Technique for preparing m-cresol

A preparation process and a technology for m-cresol, applied in the field of m-cresol preparation technology, can solve the problems of low recovery efficiency of m-cresol products, difficult treatment of tar-like substances, influence on reaction and product quality, etc., so as to reduce waste water treatment procedures. , the effect of short reaction period and fast desorption rate

Inactive Publication Date: 2008-02-20
ZHONGBEI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0024] In the above method, m-cresol mainly exists in the overflow liquid, and it is difficult to handle the tar-like substance.
Moreover, in the continuous production mode, since the diazonium salt is continuously added, the sodium salt in the waste acid is continuously increased, which not only affects the reaction and the yield of m-cresol due to the ion effect, but also brings difficulties to the maintenance of the equipment.
[0025] The macroporous adsorption resin that adopts in the above-mentioned method is XDA-1 type macroporous resin, because XDA-1 type macroporous resin has very strong adsorption to m-cresol, desorption is difficult, therefore, the recovery efficiency of m-cresol product is relatively high. Low
And when using the XDA-1 type macroporous adsorption resin to process the overflowed waste acid and reuse it in the salt-forming reaction of m-toluidine, the COD in the waste acid Cr On the contrary, it will increase, and it will be directly used in production, which will inevitably affect the reaction and product quality

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Add 180mL of 28% sulfuric acid solution into the salt-forming kettle, and add 21.6g of m-toluidine while stirring at room temperature to obtain an aqueous solution of m-toluidine sulfate.

[0049] Add the above m-toluidine sulfate aqueous solution into the diazotization reaction kettle with cooling device, lower the temperature to -3°C~0°C, slowly add 40mL of 35% sodium nitrite solution dropwise, and control the reaction to form m-toluidine Aniline diazosulfate until the starch potassium iodide test paper turns blue, add a small amount of urea after 10 to 15 minutes to remove excess sodium nitrite, until no bubbles escape, and the color of the solution is bright yellow.

[0050] Add 40mL of 40% sulfuric acid solution into the hydrolysis reaction kettle, preheat to 110°C, pass in water vapor, keep warm and control the temperature of the m-toluidine diazonium sulfate solution at -3°C to 0°C, and add it dropwise at a flow rate of 18mL / min to In the hydrolysis reaction kett...

Embodiment 2

[0056] Add 250mL of 30% sulfuric acid solution into the salt-forming kettle, and add 32.4g m-toluidine while stirring at room temperature to obtain an aqueous solution of m-toluidine sulfate.

[0057] Add the above-mentioned m-toluidine sulfate aqueous solution into a diazotization reaction kettle with a cooling device, lower the temperature to -3°C to 0°C, slowly add 62 mL of 35% sodium nitrite solution dropwise, and control the reaction to form m-toluidine Aniline diazosulfate until the starch potassium iodide test paper turns blue, add a small amount of urea after 10 to 15 minutes to remove excess sodium nitrite, until no bubbles escape, and the color of the solution is bright yellow.

[0058] Add 100mL of 45% sulfuric acid solution into the hydrolysis reaction kettle, preheat to 110°C, pass in water vapor, keep warm and control the temperature of m-toluidine diazonium sulfate solution at -3°C to 0°C, and add it dropwise at a flow rate of 25mL / min to In the hydrolysis react...

Embodiment 3

[0064] Add 347mL of 35% sulfuric acid solution into the salt-forming kettle, and add 50.0g m-toluidine while stirring at room temperature to obtain an aqueous solution of m-toluidine sulfate.

[0065] Add the above-mentioned m-toluidine sulfate aqueous solution into the diazotization reaction kettle with a cooling device, lower the temperature to -3°C to 0°C, slowly add 94mL of 35% sodium nitrite solution dropwise, and control the reaction to form m-toluidine Aniline diazosulfate until the starch potassium iodide test paper turns blue, add a small amount of urea after 10 to 15 minutes to remove excess sodium nitrite, until no bubbles escape, and the color of the solution is bright yellow.

[0066] Add 80mL of 45% sulfuric acid solution into the hydrolysis reaction kettle, preheat to 110°C, feed water vapor, keep warm and control the temperature of the m-toluidine diazonium sulfate solution at -3°C to 0°C, and add it dropwise at a flow rate of 20mL / min to In the hydrolysis reac...

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PUM

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Abstract

A preparation technical of m-cresol is that: M-cresol is diazotizated, and hydrolyzed while at the same time steam is distilled to prepare a distilled m-cresol hydrolysis liquid. The distilled hydrolysis liquid passes through a N3520 type macroporous resin, and is eluded by organic solvent; the m-cresol product is obtained after rectifying. The invention adopts steam to distil m-cresol generated by hydrolyzation in time, which produces little byproduct tarry matter and increases the yield rate of m-cresol; preparation of product and treatment of waste water are carried out at the same time, which reduces the waste water treatment procedure and simplify the progress of preparation technology; because the invention adopts N3520 type macroporous resin to dispose the distilled m-cresol hydrolysis liquid, the m-cresol is easily desorbed with a fast desorption rate and a short reaction cycle, thus being beneficial to the recycle of m-cresol. The preparation technology of m-cresol of the invention has a yield rate over 85 percent and purity over 99.5 percent.

Description

technical field [0001] The invention belongs to the field of fine chemical manufacturing, and in particular relates to a preparation process of m-cresol. Background technique [0002] There are three isomers of cresol, namely o-cresol, m-cresol and p-cresol, all of which are important chemical raw materials. The chemical name of m-cresol is 3-hydroxytoluene, and the molecular formula is C 7 h 8 O, is a colorless to light yellow flammable liquid with phenol smell, it can be used in industries such as medicine, pesticide, dye, spice, resin, plasticizer, film, antioxidant and reagent, mainly used in synthesis speed Dicarb, fenthion, antioxidant CA, tribromocresol, 4-nitro-m-cresol, 3-phenoxytoluene, m-cresol, m-methyldiphenylaldehyde, calcium cresylsulfonate , Disperse Yellow SE-5R, chlorocresol m-cresyl ester, 2-chloro-5-cresol, 4-chloro-3-cresol, m-hydroxybenzaldehyde and other chemical raw materials and products. [0003] The current m-cresol preparation process mainly c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/07C07C37/05
Inventor 曹端林崔建兰郑志花赵林秀吕春绪陆明
Owner ZHONGBEI UNIV
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