JPS5831203B2 - How to use the service - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the use of membranes for solvent extraction with two liquids that are virtually immiscible and to a novel process that has many advantages over traditional two-phase solvent extraction. .

Solvent extraction is a useful separation procedure.

In this operation, a liquid solvent C is used to transfer solute(s) A to a second liquid B in which it is dissolved.
Extract from.

Liquids B and C are immiscible or slightly miscible.

In normal operation, liquids B and C are mixed directly and then separated into two phases.

However, there are certain inherent difficulties with this direct mixing.

By way of example, foam is often generated, which has the disadvantage of reducing the mass transfer rate, for example, and prevents complete phase separation.

In order to increase the effective mass transfer area in traditional solvent extraction methods, droplets must be formed during mixing.

In such cases, powder consumption is high in processes involving liquid phase mixtures due to operations such as mixer-settlers, mechanical column stirring, etc.

Backmixing can occur when droplets are formed during mixing, leading to reduced mass transfer rates.

Also, the smaller the droplet size, the easier bubbles will form.

If solute A is to be extracted from a solute mixture in a given device, conventional operation must select a liquid solvent C that selectively extracts A from other solutes in liquid B.

However, this choice can sometimes be difficult.

In addition to this limitation, conventional solvent extraction methods suffer from high solvent losses due to entrainment, and hold-up tanks are generally required for phase separation.

The present invention, which uses a membrane system, does not suffer from the aforementioned and various other drawbacks inherent in conventional solvent extraction methods.

The present invention contemplates a novel membrane-based separation method consisting of solvent extraction that is superior to conventional solvent extraction methods and has sufficient practical importance in separation technology.

In the membrane solvent extraction method of this invention, two liquids B and C, which are virtually immiscible, are separated by a membrane, ie, without phase contact of the two liquids.

During the extraction operation, solute(s) A diffuses from liquid B into the membrane, passes through this membrane, and finally passes into liquid C.

To provide a simple, efficient, and economical solvent extraction method for transferring solutes present in a first liquid to a second liquid using a membrane and without mixing the two liquids. is the first objective of this invention.

A mechanism for selectively extracting a substance from one liquid medium and precipitating the substance into a second liquid medium without the need for direct contact between the two media, with a large mass transfer effective area per unit volume. It is another and more specific object to provide a solvent extraction method using hollow fiber membranes.

Other objects and advantages of the invention will become apparent from the more detailed description below.

In the description, parts and percentages are by weight unless otherwise specified.

Membranes of hollow fiber, millimeter, tubular, and other shapes can be used in membrane solvent extraction methods.

However, according to a preferred embodiment, the invention provides a mechanism for separating component substance A from a first liquid medium B and introducing this substance into a second liquid medium C without mixing the two liquid mediums. It is intended to use hollow fiber membranes.

Some of the advantages of membrane solvent extraction methods involving the use of hollow fibers provided by this invention are discussed in more detail below, including:
It can be summarized as follows.

1. Utilization of large effective mass transfer area per unit volume.

For example, the outer diameter (0, D,) is 100 μm1 the inner diameter (1, D,
) is 907 zm and the fiber spacing is 20 μm (see Figure 2).
A membrane area of 7×10 3 ft 2 (based on OLD) is obtained.

2. Avoid direct mixing of the two phases, thereby eliminating foam generation.

3. Prevention of back-mixing of the two solvent phases, which sequentially selectively extracts various components in the fluid to be treated by using membranes with different selectivities.

4. Excellent selectivity - Extraction selectivity can be established through membranes.

5. High purity product.

6. Avoidance of entrainment phenomena to reduce solvent loss.

7. Elimination of hold-up tanks - no need for phase separation.

8. Practical reduction in powder consumption.

9. Flexibility in the placement of the processing equipment, ie, the equipment can be placed either vertically or horizontally.

10. Others.

In a preferred embodiment, the invention is effectively practiced using a continuous countercurrent solvent extraction apparatus, which is described in more detail below.

Using such a solvent extraction device, solute A can be extracted economically and efficiently from a solution containing the solute.

The extraction apparatus used may be a single stage, as shown in Figure 1 of the accompanying drawings, in which component A, initially present in solvent B, is removed by solvent C, or one or more solutes, as shown in Figure 4, are removed. It may be a multi-stage device for the separate extraction of solutes AI, A2 or A3 by the use of membranes with different selectivities and/or different solvents.

When using hollow fiber membranes, extraction solvent C can be arranged to pass through the hollow fibers and extract the solutes from solvent B, which contains solute A and is in contact with the outer or inner walls of the hollow fibers.

Contacting the hollow fiber membrane and separating the solute from the solute-containing solution can be accomplished using a wide range of pressures and temperatures.

However, pressures and temperatures should be used that are practical, ie compatible with the overall economics of operation of the process of this invention.

For example, 0 to 84 kg/ff1 (0 to 1200 psi
a) or higher pressure and 200° from the freezing point of the solution.
Temperatures between 25 DEG and 75 DEG C. can be used, preferably at ambient pressure.

Contact of the extraction solvent with the opposite side of the membrane, which is in contact with the solute-containing solution on one side, continues until the solute is completely removed through the membrane and into the extraction solvent.

According to a preferred embodiment, regeneration of the extraction solvent C is simply achieved by distillation.

Therefore, solvent losses through use of this invention are minimal, thus representing a significant economic advantage of this invention.

In membrane solvent extraction, the rate of mass transfer depends on the amount of diffusion of solute A through the membrane between two virtually immiscible liquid phases.

This amount of diffusion can be expressed as follows using Fick's equation.

(In the formula, F is the amount of diffusion through the membrane, D is the diffusion rate, and 4
” is the concentration change rate.

) x A diffusivity (D) of about lX10-9 to 10-W/sec is required for a constant extraction system.

Diffusion rates greater than 10' crtt/sec are usually desirable.

With this invention, the specified membrane can be used in many solvent extraction systems,
I am getting the desired results.

Selection of the optimal membrane depends on its use environment, such as diffusivity, stability of the two liquids, and optionally resistance to acids and/or bases.

Examples of interstitial membranes include Kynar (polyvinylidene fluoride)-PSSA (polystyrene sulfonic acid) copolymer, cellulose, BAMP (poly(1,7(4-methyl)azaheptaneadipamide)-nylon, NTA( Poly[1゜ω-alkylene (2,6-siketopiperazine)
-i.

4-dicarboxamide]) - nylon, nylon membrane and synthetic skin.

We define these systems as A/B/C [A is the solute(s); and B and C are two virtually immiscible liquids, and C is the other liquid B in which A is dissolved. used as a liquid solvent to extract A from

B and C may be exchanged and reversed.

] Can be used with a wide range of extraction systems listed as:

To illustrate this system in the order of A/B/C, for example, 1, ε-cabrolaccum/H2SO4/aqueous solution/HC
l3 2, ε-caprolactam/H20/CHCl33,
C2H4cz2/n-heptane 4, dinitrotoluene/H20/toluene 5, phenol/H20/toluene 6, toluenediamine/H20/dinitrotoluene 7,
Furfural/H20/Toluene In the accompanying drawings, Figures 1 and 2 show that the hollow fibers are properly arranged so that solvent C passes only through the hollow fibers and solvent B containing solute A contacts the outer wall of only the hollow fibers. This is an example of the chambers included.

A flow diagram of a typical extraction method using the hollow fiber mechanism of this invention is illustrated in FIG.

In this flow diagram, the inlet flow d is, for example, 1
．． 665 kg (3,700 ib) 7 o'clock [0.35 in water
% (3500pp111) dinitrotoluene]
to the extraction method at a flow rate of .

For example, stream O 1 consists of a contaminated stream obtained from dinitrotoluene production and is introduced into hollow fiber extraction unit I, where it is
The dinitrotoluene in stream 20 is approximately 33.84 kg (7
5,21b) Organic solvent stream 2 which is toluene at a flow rate of 7 h
It is completely extracted in 1.

This stream 21 is removed from the extraction unit as stream 22 containing a 15% concentration of dinitrotoluene and having a flow rate of 38.88 kg (86,4 lb) 7 hours and sent to a toluene nitric acid treatment unit for further processing. It can be processed as a recovered stream.

The aqueous stream 23 after extraction was 1.665 to 9 (3,700 lb
) and contains dinitrotoluene at a concentration of 2.51 pII and toluene at a concentration of about 450 pII.

Traces of toluene in stream 23 can be further extracted through the hollow fiber extraction unit 2 or treated by other means.

The organic solvent stream 24 in the extractor is a high carbon number n-alkane, such as n-decane, which is negligibly soluble in water.

Through the hollow fiber extraction unit ■, approximately 4.23 kg (9,4 ib) of toluene in stream 23 is extracted from stream 2 with a flow rate of 7 hours.
4.

After this extraction, the stream 25 leaving the extraction unit ■ contains toluene with a concentration of 15% and contains 4.995 kg (11,1 lb) 7
It has a flow rate of time.

The organic solvent, n-alkane, in stream 25 is recovered by distillation to provide stream 44, which is recycled to hollow fiber extraction unit 2.

A toluene stream 26 having a flow rate of 0.765 kg (1.7 lb) 7 hours is removed from the distillation column 28 and
73,5 lb) to form stream 21 with make-up toluene stream 27 having a flow rate of 7:00.

After passing through the hollow fiber extraction unit, stream 23 has a concentration of 2.5 ppI
dinitrotoluene at a concentration of n or less and 2.5
ppm of toluene.

The total amount of organic contaminants in stream 29 is about 5 ppm, and this stream υ can be recycled back for reuse.

It is clear that the extraction method of this invention using a hollow fiber solvent extraction mechanism is not only a recovery method but also a contaminant control method.

For this extraction method, solute A in extraction unit I is dinitrotoluene, liquid B is H20, and liquid C is toluene, and in extraction unit I, A is toluene, B is H2O1, and C is n-alkane. This is desirable.

If it is desired to separately extract multiple solutes in a stream, an extraction method using a multi-stage membrane extraction unit can be used.

The arrangement of the multi-stage membrane extraction unit is shown in FIG. 4 as an example in the case of a three-stage membrane extraction unit.

In the diaphragm, three solutes A1 in liquid B
．． The stream containing A2 and A3 is extracted through membrane extraction unit I with a second liquid C1 which is virtually immiscible with B.

This extraction unit is characterized by the selectivity of allowing only A1 to pass and not A2 and A3.

Therefore, after this first extraction, A2 and A3 are still present in B, but A1 has been transferred to C1.

Stream B containing A2 and A3 is extracted again in the membrane extraction unit Tanaka with liquid C2 which is virtually immiscible with B.

The membrane extraction unit ■ has the selectivity of allowing only A2 to pass through and rejecting A3.

Therefore, after this second extraction, A2 has been extracted into C2 and A3 is still in B.

The flow of B containing A3 is further processed into liquid C in the membrane extraction unit ■.
Extract with 3.

Liquid C3 is virtually immiscible with B.

A3 is extracted into C3. Solutes AH2A2 and A3
may differ in molecular size or chemical structure.

Liquids C1, C2 and C3 may be the same as one organic solvent or different as three organic solvents.

The following examples are illustrative of the invention.

The detailed recitation is not to be considered as a limitation on the scope of this invention.

Example 1 Film solvent extraction was performed using a two-compartment diffusion chamber.

The membrane was firmly seated between the two compartments.

Liquid B containing solute A was introduced into one of the compartments, while liquid C was poured into the other compartment.

Solute A was extracted from liquid B to liquid C through the membrane by diffusion.

In this example, a membrane 1 with a diagonal thickness of 4.58×10 was used.

The effective diffusion area of the membrane was 20.78 ffl.

Solute A was ε-caprolactam.

Liquid B was 30% H2SO4. Liquid C is CHCl3
was.

Initially, the volume of liquid B is 362 m1. Liquid C is 362m
1. The amount of solute A in liquid B is 109.6. ! i', the amount of A in liquid C was O.

After diffusion for 9.24 x 104 seconds, the measured concentration of A in B is 0.226 j9/ml, and the concentration of A in C is 0.10
9g, 4? and the amount of A in liquid C had increased to 36.2.9.

A diffusivity of 4.4 x 10'crit,/sec was obtained. Temperature and pressure were at ambient conditions.

Example 2 Additional extraction was carried out using the same method as in Example 1.

A film 2 with a thickness of 3.78×10 −3 cIrL was used.

The effective diffusion area of the membrane was 20.78i.

Solute A is ε-caprolactam, liquid B is H2O1 liquid C
was CHCl3.

Initially, the volume of B is 300d, and the volume of C is 300TL1.
The amount of A in 1B was 6 (Bi'), and the amount of A in C was O.

After diffusion for 1.44 x 10' seconds, the measured concentration of A in B is 0.18597 ml! So, the concentration of A in C is 0.017
8 g/ml, and the amount of A in C had increased to 5.44 g.

A diffusivity of 3.6 x 10 W/sec was obtained.

Temperature and pressure were at ambient conditions. Example 3 An extraction experiment was conducted by following the method of Example 1.

A film 3 having a thickness of 183×1O−2 crrL was used.

The effective diffusion area of membrane C was 16.75-.

Solute A is ε-caprolactam, liquid B is H2O1 liquid C
was CHCl3.

Initially, the volume of B is 297.5ml, and the volume of C is 296-1B.
The amount of A inside is 80.4! ! , C content was O.

After 1.41 x 105 seconds of diffusion, the concentration of A in B was measured to be 0.270 g/rul, and the concentration of A in C was 0.0
At 0.0261 g/ml, the amount of A in C had increased to 0.767 g.

A diffusivity of 2.9 x 10 W/sec was obtained.

Temperature and pressure were at ambient conditions. Example 4 An extraction experiment was conducted by following the method of Example 1.

A 16.4 x 10-2 thick membrane A was used.

The effective diffusion area of the membrane was 16.75 cIIL.

Solute A is ε-caprolactam, liquid B is H2O, liquid C
was CHCl3.

Initially, the volume of B is 300 m11. C is 295.5ml
.

The amount of A in B is 81. The amount of A in l and C was O.

After 8.16 x 10' seconds of diffusion, the concentration of A in B was measured to be 0.261 g/rrtl, and the concentration of A in C was 0.261 g/rrtl.
0182g/rILl, and the amount of A in C is 5.38
It had risen to g.

A diffusion rate of 2.4×10 −7 sec cyrt/sec was obtained.

Temperature and pressure were at ambient conditions. Example 5 An extraction experiment was conducted by following the method of Example 1.

9. A film 5 having a thickness of 22×10′ crfL was used.

The membrane diffusion area was 16.75-.

Solute A is ε-caprolactam, liquid B is H2O1 liquid C
was CHCl3.

Initially, the volume of B is 29.6 m1. The volume of C is 296
The amount of A in m1.13 was 80 g, and the amount of C in m1.13 was O.

After 7.05 x 10' seconds of diffusion, the concentration of A in B was measured to be 0.197 g/ml, and the concentration in C was 0.0851 g/ml.
and the amount of A in C is 26.54. ! It rose to ii'.

A diffusivity of 9.22 x 10 W/sec was obtained. Temperature and pressure were at ambient conditions.

Example 6 An extraction experiment was conducted by following the method of Example 1.

A film 6 having a thickness of 2.48×10 −2 cIrL was used.

The effective diffusion area of the membrane was 20.78 CriL.

Solute A is ε-caprolactam, liquid B is H2O1 liquid C
was CHCl3.

Initially, the volume of B is 297.5ml, and the volume of C is 30ml.
1m1. The amount of A in B is 80.4g, and the amount of A in C is O
was.

After diffusion for 1.73 x 1O5 seconds, the concentration of A in B was measured to be 0.259 g/ml, and the concentration of A in C was 0.01.
42 g/ml, and the amount of A in C is 42. : It had risen to l.

A diffusivity of 1.11 x 10-■/sec was obtained.

Temperature and pressure were at ambient conditions.

Example 7 An extraction experiment was conducted by following the method of Example 1.

A 2.01×10 −2 thick membrane 7 was used.

The effective diffusion area of the membrane was 20.78 ci.

Solute A is ε-caprolactam, liquid B is H2O1 liquid C
was CHCl3.

Initially, the volume of B is 296 m1. The volume of C is 294.5
The amount of A in m11B was 80 g, and the amount of A in C was 0.

After 1.68 x 1O5 seconds of diffusion, the concentration of A in B is 0.24897.The concentration of A in TL11C is 0.028.
g/ml, and the amount of A in C had increased to 8.329.

A diffusivity of 1.87×10′ CIIL seconds was obtained.

Temperature and pressure were at ambient conditions. Example 8 An extraction experiment was conducted by following the method of Example 1.

A 2.26 x 10-'' thick membrane 8 was used.

The effective diffusion area of the membrane was 20.78-.

Solute A was ε-caprolactam, liquid B was It (20), and liquid C was CH (J'3).

Initially, the volume of B is 28977111 The volume of C is 303
m1. The amount of A in f3 is 78.1 g, and the amount of A in C
The amount was O.

After diffusion for 1.13 x 1O5 seconds, the concentration of A in B was measured to be 0.25 g/rnl, and the concentration of A in C was 0.02.
85 ji/rnl, and the amount of A in C is 8.39g
It was rising.

A diffusivity of 3.13×10 −■/sec was obtained.

Temperature and pressure were at ambient conditions.

Example 9 An extraction experiment was conducted by following the method of Example 1.

A film with a thickness of 7.9×10 −3 crfL was used.

The effective diffusion area of the membrane was 16.75i.

Solute A is ε-caprolactam, liquid B is H2O, liquid C
was CHCl3.

Initially, the volume of B was 299.5 rILl, the volume of C was 29577111, the amount of A in B was 81 g, and the amount of C in B was O.

7. After diffusion for 63 x 10' seconds, the concentration of A in B is measured to be 0.21,9/1rLl, and the concentration of A in C is 0.
．． 069297ml, and the amount of A in C is 21.1g
It was rising.

A diffusivity of 5.6×10 −■/sec was obtained.

Temperature and pressure were at ambient conditions. Example 10 An extraction experiment was conducted by following the method of Example 1.

A film with a thickness of 1.37×10 −2 CIrL was used.

The effective diffusion area of the membrane was 20.78 ffl.

Solute A is ε-caprolactam, liquid B is H2O1 liquid C
was CHCl3.

Initially, the volume of B is 331 m, the volume of C is 330 m,
The amount of A in B was 911 and the amount of A in C was O.

After 8.4 x 10' seconds of diffusion, the concentration of A in B was measured, and the concentration of A in B was 0.225 g/0.0755 in TL11C.
9/rrtl, and the amount of A in C had increased to 21 g.

A diffusivity of 8.83×10 −■/sec was obtained.

Temperature and pressure were at ambient conditions.

Example 11 An extraction experiment was conducted by following the method of Example 1.

A film 6 having a thickness of 2.48×10 −2 CrrL was used.

The effective diffusion area of the membrane was 20.78-.

Solute A is C2H4C12, liquid B is H2O1, liquid C is n
-It was heptane.

Initially, the volume of B is 292.5 m7. The volume of C is 29
The amount of A in B was 2.07 g, and the amount of A in C was O.

After diffusion for 2.43×1O5 seconds, the concentration of A in B was measured to be 0.0053 g/TLl, and the concentration in C was 0.001.
It was 78g/company, and the amount of A in C had increased to 052g.

A diffusion rate of 4.22 x 10-7 cr7t/sec was obtained.

Temperature and pressure were at ambient conditions. Example 12 An extraction experiment was conducted by following the method of Example 1.

A film 7 having a thickness of 2.01×1 O −2 crIL was used.

The effective diffusion area of the membrane was 20.78 cffl.

Solute A is C2H4C12, liquid B is H2O1, liquid C is n
-It was hebutane.

Initially, the volume of B is 295.5 ml, and the volume of C is 29
1.5 ml, the amount of A in B was 2.0'l, and the amount in C was O.

After 2.51 x 105 seconds of diffusion, the concentration of A in B was measured to be 0.00404. F/TLl, concentration in C is 0.00
309 j; i/ml, and the amount of A in C is 0.9 g
It was rising.

A diffusivity of 6.47 X 1 o-7d/sec was obtained.

Temperature and pressure were at ambient conditions. Example 13 An extraction experiment was conducted by following the method of Example 1.

A membrane 1 with a thickness of 7.9×10 −31 was used.

The effective diffusion m product of the membrane is 16.75 crj tattao, solute is 2H + cl) 2, liquid B is H2O, liquid C is n-
It was hebutane.

Initially, the volume of B is 302.51rLl, and the volume of C is 296rnl.

The amount of A in B was 2.14 g, and the amount of A in C was 0.

After diffusion for 8.95 x 10' seconds, the concentration of A in B was measured to be 0.00506 g/rnl, and the concentration of A in C was o
, o 0206 g/ml, and the amount of A in C is 0.
It had risen to 619.

The diffusivity of 537×10-7 sand was obtained.

Temperature and pressure were at ambient conditions. Example 14 An extraction experiment was conducted by following the method of Example 1.

A membrane 6 with a thickness of 2.48 x 100-2a was used.

The effective diffusion area of the membrane was 20.78-.

Solute A is dinitrotoluene, liquid B is toluene, liquid C
was H2O.

Initially, the volume of B is 2851n11The volume of C is 296m
1. The amount of A in hB was 56.8 g, and the amount of A in C was 0.

After 1.67 x 105 seconds of diffusion, the concentration of A in B was measured to be 0.1999/ml, and the concentration of A in C was 22.3.
X 10”g/rnl, and the amount of A in C is 0.00
The weight had increased to 66g.

3.16 Xl0-7CI! A diffusion rate of /sec was obtained.

Temperature and pressure were at ambient conditions.

Example 15 An extraction experiment was conducted by following the method of Example 1.

A membrane 7 having a thickness of 2.03×10 −2 crIL was used.

The effective diffusion area of the membrane was 20.78i.

Solute A is dinitrotoluene, liquid B is toluene, liquid C
was H2O.

Initially, the volume of B is 301 m11, and this volume is 298.
The amount of A in 577111B was 60 g, and the amount of A in C was 0.

After 1.73 x 105 seconds of diffusion, the concentration of A in B was measured to be 0.199 g/ml, and the concentration of A in C was 44.9
X10''!!/ml, and the amount of A in C is 0.013
It had increased to 4g.

A diffusivity of 6.06 x 10-7-7 seconds was obtained.

Temperature and pressure were at ambient conditions.

Example 16 An extraction experiment was conducted by following the method of Example 1.

A membrane 1 with a thickness of 7.9×10 −31 was used.

The effective diffusion area of the membrane was 16.75 CIL.

Solute A is dinitrotoluene, liquid B is toluene, liquid C
Is it H2O? , 4At the beginning, the volume of B is 293TLl,
The volume of C is 298m1. , the amount of A in B is 58.4g
, and the amount of A in C was O.

After 7.85 x 10' seconds of diffusion, the concentration of A in B was measured to be 0.199 g/ml, and the concentration of A in C was 27.3.
X10”f!/rrtl, and the amount of A in C is 0.
The weight had increased to 0.00814g.

A diffusivity of 5×10 −7 d/sec was obtained.

Temperature and pressure were at ambient conditions.

Example 17 An extraction experiment was conducted by following the method of Example 1.

A membrane 10 with a thickness of 1.88×10 −2 crIl was used.

The effective diffusion area of the membrane was 20.78 ci.

Solute A is dinitrotoluene, liquid B is toluene, liquid C
was H2O.

Initially, the volume of B is 293rn11C's volume is 300,
5 ml, the amount of A in B was 58.4 g, and the amount of A in C was 0.

After 1.03 x 105 seconds of diffusion, the concentration of A in B was measured to be 0.199 g/rul, and the concentration of A in C was 24.
3 x 10” El/ml, and the amount of A in C is 0
．． The weight had increased to 0,073g.

A diffusivity of 6.4 XI O-7-7 seconds was obtained.

Temperature and pressure were at ambient conditions.

Example 18 Following the method of Example 1, an extraction experiment was conducted.

A film 1 with a thickness of 7.9×10 −3 was used.

The effective diffusion area of the membrane was 16.75i.

Solute A was phenol, liquid B was H2O, and liquid C was toluene.

Initially, the volume of B is 295 m1. The volume of C is 291m1
．． ．． The amount of A in No. 13 was 11 g, and the amount of A in C was O.

8. After diffusion for 04 x 10' seconds, the concentration of A in B is 0.02
The concentration of A in 35g/m11C is 0.0141 g/r
The amount of A in C is 4.08. ! It was rising to i'.

A diffusivity of 9.7 x 10-7 crit/sec was obtained.

Temperature and pressure were at ambient conditions.

Example 19 An extraction experiment was conducted by following the method of Example 1.

A film 11 with a thickness of 1.3×10 −2 crrL was used.

The effective diffusion area of the membrane was 16.75 ffl.

Solute A was toluenediamine, liquid B was H2O, and liquid C was dinitrotoluene at 70°C.

Initially, the volume of B is 291 ml. The volume of C is 290T
The amount of A in l11B is 2.91. ! li'.

And the amount of A in C was 0.

i, s After 1xio 5 seconds of diffusion, the concentration of A in B is 0.004579/rue, and the concentration of A in C is 0.
．． 0054511/ml, and the amount of A in C is 1.5
It had risen to 8.9.

A diffusion rate of 1.06 x 10" cr't/sec was obtained.

The temperature was 70°C and the pressure was at ambient conditions.

Example 20 An extraction experiment was conducted by following the method of Example 1.

A film 7 with a thickness of 2.03 x 100-2 was used.

The effective diffusion area of the membrane was 20.78 ffl.

Solute A was toluenediamine, liquid B was H2O, and liquid C was dinitrotoluene at 70°C.

Initially, the volume of B is 290 ml. The volume of C is 2907
The amount of A in rL11B was 2.9 g, and the amount of A in C was O.

After 1.77 x 105 seconds of diffusion, the concentration of A in B is measured (the concentration of A in 100334g/77111C is 0.
00666 g/rul, and the amount of A in C is 1.9
．． It had risen to 1.

A diffusion rate of 2.05 x 10''-7 seconds was obtained.

The temperature was 70°C and the pressure was at ambient conditions.

Example 21 Boundary membrane countercurrent solvent extraction experiments were conducted using a hollow fiber extractor consisting of membrane 12.

The outer diameter, inner diameter and effective length of the extractor are 5. ICr
fL, 4.6crn, and 12.7crrL.

The extractor used consisted of 1.26 x 10' hollow fibers with dimensions of 230μ outer diameter and 180μ inner diameter.

Solute A was furfural, liquid B was H2O, and liquid C was toluene.

During this hollow fiber solvent extraction operation, the extractor was laid horizontally.

Liquid phase B with a flow rate of 0.948 g/sec was injected into the extractor on the outside of the hollow fiber, while liquid phase C with a flow rate of 0.821/sec was inside the hollow fiber.

The inflow concentration of A in B is 5.02%, and the outflow concentration is 1
．． It was 14%.

The inflow concentration of A in C is O, and the outflow concentration is 4.41%
was.

A diffusivity of 1.78 x 10-7 d/sec was obtained.

Temperature and pressure were at ambient conditions.

The membrane systems described above, along with other membrane systems, are listed in Table 1 along with their respective diffusivities.

In addition to membranes with the specific compositions mentioned above, membranes of the same type with different compositions and membranes such as cellulosic, polyethylene, polypropylene, polystyrene, etc. can be used in solvent film extraction.

Several commercially available hollow fibers, such as Dow hollow fiber (U.S. Pat. No. 3,228,876), DuPont's "Perm-ase"
p) “Hollow fiber [Chemical Engineering (Che
Mical Engineering), p. 54, 19
November 29, 1971], Amicon Inc., Diafiber (D
IAFIBER) hollow fibers, etc.

These hollow fibers are widely used in dialysis, hyperfiltration and repermeation fields.

In addition to the above embodiments, the membrane solvent extraction method of the present invention can be applied to the following systems which further illustrate, but do not limit, the present invention.

These systems are described using three columns A, B and C in Table m.

As mentioned above, A is a solute and B and C are two virtually immiscible liquids.

C is used as a liquid solvent to extract A from another liquid B in which A is dissolved, and can be used in reverse by exchanging B and C.

The application of the solvent film extraction of this invention is as follows. It is not limited to the systems listed in Table II and the Examples.

It is similarly applicable to other liquid-liquid extraction systems.

Various modifications apparent to those skilled in the art can be made without departing from the scope or spirit of this invention.

These modifications are within the scope of the invention except as excluded by the claims.

[Brief explanation of drawings]

FIG. 1 is an illustration of a hollow fiber arrangement, including reference to material flow for a typical extraction method. FIG. 2 is a cross-sectional view of a hollow fiber arrangement of the type shown in FIG. FIG. 3 is a typical flow diagram of an extraction method using the hollow fiber mechanism of the present invention. FIG. 4 is an illustration of an apparatus consisting of a multilayer membrane extraction unit arrangement in which various solutes are sequentially extracted. FIG. 5 is an illustration of an arrangement utilizing multiple membrane extractors in a membrane extraction unit.

Claims (1)

[Claims] 1 Bringing the first liquid containing solute A into contact with one side of the membrane,
a second liquid C for extraction which is virtually immiscible with liquid B;
in contact with the other side of the membrane, keeping liquids B and C separated by this membrane, and maintaining liquids B and C on each side of the iron membrane until solute A has completely diffused into liquid C. A solvent extraction method comprising the step of extracting solute A from liquid B to liquid C through a membrane.