DE4129545C1 - Prodn. of finely divided aq. sodium bis:phenolate - by mixing bisphenol=A with sodium hydroxide to ppte. prod. and stirring vigorously - Google Patents

Abstract

Prodn. of finely divided aq. Na bisphenolate suspension comprises rapid mixing of fused 2,2-bis(4-hydroxyphenyl)propane, "Bisphenol-A", (1 mol) with aq. NaOH (1.5-2.2 mol) to obtain an aq. soln. at 60-90C contg. 15-40 pts. wt. solids in 100 pts. wt. water, when up to 50 wt.% of the prod. precipitates; then stirring vigorously so that the mixture cools to 10-35deg.C within 1-1800s. USE - The prod. is a raw material for the prodn. of polycarbonates.

Description

In the production of polycarbonates, that has changed Technically proven two-phase interface process. As continuous process, it usually has the aftermath part that to accelerate the reaction and Ver better phase separation more phosgene used must be than is necessary for the product balance. The Excess phosgene is then synthesized in the form of By-products - for example additional table salt or alkali carbonate compounds - degraded.

There has been no shortage of attempts at this phosgene lower shot. Some of the improvement measures relate to the use of special bisphenolate Solutions. Furthermore, according to the prior art Range of different dosing and reaction instructions previously described.

To reduce monocarbonate residues in the EP 2 62 695 and EP 3 69 422 described measures in de nen those formed from chain terminators and phosgene Monocarbonate oligomers, among other things, by replenishing of the chain breaker can be avoided.  

DOS 23 05 144 describes a process for continuous Nuclear production of polycarbonates, in which the two reactive phases in the presence of amines in one Mixing zone with essentially oil-in-water emulsions and the phosgenation in a reaction path after mixing. Specially le fluidic arrangements should ensure that the space-time yield of the reaction is increased. A disadvantage is the large amount of aqueous phase Phosgene side reactions supported.

According to DOS 23 53 939, the properties of a Polycarbonate manufactured according to the two-phase limit surface method, by controlling the reaction with a pH regulation can be improved. Disadvantageous is the excess phosgene used. The Ver driving is also non-continuous.

According to the teaching of EP 02 82 546, condensates should also be used Chloroformyl end groups with good phosgene yield manufactured by the two-phase interface process can be that one is presented in an organic Phase at the same time a stable diphenol-water-soda alkali suspension and phosgene are continuously mixed in and then isolating the reaction product. While pH values between 2 and 5 are introduced into the reaction poses. Technical difficulties are a disadvantage the dosage of the suspension and the low pH, which significantly increases the phosgenation time. activities for a polycondensation are not described here ben.  

From EP 02 63 432 it can be learned that condensates with Chloroformyl end groups or polycarbonates from aqueous Diphenolate solution and organic solution can be set that at pH values between 8 and 11, temperatures between 15 and 50 ° C and one Phosgene excess of at least 10 mol% phosgene in one mixed heterogeneous mixture and the phosgenation un ter simultaneous dosing of alkali or alkaline kaliaugen continues. Preferred phase relationships are 0.4 to 1 to 1 water to oil ratios, being water is replenished.

The teaching of DOS 27 25 967 shows that it is for the phosgene yield of a continuous process is favorable, aqueous and organic phase, the phosgene contains dissolved, first merge in a tube and then insert it into a tank type reactor. The Residence time in this tube should be between 0.5 and 15 Seconds. The excess phosgene of the reaction is at least 10 mol%. It is always a disadvantage still quite high excess of phosgene. In addition, the ver drive the disadvantage that the phosgenation at unfavorable phase relationships (oil to water = 0.2 to 1) takes place so the separation of the two phases after Completion of the reaction is certainly possible.

According to EP 03 06 838 A2 the phosgenation is under Use of an automatic C1 detector in situ supervised. Fluctuations occur due to the process control suppressed in the chemism of the reaction and the techni properties of the polycarbonates are said to be clear improved. The basic idea of the process is there  rin, unreacted diphenolate back into the process respectively. However, the phosgene additions are disadvantageous reactions that are also reflected in this return measure express.

According to EP 03 39 503 A2 it is known that the phosgene Side reactions can be increased in particular that there is a high concentration of sodium hydroxide solution. In This patent therefore describes the diphenol sodium hydroxide solution Water solution in an alkali-hydroxy ratio of less than 2: 1 (Alkali lye deficit) with the organic phases too brought together, in this first reaction stage oligomers with molecular weight between 300 and Form 3000 g / mol. The phase ratios of water to oil are greater than 1. In addition, the phosgene side cracks still very unfavorable.

EP 03 04 691 A2 shows that - however with a very high excess of phosgene (20 to 100 mol% Excess) - in the two-phase interface method fine emulsion - achieved through high mixing performance - for the course of the reaction is favorable. The high phosgene sentence causes a good phase separation despite intensive Mix the emulsion at the start of the reaction. The However, phosgene yield is quite unfavorable.

WO 88/01 996 describes a process for the production of reaction products from phosgene and dihydroxyphenols described. The introduction of special bisphenol suspensions ion should reduce phosgene side reactions and the Make the process easier to manage. It is from one Mixture of crystalline bisphenol-A, alkali and  Water in certain compositions and from this mixture by stirring vigorously produces at least 30 minutes of stable suspension which for example polycarbonate synthesis continuously or is added discontinuously. Preferred To compositions of the suspension are 47.9 to 52.0% Bisphenol-A, 52 to 47.9% water and 0.01 to 0.2% Alkaline solution. In addition, in general ratios between 20 and 50% bisphenol-A, 8 to 16% Alkaline solution and 40 to 70% water can be used. Usual Phosgene temperatures are between 14 and 40 ° C. The Suspensions are not very fine suspensions and time for their manufacture, especially when used in a continuous response, too long since the kri stallinen bisphenol A particles first in the Suspen sion must be "solved".

In US 44 47 655 a special cleaning ver drive for bisphenol-A, which is washing of bisphenol A suspensions with an organic Detergent in a continuous, multi-flush Countercurrent extraction column teaches. Here is going visually the suspensions indicated that the Water to bisphenol-A ratio for washing none Role should play. The suspensions are made by - starting from a bisphenol melt - water low temperature is entered with stirring, so that the mixture at temperatures of 60 to 70 ° C ge is cooled, and then crystals from the form aqueous solution by further cooling, which the described cleaning can be subjected.  

According to AT 3 41 225 bisphenolate suspensions have before divide when used as aqueous solutions in the two phase interface reaction because with them polycarbonates high raw material yield and good quality can be achieved can. In addition, these suspensions have the advantage part that little water used in the reaction becomes.

When using suspensions, it is not always a fold to do the chain breaker at the appropriate moment sieren. The reaction is either quite far advanced or there is due to inhomogeneous ver division of the suspension particles has not yet reacted Bisphenolate.

It was surprisingly found that these disadvantages ver can be avoided by using a bisphenol with ket terminator and / or with another bisphenol the principle of using the solubility product matches and co-ordinated precipitation in the Two-phase interface reaction as an aqueous suspension or as anhydrous phenolate particles for the manufacturers use of polycarbonates.

The subject of the present invention is  a process for the preparation of suspensions of bisphenolates with at least partial spherical shell morphology, which is characterized in that one

• a) a warm between 50 and 90 ° C, saturated at this temperature Solution of a bisphenol in sodium hydroxide solution and water,
• b) with a fine suspension warm between 10 and 50 ° C alkali bisphenolate or alkali monophenolate as chains terminator, with a maximum of 50% of the bisphenol or the chain terminator are dissolved in the aqueous phase,
• c) with intensive mixing while avoiding temperatures above half 50 ° C brings together, the proportions a) and b) are chosen so that due to cooling from solution a) Bisphenolate fails.

These suspensions according to the invention can either un indirectly used for the production of polycarbonate or by removing water to special bispheno lat particles with spherical shell morphology worked up be, which then also for production of polycarbonates can be used.

The present invention thus also relates to Process for working up the suspensions according to the invention sions, characterized in that the invention dehydrated according to suspensions.  

Another object of the invention is the use of the suspensions according to the invention for the production of Polycarbonates.

Another object of the invention is the use of bisphenolate particles with spherical shell morphology for the production of polycarbonates.

Suitable diphenols are those of the formula HO-Z-OH, in which Z is an aromatic radical having 6 to 45 carbon atoms, which may contain one or more aromatic nuclei, may be substituted and aliphatic radicals or cycloatliphatic radicals or heteroatoms as bridges may contain limbs. examples are
Hydroquinone,
Resorcinol,
Dihydroxydiphenyls,
Bis (hydroxyphenyl) alkanes,
Bis (hydroxyphenyl) cycloalkanes,
Bis (hydroxyphenyl) sulfides,
Bis (hydroxyphenyl) ether,
Bis (hydroxyphenyl) ketones,
Bis (hydroxyphenyl) sulfones,
Bis (hydroxyphenyl) sulfoxides,
alpha, alpha'-bis (hydroxyphenyl) diisopropylbenzenes
and their nuclear alkylated and nuclear halogenated compounds.

These and other suitable other diphenols are e.g. B. in US-PS 30 28 365, 29 99 835, 31 48 172, 32 75 601, 29 91 273, 32 71 367, 30 62 781, 29 70 131 and 29 99 846, in DOS 15 70 703, 20 63 050, 20 63 052, 22 11 956, French Patent 15 61 518 and described in DE-OS 38 33 953 (Le A 26 397).

Preferred diphenols are
2,2-bis (4-hydroxyphenyl) propane (bisphenol-A)
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA)
1,1-bis (4-hydroxyphenyl) cyclohexane (bisphenol-Z)
1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane (HIP-bisphenol).

Suitable chain terminators are known monofunctional ones phenolic compounds, especially para-tertiary-Bu tylphenol and alkylphenol chain terminators in which the alkyl radical consists of 8 or 9 carbon atoms and ver branches.

The suspension of monophenolate salts are known process available. Also the diphenolate suspension NEN and the diphenolate solutions are according to the state of technology available.

Method step b) is a Sus Pension of a different bisphenol than that in a) above wrote or a suspension of a no good what ser soluble chain terminator, the suspension after the state of the art by known methods - at for example by direct merging of aqueous  Sodium hydroxide solution with a bisphenol melt or by mixing of fine bisphenol powder in aqueous sodium hydroxide solution - was produced. What is essential is a fine one and even particle distribution. According to known Her Such a suspension will be provided by Tempe temperatures between 10 and 50 ° C, preferably 20 to 40 ° C submitted. The concentration of chains used crusher or bisphenol in this suspension - based on the total mass of the suspension - is chosen so that at most 50%, preferably at most 30%, in particular not more than 10% of the bisphenol or Chain breaker are dissolved in the aqueous phase, the means that the solubility limit is with regard to the con concentration exceeded by at least a factor of 2.

In measure c) a desired amount of bis is now phenolate solution according to measure a) in a desired, predetermined amount of suspension according to measure b) below intensive mixing and avoiding temperatures above 50 ° C - if necessary by intensive cooling - merged. Bisphenolate falls into the solution a) from the mixture of solutions a) and b).

The operating conditions are chosen so that little at least 10% of the suspension nuclei of solution b) as a precipitate germs for the precipitated bisphenol particles of the solution a) act, what through the temperature control and the Mi is achieved in accordance with measure c). This can be done also by increasing or decreasing the mix performance can also be optimized. In general the mixing powers are between 0.5 and 2 watts / l, preferably at more than 1 watt / liter.  

This mixed suspension is generally added to the Beibe maintenance of a low mixed power input with a organic solution containing phosgene Polycarbonate reaction brought together, the orga African solution preferably from solvents such as methylene chloride, monochlorobenzene or mixtures of both be stands and the solution per mole of bisphenol-A between 1.05 Moles and 1.35 moles, preferably less than 1.25 moles of phosgene contains. After phosgenation, the solution is under Addition of known catalysts, chain terminators and white known sodium hydroxide solution in known amounts to polycarbonate reacted and this from the emulsion in known Wei se isolated.

Adjust the proportions of solutions a) and b) the desired polycarbonate, which is made from the Mixed suspension or the dewatered mixed suspension Particles should be produced.

For the production of a polycarbonate with a given Molecular weight is given to essentially water insoluble chain terminator in solution b) before and leads the required molar amount of the to be used Bisphenols in solution a) - controlled by the amounts relationships a) to b) - in measure c) together. Poly Carbonates generally have molecular weights here Mw between 15,000 g / mol and 200,000 g / mol, preferred 18,000 g / mol and 40,000 g / mol. Your uniformities Un = Mw / Mn-1 can be between 0.2 and 5, preferred between 0.2 and 3, in particular between 0.3 and 2 lie. The synthesis can be carried out on suitable known ones Branches are also added.  

For the production of block polycarbonates, the Men Ratios a) to b) chosen so that b) the bad contains the soluble bisphenol in the required amounts and a) the more easily soluble.

The suspension according to the invention can directly - that is with partially dissolved bisphenols / chain terminators Solutions a) and b) - used in polycarbonate synthesis be set.

But you can also first by known methods Filter off suspension particles, dewater and on concluding these particles for the polycarbonate reaction - if necessary suspended in water for a short time - ver turn. This is done together with an organic solvent solution with phosgene. The polycarbonate is then replaced by Fil tration of the saline particles and subsequent precipitation or evaporation isolated.

The bisphenolate particles can be both continuous and discontinuously turned to polycarbonate production be set. The separate addition of chain terminators is generally not required. The available ones Polycarbonates have the usual known properties and possible uses in the field of optics and Electrical engineering.

example

In a 1-1 laboratory reactor with a blade stirrer the following example was carried out. The Reactor is provided with a cooling jacket over which at If necessary, the heat of reaction can be removed. Ange a temperature-controlled supply is connected to the reactor vessel, from the aqueous NaBPA solution suddenly into the Reactor can be metered.

220 g of methylene chloride and 220 g were placed in the reactor Monochlorobenzene and 35.6 g (0.36 mol) of phosgene dissolved with vigorous stirring at room temperature.

200 g of water, 68.5 g of BPA were placed in the storage vessel (0.3 mol) and 24.4 g NaOH (0.61 mol) to approx. 80 ° C warms and mixed intensely until a homogeneous solution originated. In another storage jar one Suspension on 15 g water and 1.85 g isooctylphenol (0.009 mol) and stirred at 40 ° C. The bis phenolate solution was stirred vigorously (1.4 Mbit / Li ter) and while cooling the further storage vessel in this stirred in, some of the bisphenolate was noticed the chain terminator suspension particles, partly as fine precipitation, from.

This aqueous suspension was stirred vigorously dosed suddenly into the reactor. The temperature of the resulting emulsion rose during phosgenation to approx. 50 to 53 ° C. After ten minutes, 3.2 g 25% NaOH (0.02 mol) was added. After 30 minutes were 1.36 g of 5% N-ethylpiperidine solution in methylene  chloride and 19.2 g 50% NaOH (0.24 mol) added. The Temperature was kept at 30 ° C. After another 10 mi The reaction was stopped by the stirrer turned off and the emulsion was separated.

Analysis: molecular weight of the polycarbonate: Mn = 16,000 g / mol, BPA content of the mother liquor: 1 ppm, Carbonate content of the mother liquor (aqueous phase): 0.6%. The reaction resulted in a high yield of phosgene and an easily separable emulsion.

Claims (4)

1. A process for the preparation of suspensions of bisphenolates with at least partial spherical shell morphology, characterized in that

• a) a solution of a bisphenol in sodium hydroxide solution and water which is between 50 and 90 ° C warm and saturated at this temperature,
• b) chain terminators with a fine suspension of another alkali bisphenolate or alkali monophenolate warming between 10 and 50 ° C., at most 50% of the bisphenol or chain terminator used being dissolved in the aqueous phase,
• c) brings together with intensive mixing avoiding temperatures above half 50 ° C, the quantitative ratios a) and b) being chosen such that bisphenolate precipitates out of solution a) due to cooling.

2. Process for working up the suspensions obtained according to claim 1, characterized in that they are dewatered. 3. Use of the suspensions obtained according to claim 1 for the preparation of polycarbonates. 4. Use of the bisphenolate particles obtained according to claim 2 for the Manufacture of polycarbonates.