阅读说明：本技术 具有减少的光气过量的制备聚碳酸酯的方法 (Method for producing polycarbonates with reduced phosgene excess ) 是由 R·巴赫曼 V·米歇尔 J·海尔 F·可克 于 2020-03-30 设计创作，主要内容包括：本发明的主题是通过相界面法由至少一种二羟基二芳基烷烃、光气、至少一种催化剂和至少一种链终止剂制备聚碳酸酯的方法,其中该方法通过给定的用于分散水相和有机相的能量输入能够实现减少的光气过量。此外,该方法提供具有低的低聚物比例和低的二-链终止剂碳酸酯比例的聚碳酸酯。(The invention relates to a method for producing polycarbonates by the phase interface method from at least one dihydroxydiarylalkane, phosgene, at least one catalyst and at least one chain terminator, wherein the method enables a reduced phosgene excess by means of a given energy input for the dispersion of the aqueous and organic phases. In addition, the process provides polycarbonates having a low proportion of oligomers and a low proportion of di-chain terminator carbonates.)

1. Continuous method for producing polycarbonates by the phase interface process from at least one dihydroxydiarylalkane, phosgene, at least one catalyst and at least one chain terminator, comprising the following steps

(a) Producing a dispersion from an organic phase and an aqueous phase by continuously dispersing the organic phase in the aqueous phase or the aqueous phase in the organic phase in a disperser, wherein the organic phase comprises at least one solvent suitable for polycarbonates and at least a portion of phosgene, and the aqueous phase comprises at least one dihydroxydiarylalkane, water and from 1.8 to 2.2 mol, preferably from 1.95 to 2.05 mol, of an aqueous alkali metal hydroxide solution per mole of dihydroxydiarylalkane,

(b) adding at least one chain terminator to the dispersion from step (a), and

(c) adding at least one catalyst to the mixture obtained from step (b),

it is characterized in that the preparation method is characterized in that,

step (a)) Wherein the energy input by the disperser is 2.5 xe⁶ W/m³To 5.0 × e⁷ W/m³Preferably 3.0 × e⁶W/m³To 4.0 × e⁷ W/m³Particularly preferably 1.0 × e⁷ W/m³To 3.5 × e⁷ W/m³。

2. The continuous process according to claim 1, characterized in that a water-in-oil dispersion is produced in process step (a).

3. A continuous process according to any one of claims 1 or 2, characterized in that the process comprises at least one step of adding an aqueous alkali metal hydroxide solution.

4. The continuous process according to claim 3, characterized in that the addition of at least one chain terminator into the reaction system in process step (b) is carried out temporally before the first addition of the at least one addition of aqueous alkali metal hydroxide solution.

5. The continuous process according to any one of claims 1 to 4, characterised in that in process step (a) there is a phosgene excess of 3 to 20 mol%, preferably 4 to 10 mol%, particularly preferably 5 to 9 mol%, relative to the sum of the dihydroxydiarylalkanes used.

6. The continuous process according to any one of claims 1 to 5, characterized in that the at least one catalyst is selected from tertiary amines and organic phosphines.

7. Continuous process according to any one of claims 1 to 6, characterised in that the at least one chain stopper is chosen from phenols, alkylphenols and chlorocarbonates thereof or acid chlorides of monocarboxylic acids, preferably from phenol, tert-butylphenol and isooctylphenol, cumylphenol.

8. The continuous process according to any one of claims 1 to 7, characterized in that the at least one dihydroxydiarylalkane is selected from the group consisting of 4,4' -dihydroxybiphenyl, 1, 1-bis- (4-hydroxyphenyl) phenylethane, 2, 2-bis- (4-hydroxyphenyl) propane, 2, 2-bis- (3, 5-dimethyl-4-hydroxyphenyl) propane, 1, 1-bis- (4-hydroxyphenyl) cyclohexane, 1, 1-bis- (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane and any mixtures thereof.

9. The continuous process according to any one of claims 1 to 8, characterised in that at least one nozzle, perforated pipe, static mixer, pump and/or jet disperser is used as disperser in process step (a).

10. The continuous process according to any one of claims 1 to 9, characterised in that at least one chain terminator is introduced into the reaction system comprising at least the at least one dihydroxydiarylalkane, phosgene and the reaction product R from the at least one dihydroxydiarylalkane and phosgene at a point in time in process step (b) at which point the reaction product R is a mixture of compounds and these compounds have on average a degree of polymerization of at least one unit and at most six units, the unit being formed from the at least one dihydroxydiarylalkane by reaction with phosgene.

11. The continuous process according to claim 11, characterized in that the compounds of the mixture of reaction products R are represented by the general chemical formula (I):

wherein

R₁And R₂Each, independently of the others, is H, C1-to C18-alkyl, C1-to C18-alkoxy, halogen, such as Cl or Br, or is in each case optionally substituted aryl or aralkyl, preferably H or C1-to C12-alkyl, particularly preferably H or C1-to C8-alkyl, very particularly preferably H orThe methyl group is a group selected from the group consisting of,

R₃is H, (C = O) -Cl or (C = O) -OH,

R₄is an OH group or a Cl group,

x is a single bond, -SO₂-, -CO-, -O-, -S-, C1-to C6-alkylene, C2-to C5-alkylidene or C5-to C6-cycloalkylidene which may be substituted by C1-to C6-alkyl, preferably methyl or ethyl, and furthermore C6-to C12-arylene which may optionally be fused with further aromatic rings comprising heteroatoms, and

n is the degree of polymerization, and thus the number of units formed by the reaction of at least one dihydroxydiarylalkane with phosgene, and may have an average value of 1 to 6.

12. 2.5 × e⁶ W/m³To 5.0 × e⁷ W/m³Preferably 3.0 × e⁶ W/m³To 4.0 × e⁷ W/m³Particularly preferably 1.0 × e⁷ W/m³To 3.5 × e⁷ W/m³To a system comprising an organic phase and an aqueous phase in order to reduce the phosgene excess in the preparation of polycarbonates by the phase interface process, wherein

The organic phase comprises at least one solvent suitable for polycarbonates and at least a portion of phosgene, and

the aqueous phase comprises at least one dihydroxydiarylalkane, water, from 1.8 mol to 2.2 mol, preferably from 1.95 mol to 2.05 mol, of aqueous alkali metal hydroxide solution per mole of dihydroxydiarylalkane and optionally at least one chain terminator.

13. Use according to claim 12, wherein the energy input is performed by a disperser.

14. Use according to any one of claims 12 or 13, characterized in that the process for the preparation of polycarbonate by the phase interface process is carried out continuously.

15. Use according to any one of claims 12 to 14, characterized in that a phosgene excess of 3 to 20 mol%, preferably 4 to 10 mol%, particularly preferably 5 to 9 mol%, relative to the sum of the dihydroxydiarylalkanes used, is used.

Examples

The molecular weight distribution and the mean values Mn (number average) and Mw (weight average) were determined by means of Gel Permeation Chromatography (GPC). The instrument comprises the following steps: waters "Mixed Bed" column) with methylene chloride as eluent (using a BPA homopolycarbonate standard with an Mw of 31000 g/mol).

In addition to the routine evaluation, the deviation of GPC from the ideal Schulz-Flory distribution was also determined. For this purpose, the GPC is first normalized, so that the area under the solid line of the curve of fig. 1 is obtained. The area is normalized to 1. Furthermore, the Schulz-flory (sf) distribution was adjusted such that its maxima in height and molecular weight were consistent with the measured distribution (dotted line in fig. 1). The difference between the measured and adjusted SF distribution gives the difference distribution (dashed line in fig. 1). In the present case, the Schulz-Flory distribution is narrow, so the differential distribution is positive (except for measurement inaccuracies). Due to this method, the difference at the maximum is zero, so the difference distribution is broken down into a low molecular weight fraction and a high molecular weight fraction (see also fig. 1 for this).

It is known from the prior art that a high oligomer proportion is detrimental to the product quality. However, only the total proportion of low-molecular-weight compounds or the proportion soluble in acetone below certain limits is generally taken into account here. This has the disadvantage that unavoidable oligomer proportions are also taken into account, which proportions also vary with the type of polycarbonate (viscosity, Mn). The method of the invention corrects for this dependence and determines only the method-specific oligomer ratio.

2,2' -bis- (4-hydroxyphenyl) propane (bisphenol A, BPA) was used as the dihydroxydiarylalkane, and the solvent for the organic phase was a mixture of about 50% by weight of methylene chloride and 50% by weight of monochlorobenzene. Polycarbonates having the stated weight average molecular weights were prepared in all examples and were measured by GPC (Waters "Mixed Bed" column in methylene chloride with BPA homopolycarbonate standard having an Mw of 31000 g/mol).

Example 1 reduction of phosgene excess

Continuous laboratory experiments were conducted in a combination of pump and stirred reactor. In all experiments 70.1 g/h of gaseous phosgene were dissolved in 772 g/h of organic solvent (1: 1 dichloromethane/chlorobenzene) in a T-tube at-7 ℃. The amount of solvent was calculated to finally obtain a 15 wt% polycarbonate solution. The phosgene solution fed continuously was contacted in a further T-piece with 912g/h of a 15% by weight aqueous alkaline BPA solution (2mol NaOH/mol BPA), which had been preheated to 30 ℃. The BPA solution was dispersed in the phosgene solution (pore size 60 μm) through a stainless steel filter as a pre-disperser. In all cases a water-in-oil dispersion was obtained. The energy input given in table 1 was then generated by a rotodynamic pump.

The reaction mixture was conducted to a Fink HMR040 mixing pump which was tempered at 25 ℃ so that phosgene had reacted as completely as possible at the end of the reaction pump, but was still present. After the pump, atExamples 1a, 1c and 1d3.29 g/h of p-tert-butylphenol as 3% by weight solution were metered into the same solvent mixture as described above as chain terminator and the reaction mixture was further reacted with 53.95g/h of 32% by weight aqueous sodium hydroxide solution at 25 ℃ in a further HMR040 pump to give a pH at the end of the reaction system of about 11.5. In thatExample 1b3.29 g/h of p-tert-butylphenol as a 3% by weight solution were added here as chain terminator to the same solvent mixture as described above.

This is followed by 2 stirred tanks from Ismatec with one gear pump each. 0.679 g/h of catalyst (10% by weight of N-ethylpiperidine dissolved in chlorobenzene) are metered in between two stirred tanks (and gear pump) in a T-piece in a Teflon hose.

A total of 156g of polycarbonate in organic solution were obtained continuously and passed together with the aqueous phase from the reaction into a phase separation vessel for separation. The polycarbonate solution was washed with 10% by weight HCl and dried at normal pressure and room temperature.

Table 1 summarizes the results obtained in example 1:

TABLE 1

	Energy input	Excess of phosgene	Mn 0	T device	Diff. id. MGV (PC)	Di-chain terminator Carbonic ester (PC)	CO3	Mn (PC)	Mw (PC)
											W/m3	%	g/mol	℃	Area%	ppm	By weight%	g/mol	g/mol
Practice of Example 1a	3.00 * e7	16.2	750	35	2.72	< 50	0.65	10580	26980
										Practice of Example 1b	3.00 * e7	16.2	3470	35	8.10	< 50	0.65	7870	26160
Practice of Example 1c	3.00 * e7	9.5	660	25	2.78	< 50	0.38	9800	26200
										Practice of Example 1d	3.00 * e7	7	730	25	2.50	< 50	0.33	9990	25300

Mn0 molecular weight when chain terminator was added

Diff id. MGV (PC) differential distribution; see the explanation above.

Example 1a shows that, by means of the high energy input in process step (a), polycarbonates having a low content of oligomers and di-chain terminators can be obtained. In example 1b, the chain terminator was added later.

Examples 1c and 1d according to the invention show that phosgene excesses can additionally be reduced in the case of high energy inputs. At the same time, polycarbonates having good or even improved oligomer and di-chain terminator carbonate contents are obtained. In example 1b, the addition of NaOH is carried out temporally before the addition of the chain terminator. However, the addition of the chain terminator proceeded so early that phosgene was therefore assumed to be still present in the reaction system.

The addition of the chain terminator at the point in time at which phosgene is no longer present in the reaction system means that the reaction product R has on average an even higher molecular weight. Even higher proportions of oligomers are thus to be expected.

Example 2

The devices used as individual method steps:

method step (A) disperser in the form of an orifice nozzle with predispersion (orifice plate with 5 bores each 2.5 mm in diameter, 2.35 in thickness, 0.2 bar pressure drop at a flow rate of 5.2 m/s), residence time in the predispersion space of 26 ms (in examples 2a and 2b the aqueous phase is dispersed in the organic phase by the predispersor; in comparative example 2c the organic phase is dispersed in the aqueous phase by the predispersor) and subsequent dispersion (with a further orifice plate with 18 bores each 1.5 mm in diameter, 2.35 mm in thickness, 0.8 bar pressure drop at a flow rate of 8.9 m/s) andcomparative example 2cIn (which corresponds to example 1 of DE102008012613 a 1; an orifice plate having a further 18 bores, each bore having a diameter of 1.0 mm, an orifice plate thickness of 2.35 mm, a pressure drop of 0.8 bar at a flow rate of 8.9 m/s in examples 2a and 2b according to the invention), is dispersed in the other by one of the liquids.

Process step (B), a residence time reactor with a residence time of 0.2s at 600kg/h (bisphenol solution).

Method step (C) A circulation pump reactor equipped with a metering point (for example for NaOH), a pump, a heat exchanger, an overflow vessel and a T-shaped withdrawal point, having a volume of 140 l, with a pH probe and a conductivity probe; redispersing the mixture when the mixture enters a circulating pump reactor; in example 2a, chain terminator was added to the circulating pump reactor.

Process step (D) with a discharge pump for the metering point upstream of the chain terminator (in example 2b and comparative example 2c, chain terminator is added here; in example 2a, nothing is added here) and NaOH solution, between which is a static mixer, downstream is a serpentine reactor with a mixing zone and a residence zone and a total volume of 60 liters (first residence reactor), and downstream is another serpentine reactor with a metering point for the catalyst at the beginning of the reactor and a total volume of 80 liters (second residence reactor).

Subsequent phase separation intoFrom the container (size 4.15 m)³Fill level 50%).

The following streams were used in process step (a):

in examples 2a and 2b 500kg/h of aqueous bisphenol solution (15% by weight mixture of bisphenol A and bisphenol TMC, based on the total weight of the solution, 2.13mol NaOH/mol bisphenol solution) (phosgene stream and stream of solvent mixture (see below) are proportionally adjusted accordingly to the reduced bisphenol stream)

Or

In comparative example 2c 600kg/h of an aqueous bisphenol solution (15% by weight of bisphenol A, based on the total weight of the solution, 2.13mol of NaOH per mol of bisphenol solution)

44.6 kg/h phosgene

520 kg/h of a solvent mixture of 54% by weight of methylene chloride and 46% by weight of chlorobenzene

No additional streams are additionally used in process steps (B) and (C).

In process step (D), the following streams are additionally used before the first residence reactor:

17.8 kg/h of a tert-butylphenol solution (20% by weight in a solvent mixture of 54% by weight of methylene chloride and 46% by weight of chlorobenzene)

35 kg/h of an aqueous NaOH solution having 32% by weight of NaOH

In process step (D), the following streams are additionally used in the second residence reactor:

22.7 kg/h catalyst solution (3% by weight solution, ethylpiperidine in a solvent mixture of 54% by weight dichloromethane and 46% by weight chlorobenzene).

The temperature in the circulating pump reactor was 35 ℃ (after the heat exchanger) to 38 ℃ (before the heat exchanger). The temperature in the serpentine reactors in process step (D) was each 37 ℃ and the temperature in the disengaging vessel was 35 ℃.

The direction of dispersion is set such that the organic phase is dispersed in the aqueous phase.

Table 2 summarizes the results obtained.

TABLE 2

Energy input

Dispersing

Mn Loop

T device

Diff. id. MGV

Di-chain terminator carbonic acid Ester (PC)

CO3

Mn (PC)

Mw (PC)

W/m3

g/mol

℃

Area%

ppm

By weight%

g/mol

g/mol

Example 2a

4.2 * e6

wo

< 900*

60

3.50

200

0.75

12020

31650

Example 2b

4.2 * e6

wo

2320

60

5.00

< 20

0.76

10240

29026

Comparative example 2c

1.2 * e6

ow

2210

50*

6.20

< 50

0.64

8750

24450

Estimated value

MnLoop molecular weight at addition of chain terminator

Diff id. MGV (PC) differential distribution; see the explanation above.

In examples 2a and 2b, a 19% excess of phosgene was used. In comparative example 2c, a 15% excess of phosgene was used. Since the bisphenol solution of the comparative example had a different composition from the example according to the present invention, it was necessary to adjust the phosgene excess.

It can be seen, however, that polycarbonates having a relatively high oligomer proportion are obtained by the energy input disclosed in the examples of DE 102008012613A 1. By increasing the energy input (examples 2a and 2b according to the invention), it is possible to reduce this ratio while maintaining an acceptable content of di-chain terminator carbonates. Due to the different energy inputs, in examples 2a and 2b according to the invention there is a water-in-oil dispersion in process step (a) and in comparative example 2c there is an oil-in-water dispersion.

It can also be seen in these examples that the point in time of addition of the chain terminator brings about further advantages in terms of the content of oligomers and di-chain terminator carbonates.