JPS58131922A - Separation of chlorobenzotrifluoride isomers - Google Patents

Abstract

PURPOSE:A specific zeolite adsorbent containing cations selected from groups IA and others in the periodic table is used to separate m-chlorobenzotrifluoride useful as an intermediate of drugs from a mixture containing m- and p-chlorobenzotrifluorides. CONSTITUTION:A faujacite type zeolite adsobent containig at least one cation selected from groups IA, IB and IIA in the periodic tables (particularly preferable cations are Na, Ag, K and Ba) is used to effect selective adsorption of m- chlorobenzotrifluoride from a mixture thereof with p-chlorobenzotrifluoride and the remaining p-chlorobenzotrifluoride is recovered as a raffinate together with the desorption agent. The adsoption is conducted at room temperature to 350 deg.C, preferably 50-250 deg.C and atmosheric pressure to 40kg/cm<2>.G.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to chlorobencitrifluoride (hereinafter referred to as Cl −
This invention relates to a method for adsorption and separation of isomers (BTFh for short), and relates to a method for separating isomers by selectively forming an a-layer.

Cl-111"F is known as an important intermediate raw material for agricultural chemicals and medicines. Among these, m-C1-HI"F is commercially produced using the nuclear chlorination reaction of pencitrifluoride. There is. Since the nuclear chlorination reaction of pensitrifluoride is meta-coordinating, m-C1-WFt- is mainly produced, but some p- and 0-C1-HI”F
as a by-product. Of these, the boiling point of the O-isomer is about 10°C higher than that of the m-isomer, so it can be separated by rectification relatively easily, but the p-isomer has a boiling point difference with the middle-isomer. is as small as about 10, making rectification separation very difficult.

Therefore, in order to obtain highly pure w-CI-WF, ultra-precision distillation equipment with a high number of stages is required, and the amount of utility used is large, which is not economical.

Therefore, as a result of intensive research into a method for efficiently separating a mixture containing tn-C1-m''F and p-C1-m''F, the present inventors found that in a specific zeolite adsorbent, tn-C1-m''F
-m'l' was found to be selectively adsorbed, and the present invention was achieved.

That is, the present invention applies to Groups 1A and 1B of the periodic table of elements.
At least one member selected from the group consisting of Group mA and Group mA.
It is characterized by selectively adsorbing and separating m-Cl-IH'F from a mixture containing l- and p-C1-gl'Fk using a faujasite-type zeolite thread adsorbent containing seed cations. The present invention provides a method for separating the C1-m''F isomer.

The 7-odiasite type zeolite used in the method of the present invention is a crystalline aluminosilicate represented by the following formula.

0.9 ±0.2 M2AL O2Al 20. 2Z
Si02:WB,0 where M represents a cation and n
h Expressed on its valence. The faujasite type zeolite of the above formula is further classified into X and Y types, and the X type has z = 2
．． 5±0.5, and the Y type is represented by z = 3 to 6. It depends on the level of water availability.

The faujasite-type zeolites used in the method of the present invention are group 1A, group 1B and group 1, zeolite of the periodic table.
It essentially contains at least one cation selected from the group consisting of Group 4, and among these, a particularly preferred cation is Na.

AQ, K, Bα, and Na cations are particularly preferred.

Ion-exchange methods for these cations are well known to those skilled in the art having knowledge of the production of crystalline aluminosilicates, and are usually carried out in an aqueous solution of 1m or more of the soluble salt of the cation to be added. This can be carried out by contacting a jasite type zeolite.

The adsorption separation technology for adsorption separation of the C1-HI'F isomer mixture using the adsorbent of the present invention may be a so-called chromatographic separation method, or adsorption separation using a continuous pseudo-mobile. It may be a method.

The continuous adsorption/separation wave j#u using a simulated moving bed is carried out by continuously cycling the following basic operations: adsorption operation, concentration operation, and desorption operation.

(1) Inhalation operation two- and p-C1-m'F'? When the raw material mixture containing m-CI-E is contacted with the adsorbent of the present invention,
TF is selectively adsorbed. The remaining p-C1-BTF is recovered as a raffinate together with a desorbent to be described later.

(2) Concentration operation: tn-CI-KrF % - The selectively adsorbed adsorbent is brought into contact with a portion of the extract, which will be described later, and p-c is non-selectively adsorbed onto the adsorbent.
The t-mγ is expelled and the normal-ct-m force is highly purified.

(3) Desorption operation: Highly purified f? :, m-C1-BT
F is expelled from the adsorbent by the desorbent and collected as an extract together with the desorbent.

As the desorbent used in the above adsorption separation method or the developing agent used in chromatographic separation, compounds that can be easily separated by distillation, such as ct-gr, are used. Hydrogen is preferred;
Particularly preferred are toluene, chlorotoluene, dichlorotoluene, trichlorobenzene, chloroxylene, pencitrifluoride, dichlorobencitrifluoride, and the like.

The operating conditions for the adsorption separation method include temperatures ranging from room temperature to 35°C.
0℃, preferably #i 50 to 250℃, the pressure is 4/cj・G, preferably 40 to 50 from atmospheric pressure
Kt/ffl・G. The adsorption separation process of the present invention can be carried out in either the gas or liquid phase, and is preferably carried out in the liquid phase in order to reduce the tζ operating temperature and suppress undesirable side reactions of the feedstock or desorbent.

Next, the method of the present invention will be explained with reference to Example t. In the examples, the absorption y#% of the adsorbent is expressed by the adsorption selectivity (α) of the following formula.

Here, A indicates an adsorption phase and U indicates a liquid phase in equilibrium with the adsorption phase.

The adsorbent whose α value in the above formula is greater than l is m-C1-ET.
Suitable for selective adsorption separation of F.

Example l.

Nα-YC3sO2/At203=4.8) type zeolite powder (manufactured by Union Carbide, 5K-40>, and alumina sol t-Al as a binder, O, converted to 10
A granulated product of 24 to 32 meshes is obtained by extrusion molding with wt dovetailing. After drying this granulated product at 1100°C, the activated adsorbent 2f and liquid phase mixture were calcined for about 1 hour at 1100°C and 2t
’ in an autoclave with an internal volume of 5 d and heated to 130°C.
I left it for 1 hour. The composition of the charged liquid phase mixture is vr
-)-J-n: tx-C1-1fl”F:p-CI
-gl''F = 1:l:1 (weight ratio).

Nonane was added as a marker substance in gas chromatography analysis, and is a substance that is substantially inert to the adsorbent under the above experimental conditions. The adsorption selectivity α was determined by analyzing the composition of the liquid phase mixture after contact with the adsorbent using the equation L (1).

The results are shown in Table 1.

Example 2 Nα-Y zeolite with 5so2/Ax 203 = 3.2 and Nα-X zeolide adsorbent with 2.5 Measurements were carried out in the same manner as in all Examples.

The results are shown in Table 1.

Example 3゜The adsorbent f of Examples 1 and 2 was subjected to ion exchange treatment 5 times at a solid-liquid ratio of 5 using a 5 wt % potassium nitrate water bath solution to prepare a type faujasite, dried in the same manner as in Example 1, After firing, the suction selectivity II was measured. The results are shown in Table 1.

Example 4゜ fcK -Y C3iO,/Al 2 prepared in Example 3
0. = 4.8) type zeolite tK cation 30
It was treated with an aqueous solution of silver #R corresponding to mol- to prepare -YWf&adhesive t- to Ag-. After drying and baking in the same manner as in Example 1, the adsorption selectivity was measured. Table 1 shows the results.
Shown below.

Example 5゜K −X C3iO,/At 20 prepared in Example 3
．． = 2.5) type zeolite has about 80 cations
-Bα- is ion-exchanged so that - becomes Ba cation.
X-type adsorbent '1vI4 was manufactured. After drying and baking in the same manner as in Example 1, the adsorption selectivity was measured. Table 1 shows the results.
Shown below.

Table 1

Claims (1)

[Claims] Using a faujasite-type zeolite adsorbent containing at least one cation selected from the group consisting of Groups 1A, 2B, and 1A of the Periodic Table of the Elements, m- and p-chlorobencitrifluoride A method for separating pensitrifluoride isomers by selectively adsorbing and separating pensitrifluoride from a mixture containing pensitrifluoride.