>

  
propane.

  
The effluent from the transposition reactor is then passed through.

  
  <EMI ID = 307.1>

  
this stage:

  

  <EMI ID = 308.1>


  
The remainder of the wash liquor from the solids and liquid separator 22 exits through line 28 to mix.

  
to the current leaving the reactor in line 16, to form the feed supplying the concentrator via line 1 ?.

  
The washed crystals of 1: 1 molar adduct of phenol and 2,2-bis- (4-hydroxyphenyl) -propane are discharged from the

  
zone for separating solids and liquid through a conduit 29 to a melting zone, suitably a melter 30 such as a stirred tank provided with a temperature control device, in which the crystals are melted at a temperature of 130 [deg.] C approximately, to a melt of 2,2-bis- (4-hydroxyphenyl) -propane in phenol. This melt is sent through line 31 to a final evaporation zone. In the final evaporation zone, which suitably comprises one or more industrial evaporators 32, of the film type, the phenol is separated by evaporation of the 2,2-bie-.
(4-hydroxyphenyl) -propane constituting the product, preferably

  
under a sufficiently low pressure (eg 5 mm absolute mercury), to ensure complete evaporation of the phenol and separate it from the evaporator product, at a temperature not exceeding 200 [deg.] C.

  
The product of the evaporator, consisting of a molten stream

  
  <EMI ID = 309.1>

  
through line 33 into a cooling zone, suitably a rotating drum scaler.

  
The distillate from the final evaporation passes through the pipe
36 to be mixed with anhydrous phenol which enters the treatment from an external source through line 24.

  
  <EMI ID = 310.1> phenol, in unreacted acetone and in the water of the reaction, is sent through line 37 to a distillation zone, in order to recover essentially anhydrous acetone and phenol, for recycle them. The distillation zone can be made up

  
two columns 38 and 41 each consisting of a draw-off section, a rectification section and a reboiler and provided with an adjustment of the temperature and of the reflux ratio. The distilla from the concentrator enters roughly in the middle of the column
38; anhydrous acetone enters the column through the reboiler via line 44. Acetone and water are separated from the feed in the column and a substantially anhydrous mixture of phenol and acetone is obtained at the bottom of the column. , which is returned through line 39 to the reactor feed tank 11,

  
  <EMI ID = 311.1>

  
both of column 38, adjusting the temperature at the top of the column. This distillate, consisting only of acetone and water, leaves column 38 through line 40 and enters a second column 41 in which acetone and water are separated.
- the water leaving the column in the form of tails through the pipe
42 and the anhydrous acetone leaving the column as a distillate via line 43. Part of the acetone coming from column 41 is mixed with the anhydrous mixture of phenol and acetone coming from column 38 via line 45, to be recycled via line 46 to the reactor supply tank 11. The rest of the anhydrous acetone coming from column 41 is returned to the bottom of column 38 through line 44 to be reused in this column.

   The columns preferably operate at a pressure close to atmospheric pressure.

  
the following examples are intended to illustrate the practice of the invention and they should not be considered

  
  <EMI ID = 312.1>

  
award-winning ** by weight.

Example 24

  
A typical effluent mixture is passed, intended to be recycled to the reaction zone in the process described above and comprising:

  

  <EMI ID = 313.1>


  
in a tubular transposition reaction vessel, 1.83 m long and 102 mm internal diameter, lined with

  
  <EMI ID = 314.1>

  
cations (oopolymer of sulfonated styrene and 4% divinylbenzene, sold by the Dow Chemical Company as

  
  <EMI ID = 315.1>

  
with mercapto-ethanol. as indicated above, then saturated with phenolic solvent for the

  
make anhydrous by immersion in molten anhydrous phenol. The amount of catalyst used is 4.0 milliequivalents of H + per gram of dry resin. The effluent mixture is preheated

  
  <EMI ID = 316.1>

  
Once the steady-state conditions have been reached, samples of the product leaving the transposition reactor are collected. The samples are freed from their phenol by heating them to 200 [deg.] C under the absolute pressure of 1 mm of mercury. The content of by-products of the residue is then determined by first extracting 2,2-bis- (4-hydroxy-) with carbon tetrachloride.

  
  <EMI ID = 317.1>

  
then measuring the absorption of light by the byproduct solution and comparing it with a standard. The analysis is the same as that which is carried out on the effluent product which has not been transposed. The results of the analysis of the transposed effluent product will be found in Table I below. The results of the analysis of the effluent mixture which has not undergone any transposition have been reproduced for convenience.

BOARD

  

  <EMI ID = 318.1>


  
  <EMI ID = 319.1>

Example 25

  
We start again by operating as in Example 24 using

  
  <EMI ID = 320.1>

  
results of the transposition reaction are shown in Table II. The values obtained with the eohantillone which has not undergone transposition are given for comparison.

TABLE II

  

  <EMI ID = 321.1>

Example 26

  
The procedure of Example 24 is followed, but the product of the catalyzed condensation is used as effluent for transposing.

  
  <EMI ID = 322.1>

  
for the transposition is again the catalyst of the example

  
24. A marked transposition of the reaction by-products to 2,2-bis- (4-hydroxyphenyl) -propane is obtained.

  
This example illustrates the wide possibility of application of

  
  <EMI ID = 323.1>

  
  <EMI ID = 324.1>

  
used for condensation.


    

Claims (1)

ABSTRACT A- Process for producing biephenol by reaction of <EMI ID = 325.1> or in combinations 1. A phenol having a reactive hydrogen atom in para to the phenolic hydroxyl group is reacted with a ketone having at least one methyl group in alpha to the carbonyl, the amount of phenol present being greater than the etoichiometric ratio, in carrying out the reaction in the presence of a cation-exchangeable polymeric resin which is practically insoluble. <EMI ID = 326.1> 2. Phenol is reacted with acetone. 3. The polymeric cation exchange resin contains virtually no water. 4. This resin contains strong acid groups. <EMI ID = 327.1> 6. The resin is sulfonated styrene-divinylbenzene, sulfonated polymer of cross-linked styrene, phenol-formaldehyde-aulfonic acid resin, or benzene-formaldehyde-sulfonic acid resin. 7. At least two moles of phenol are used per mole. of ketone. 8. Between 3 and 20 moles of phenol are used per mole of ketone. 9. A temperature between 40 and 100 [deg.] C is applied. 10. An inert hydrocarbon solvent is used. 11. The cation exchange resin is partially esterified with a mercapto-alcohol. <EMI ID = 328.1> cation exchange groups of said resin. 13. Mercaptoalcohol is an alkyl mercaptoalcohol having one to six carbon atoms in the alkyl group. <EMI ID = 329.1> 15. The resin has an exchange capacity of at least two milliequivalents per gram of resin. B - Continuous process for the manufacture of 2,2-bis- (4-hy- <EMI ID = 330.1> phenol being in excess compared to the stoichiometric amount, <EMI ID = 331.1> <EMI ID = 332.1> ne under substantially anhydrous conditions in a sono reaction <EMI ID = 333.1> action and phenol and the other stream containing acetone, water and phenol, removing reaction byproducts <EMI ID = 334.1> propane, and recycling us-produced reaction of phenol and acetone to the reaction zone. <EMI ID = 335.1> per mole of acetone. 3. Renin is partially esterified with a mercaptoaloool. <EMI ID = 336.1> sine are esterified with a meroapto-alcohol. <EMI ID = 337.1> by weight of water. 6. The feed for the reaction contains less than 0.2% by weight of water. 7. Phenol and acetone react at a temperature of <EMI ID = 338.1> 9. At least part of the acetone and phenol are maintained in the reaction zone in the liquid phase for a sufficient period of time. <EMI ID = 339.1> tone. 10. The effluent is separated into two streams at a temperature <EMI ID = 340.1> 11. The separation of the effluent is carried out such that the stream containing the adduct contains between 4 and 10 moles of phenol per mole of 2,2-bie- (4-hydroxyphenyl) -propane. 12. Cool the stream containing the adduct <EMI ID = 341.1> adduct, the adduct is separated therefrom, the remainder of the stream is recycled to the reaction zone, the product is treated. <EMI ID = 342.1> and recycling the phenol from the adduct to the reaction zone. 13. The stream containing the adduct is cooled. <EMI ID = 343.1> 14. Anhydrous acetone and phenol are obtained from the stream containing acetone, water and phenol by contacting the stream with the rising anhydrous acetone vapors; a certain quantity of acetone and all the water are distilled off in the form of a binary system which is separated from the current; the anhydrous phenol and the anhydrous acetone are recovered as a residue; the binary acetone-water system is subjected to distillation and the anhydrous acetone is recovered as a distillate. C - Process for the manufacture of 2,2-bis- (4-hydroxyphenyl) -propane, consisting in reacting phenol and acetone in a reaction zone, in contact with an acid condensing agent, removing from the reaction zone an effluent comprising 2,2-bis (4-hydroxyphenyl) propane. phenol, acetone, water and by-products of the reaction of phenol and acetone, and in concentrating the effluent by removing substantially all of the water, this process being characterized by the following points, taken singly or in combination: 1. The concentrated effluent is brought into contact, when it has a water content of less than 1.5% by weight, with a porous mass of cation exchange resin which is substantially insoluble and saturated with phenolic solvent, placed in a zone of transposition, and at least some of the by-products are still reacted of the reaction of acetone and phenol, to form 2,2-bis- (4-hydroxyphenyl) -propane. 2. The concentrated effluent is subjected to the transposition reaction when its water content is less than 0.5% by weight. 3. The acidic condensing agent of phenol and acetone is activated by sulfur. 4. The transposition zone is maintained at a temperature between 50 [deg.] And 100 [deg.] C. 5. The zone of the condensation reaction of phenol and acetone comprises a porous mass of cation exchange resin, practically insoluble, saturated with phenolic solvent and which has been partially esterified with a mercapto-alcohol. 6. The transposition zone is maintained between 60 [deg.] And 90 [deg.] C and the effluent from the transposition zone is passed into the zone of the condensation reaction of phenol and acetone. 7. The transposition zone is maintained at approximately 75 [deg.] C. 8. The effluent from the phenol-acetone condensation reaction zone is concentrated by separating therefrom acetone and substantially all of the water, and the 2,2-bis- (4-hydroxyphenyl) is separated. -propane from the effluent. 9. The effluent is brought into contact, after having separated the water and the acetone, but before having separated the 2,2-bis (4-hydroxyphenyl) propane, and when the water content of the effluent is lower at about 0.5% by weight, with the porous mass of cation exchange resin to effect the transposition. <EMI ID = 344.1> concentrated as an adduct of one mole of 2,2-bis- (4-hydroxyphenyl) -propane For one mole of phenol, the cation exchange resin of the condensation reaction zone, like the resin of the transposition zone, has been partially esterified with a mercapto-alcohol, and the temperature of the zone of <EMI ID = 345.1> D - As new industrial products: 1. Bisphenols obtained by any of the processes described under A, B or C. 2. A cation exchange resin partially esterified with a mercapto-alcohol, as described in the process specified under A 11.