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Method for preparing 2,6-dichlorotoluene employing Hbeta molecular sieve and catalytic o-chlorotoluene

A technology for catalyzing ortho- and dichlorotoluene by molecular sieve is applied in chemical instruments and methods, preparation of halogenated hydrocarbons, organic chemistry, etc., and can solve the problems of difficult to realize industrialization, slow chlorination reaction speed, complicated reaction conditions, etc., and achieve easy product The effect of separation, simple operation and simple reaction steps

Inactive Publication Date: 2015-09-02
NANJING ZHONGTENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the reaction conditions of the above two methods are complicated, the yield is low, and the pollution is serious; 3 It is prepared by catalyzing thionyl chloride chlorination and then dealkylation; the chlorination reaction speed of this method is slow, and the temperature required for dealkylation is relatively high; the above four methods are complicated to operate, the reaction conditions are harsh, separation is difficult, and it is not easy to realize industrialization

Method used

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  • Method for preparing 2,6-dichlorotoluene employing Hbeta molecular sieve and catalytic o-chlorotoluene
  • Method for preparing 2,6-dichlorotoluene employing Hbeta molecular sieve and catalytic o-chlorotoluene
  • Method for preparing 2,6-dichlorotoluene employing Hbeta molecular sieve and catalytic o-chlorotoluene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] (1) Preparation of Hβ molecular sieve: 5 g β molecular sieve and 50 mL NH 4 NO 3 The solution was added into a 100 mL three-necked flask, stirred at 90 °C for 1 h, filtered and washed, and the obtained sample was dried in an oven at 120 °C for 2 h. Calcined at 500 °C for 2 h in a muffle furnace to obtain Hβ molecular sieves.

[0028] (2) Chlorination reaction step of o-chlorotoluene Add 141 mL (150 g) of o-chlorotoluene into a 250 mL four-neck flask, add 3.0 g of Hβ molecular sieve catalyst, stir to disperse evenly; then pass 50 mL / Min chlorine gas dried with concentrated sulfuric acid, reacted at 35 °C for 12 h to obtain dichlorotoluene, after the tail gas was condensed, it was absorbed by NaOH solution to remove unreacted Cl 2 .

[0029] Change the amount of Hβ molecular sieve to 1.5 g, 7.5 g, the influence of the amount of Hβ molecular sieve catalyst on the chlorination process of o-chlorotoluene can be obtained as shown in Table 1:

[0030] Table 1 Effe...

Embodiment 2

[0036] The same method as in Example 1 is used to prepare the Hβ molecular sieve catalyst. The chlorination process of o-chlorotoluene adopts the same method as in Example 1, but the reaction time is changed to 3 h, 6 h, and 9 h to obtain different reaction times for o-chlorotoluene chloride. The impact of the chemical process, as shown in Table 2:

[0037] Table 2 Effects of different reaction times on the chlorination of o-chlorotoluene

[0038]

[0039] Table 2 reflects the impact of reaction time on the chlorination of o-chlorotoluene; as can be seen from the table, as the reaction time is extended from 3 h to 12 h, the conversion rate of o-chlorotoluene increases from 10.36% to 67.72%; 2 , the selectivity of 6-DCT gradually decreased from 34.36% to 30.45%.

[0040] The experimental results show that prolonging the reaction time is conducive to the improvement of the conversion rate of o-chlorotoluene and the increase of the selectivity of by-products, which will l...

Embodiment 3

[0042] Adopt the same method of embodiment 1 to prepare Hβ molecular sieve catalyst, adopt the same method of embodiment 1 in the o-chlorotoluene chlorination process, but change reaction temperature to be 50 ℃, 65 ℃, can obtain different reaction temperatures to the o-chlorotoluene chlorination process Impact, as shown in Table 3:

[0043] Table 3 Effects of different reaction temperatures on the chlorination of o-chlorotoluene

[0044]

[0045] Table 3 reflects the impact of reaction temperature on the chlorination of o-chlorotoluene; as can be seen from Table 3, as the reaction temperature increases from 35 °C to 65 °C, the conversion of o-chlorotoluene increases from 67.72% to 90.15%; The selectivity of 2,6-DCT decreased from 30.45% to 26.81%; this indicates that low temperature is beneficial to the increase of the selectivity of 2,6-DCT, but it also inhibits the conversion rate of o-chlorotoluene.

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Abstract

The invention relates to the technical field of 2,6-dichlorotoluene preparation, in particular to a method for preparing 2,6-dichlorotoluene employing selective chlorination of an Hbeta molecular sieve and catalytic o-chlorotoluene. With cheap o-chlorotoluene as a raw material, a chlorine gas as a chlorinating agent and the Hbeta molecular sieve as a catalyst, the 2,6-dichlorotoluene is prepared by selective chlorination of the catalytic o-chlorotoluene employing a one-step chlorination method. The method is easy to operate, simple in steps, relatively low in production cost and easy to industrialize.

Description

technical field [0001] The invention relates to the technical field of 2,6-dichlorotoluene preparation, in particular to a method for preparing 2,6-dichlorotoluene by selective chlorination of o-chlorotoluene catalyzed by Hβ molecular sieves. Background technique [0002] 2,6-dichlorotoluene, as an important fine chemical raw material, is widely used in various aspects such as pesticides, dyes, and medicines. In recent years, it has attracted more and more attention. At present, there is no large-scale production in China and it mainly relies on imports. Seriously restricting the development and research of downstream products. [0003] At present, the synthesis methods of 2,6-dichlorotoluene mainly include the following types: (1) It is obtained by chlorination and separation of toluene as raw material. However, there are 6 isomers generated by this method, which are difficult to separate; (2) It is prepared by chlorination, reduction, and diazotization reactions using o-...

Claims

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Application Information

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IPC IPC(8): C07C17/12C07C25/02
Inventor 朱晓燕殷恒波沈灵沁王爱丽付玉军侯祥祥
Owner NANJING ZHONGTENG CHEM
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