Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a process for removing the o (p) chlorobenzyl alcohol impurity in the o (p) chlorobenzaldehyde product, which solves the problems of insufficient purity and poor product quality of the o (p) chlorobenzaldehyde caused by the existence of the o (p) chlorobenzyl alcohol impurity in the prior art.
According to an embodiment of the present invention, the present invention provides a process for removing o (p) chlorobenzyl alcohol as an impurity in an o (p) chlorobenzaldehyde product, comprising the steps of:
Hydrolysis reaction:
pumping the refined dichlorobenzyl crude product from a rectifying tower kettle liquid tank to a dichlorobenzyl overhead tank, putting the dichlorobenzyl overhead tank into a hydrolysis kettle through feeding, adding a catalyst with the mass fraction of 0.15% -0.3%, starting stirring, opening condenser cooling water, heating to 120-130 ℃, opening a water overhead tank outlet valve, continuously metering and dropwise adding water, stopping hydrolysis when the dichlorobenzyl content is less than or equal to 0.2%, and cooling to not higher than 80 ℃;
conversion reaction:
Quantitatively adding the prepared Rucas reagent into an o (p) chlorobenzaldehyde hydrolysate product according to the mol ratio of the Rucas reagent to the o (p) chlorobenzyl alcohol of 1:1, stirring at 80-100 ℃, carrying out heat preservation reaction for 3-5 hours, sampling and analyzing, ending the conversion reaction when the o (p) chlorobenzyl alcohol is less than or equal to 0.20%, and separating an o (p) chlorobenzaldehyde oil phase;
And (3) alkaline hydrolysis reaction:
Adding sodium carbonate solution and triethylamine into o (p) chlorobenzaldehyde oil phase obtained by conversion reaction, controlling the reaction temperature to be 90-100 ℃, carrying out reflux reaction under stirring, sampling and analyzing after the reaction is carried out for 4-6 hours, ending the alkaline hydrolysis reaction when o (p) chlorobenzyl chloride is less than or equal to 0.20%, separating o (p) chlorobenzaldehyde oil phase after the reaction is finished, and carrying out reduced pressure distillation on the oil phase to obtain an o (p) chlorobenzaldehyde finished product.
Preferably, in the hydrolysis reaction, the catalyst used is zinc oxide.
Preferably, in the hydrolysis reaction, sampling analysis is carried out after the reaction is finished, when the content of o (p) chlorobenzyl alcohol as an impurity in an o (p) chlorobenzaldehyde hydrolysate product is more than or equal to 0.2%, the next conversion reaction is carried out, and otherwise, reduced pressure distillation treatment is directly carried out.
Preferably, the conversion reaction and the alkaline hydrolysis reaction are carried out after being completed, water washing separation is carried out, excessive water is added into the product, the mixture is stirred and washed for 30-45 minutes, the mixture is kept stand for not less than 1 hour, and after oil-water delamination, the oil phase is extracted, so that o (p) chlorobenzaldehyde is separated out, and the next process is carried out.
Preferably, after the alkaline hydrolysis reaction, the separated water phase is sent to a sewage treatment workshop, and o (p) chlorobenzoic acid is recovered through acid separation and centrifugation.
Preferably, in the alkaline hydrolysis reaction, after the o (p) chlorobenzaldehyde oil phase is separated, the oil phase is subjected to secondary water washing separation, and then reduced pressure distillation is performed.
Preferably, in the alkaline hydrolysis reaction, the added sodium carbonate solution is 15-20% of sodium carbonate solution by weight percent.
The invention has the technical principle that the impurity o (p) chlorobenzyl alcohol in o (p) chlorobenzaldehyde products is converted into o (p) chlorobenzyl chloride by using a Rucass reagent, then a catalyst triethylamine is added in an alkaline hydrolysis process to complex the o (p) chlorobenzyl chloride into quaternary ammonium salt dissolved in water, the impurity is converted into a component dissolved in water, the impurity can be removed through oil-water separation, and finally the purification of the o (p) chlorobenzaldehyde products is realized through reduced pressure distillation.
Wherein the corresponding chemical reaction principle equation is as follows:
C6H4Cl—CH2OH+ZnCl2(HCl)＝C6H4Cl—CH2Cl+H2O
(o-chlorobenzyl alcohol) + (rukas reagent) = (o-chlorobenzyl chloride)
C6H4Cl—CH2Cl+N(CH2CH3)3＝C6H4Cl—CH2N(CH2CH3)3Cl
(O-chlorobenzyl) + (triethylamine) = (benzyl triethyl ammonium chloride)
Compared with the prior art, the invention has the following beneficial effects:
1. According to the invention, the steps of conversion reaction and alkaline hydrolysis reaction are added after the traditional o (p) chlorobenzaldehyde hydrolysis preparation process, the o (p) chlorobenzyl alcohol impurity in the o (p) chlorobenzaldehyde product is converted into o (p) chlorobenzyl chloride by using a Rucas reagent, then alkaline hydrolysis reaction is utilized, and the o (p) chlorobenzyl chloride is complexed into water-soluble quaternary ammonium salt by using triethylamine under an alkaline environment, so that the process of converting fat-soluble impurity components into water-soluble components is realized, then the impurities can be removed through oil-water separation, and finally, the purification and purification of the o (p) chlorobenzaldehyde product are realized through reduced pressure distillation, thereby greatly improving the purity of the prepared o (p) chlorobenzaldehyde product and obtaining high-quality product;
2. The alkaline hydrolysis reaction carried out in the invention can also react o (p) chlorobenzoic acid into o (p) chlorobenzoic acid, and the o (p) chlorobenzoic acid is also a water-soluble component, so that a small amount of o (p) chlorobenzoic acid impurities generated by oxidation of o (p) chlorobenzaldehyde in the reaction process are removed together, the product purity is further improved, and meanwhile, the generated o (p) chlorobenzoic acid is recovered, the raw material consumption is reduced, and the economic benefit is improved.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings and examples.
Example 1:
the embodiment comprises the following steps:
Hydrolysis reaction:
Extracting the refined dichlorobenzyl crude product from a rectifying tower kettle liquid tank to a dichlorobenzyl overhead tank, putting the dichlorobenzyl overhead tank into a hydrolysis kettle through feeding, adding 0.15 wt% of zinc oxide serving as a catalyst, starting stirring, opening condenser cooling water, heating to 120-130 ℃, opening a water overhead tank outlet valve, continuously metering and dropwise adding water, stopping hydrolysis when the dichlorobenzyl content is less than or equal to 0.2%, cooling to not higher than 80 ℃, sampling and analyzing after the reaction is finished, and turning into a next conversion reaction when the impurity o-chlorobenzyl alcohol content in an o-chlorobenzaldehyde hydrolysate product is not less than 0.2%, otherwise, directly performing reduced pressure distillation treatment on the qualified product.
3.6 Tons of off-specification o-chlorobenzaldehyde are detected together, wherein the content of o-chlorobenzyl alcohol is 0.50% wt.
Conversion reaction:
A rukas reagent was prepared by mixing 150 kg of zinc chloride with 130 kg of 30% hydrochloric acid.
And (3) adding the Rukas reagent into an o-chlorobenzaldehyde hydrolysate product, stirring at the temperature of 80-100 ℃, carrying out heat preservation reaction for 3 hours, sampling and analyzing, ending the conversion reaction when the o-chlorobenzyl alcohol is less than or equal to 0.20%, and separating an o-chlorobenzaldehyde oil phase. And (3) after the reaction is finished, carrying out water washing separation, adding 1 ton of water into the product, stirring and washing for 30 minutes, standing for 1 hour, and after oil-water delamination, extracting an oil phase to separate o-chlorobenzaldehyde and then entering the next process.
The o-chlorobenzyl alcohol content was found to be 0.12% by weight by sampling analysis.
And (3) alkaline hydrolysis reaction:
200 kg of sodium carbonate is added with water to prepare a 15% aqueous solution (PH=8-9).
And quantitatively adding sodium carbonate solution and 7kg of triethylamine into the o-chlorobenzaldehyde oil phase obtained by the conversion reaction, controlling the reaction temperature to be 90-100 ℃, carrying out reflux reaction under stirring, sampling and analyzing after the reaction is carried out for 4 hours, and ending the alkaline hydrolysis reaction when the o-chlorobenzyl chloride content is less than or equal to 0.20 percent.
The sample was analyzed to determine that the o-chlorobenzyl chloride content was 0.10% wt.
And (3) separating and purifying:
And (3) washing and separating after the reaction is finished, adding 1 ton of water into the product, stirring and washing for 30 minutes, standing for 1 hour, extracting an oil phase after oil-water delamination, separating o-chlorobenzaldehyde, carrying out secondary washing and separating on the oil phase in the same way, and carrying out reduced pressure distillation on the oil phase to obtain an o-chlorobenzaldehyde finished product. The separated water phase is sent to a sewage treatment workshop, and o-chlorobenzoic acid is recovered through acid separation and centrifugation.
The purity of the finally prepared o-chlorobenzaldehyde product is 99.75%.
Example 2:
the embodiment comprises the following steps:
Hydrolysis reaction:
extracting the refined dichlorobenzyl crude product from a rectifying tower kettle liquid tank to a dichlorobenzyl overhead tank, putting the dichlorobenzyl overhead tank into a hydrolysis kettle through feeding, adding 0.2% zinc oxide as a catalyst, starting stirring, opening condenser cooling water, heating to 120-130 ℃, opening a water overhead tank outlet valve, continuously metering and dropwise adding water, stopping hydrolysis when the dichlorobenzyl content is less than or equal to 0.2%, cooling to not higher than 80 ℃, sampling and analyzing after the reaction is finished, and turning into a next conversion reaction as an unqualified product when the impurity o-chlorobenzyl alcohol content in an o-chlorobenzaldehyde hydrolysate product is not less than 0.2%, otherwise directly performing reduced pressure distillation treatment as a qualified product.
3.6 Tons of off-specification o-chlorobenzaldehyde are detected together, wherein the content of o-chlorobenzyl alcohol is 0.75% wt.
Conversion reaction:
A rukas reagent was prepared by mixing 150 kg of zinc chloride with 130 kg of 30% hydrochloric acid.
And (3) adding the Rukas reagent into an o-chlorobenzaldehyde hydrolysate product, stirring at the temperature of 80-100 ℃, carrying out heat preservation reaction for 4 hours, sampling and analyzing, ending the conversion reaction when the o-chlorobenzyl alcohol is less than or equal to 0.20%, and separating an o-chlorobenzaldehyde oil phase. And (3) after the reaction is finished, carrying out water washing separation, adding 1 ton of water into the product, stirring and washing for 35 minutes, standing for 1.5 hours, and extracting an oil phase after oil-water delamination so as to separate o-chlorobenzaldehyde and then entering the next process.
The o-chlorobenzyl alcohol content was found to be 0.15% by weight by sampling analysis.
And (3) alkaline hydrolysis reaction:
200 kg of sodium carbonate is added with water to prepare an 18% aqueous solution (PH=9-11).
And quantitatively adding sodium carbonate solution and 7kg of triethylamine into the o-chlorobenzaldehyde oil phase obtained by the conversion reaction, controlling the reaction temperature to be 90-100 ℃, carrying out reflux reaction under stirring, sampling and analyzing after the reaction is carried out for 5 hours, and ending the alkaline hydrolysis reaction when the o-chlorobenzyl chloride content is less than or equal to 0.20 percent.
The sample was analyzed to determine that the o-chlorobenzyl chloride content was 0.10% wt.
And (3) separating and purifying:
And (3) washing and separating after the reaction is finished, adding 1 ton of water into the product, stirring and washing for 35 minutes, standing for 1.5 hours, extracting an oil phase after oil-water delamination, separating o-chlorobenzaldehyde, carrying out secondary washing and separating on the oil phase, and carrying out reduced pressure distillation on the oil phase to obtain an o-chlorobenzaldehyde finished product. The separated water phase is sent to a sewage treatment workshop, and o-chlorobenzoic acid is recovered through acid separation and centrifugation.
The purity of the finally prepared o-chlorobenzaldehyde product is 99.60 percent.
Example 3:
the embodiment comprises the following steps:
Hydrolysis reaction:
Extracting the refined dichlorobenzyl crude product from a rectifying tower kettle liquid tank to a dichlorobenzyl overhead tank, putting the dichlorobenzyl overhead tank into a hydrolysis kettle through feeding, adding 0.3% zinc oxide as a catalyst, starting stirring, opening condenser cooling water, heating to 120-130 ℃, opening a water overhead tank outlet valve, continuously metering and dropwise adding water, stopping hydrolysis when the dichlorobenzyl content is less than or equal to 0.2%, cooling to not higher than 80 ℃, sampling and analyzing after the reaction is finished, and turning into a next conversion reaction as an unqualified product when the content of the p-chlorobenzyl alcohol in the p-chlorobenzaldehyde hydrolysate product is not less than 0.2%, otherwise, directly performing reduced pressure distillation treatment as a qualified product.
3.5 Tons of off-specification p-chlorobenzaldehyde were co-detected, with a p-chlorobenzyl alcohol content of 0.60% by weight.
Conversion reaction:
A rukas reagent was prepared by mixing 150 kg of zinc chloride with 130 kg of 30% hydrochloric acid.
And (3) adding the Rukas reagent into the p-chlorobenzaldehyde hydrolysate product, stirring at the temperature of 80-100 ℃, carrying out heat preservation reaction for 5 hours, sampling and analyzing, ending the conversion reaction when the p-chlorobenzyl alcohol is less than or equal to 0.20%, and separating the p-chlorobenzaldehyde oil phase. And (3) after the reaction is finished, carrying out water washing separation, adding 1 ton of water into the product, stirring and washing for 45 minutes, standing for 1 hour, and after oil-water delamination, extracting an oil phase to separate p-chlorobenzaldehyde and carrying out the next process.
The analysis was sampled and the content of p-chlorobenzyl alcohol was 0.10% by weight.
And (3) alkaline hydrolysis reaction:
200 kg of sodium carbonate is added with water to prepare a 20% aqueous solution (PH=10-12).
And quantitatively adding sodium carbonate solution and 7kg of triethylamine into the p-chlorobenzaldehyde oil phase obtained by the conversion reaction, controlling the reaction temperature to be 90-100 ℃, carrying out reflux reaction under stirring, sampling and analyzing after the reaction is carried out for 6 hours, and ending the alkaline hydrolysis reaction when the p-chlorobenzyl chloride content is less than or equal to 0.20 percent.
The analysis by sampling was carried out with a content of p-chlorobenzyl chloride of 0.08% by weight.
And (3) separating and purifying:
And (3) washing and separating after the reaction is finished, adding 1 ton of water into the product, stirring and washing for 45 minutes, standing for 1 hour, extracting an oil phase after oil-water delamination, separating p-chlorobenzaldehyde, carrying out secondary washing and separating on the oil phase, and carrying out reduced pressure distillation on the oil phase to obtain a p-chlorobenzaldehyde finished product. The separated water phase is sent to a sewage treatment workshop, and p-chlorobenzoic acid is recovered through acid precipitation and centrifugation.
The purity of the finally prepared p-chlorobenzaldehyde product is 99.70%.
Example 4:
the embodiment comprises the following steps:
Hydrolysis reaction:
extracting the refined dichlorobenzyl crude product from a rectifying tower kettle liquid tank to a dichlorobenzyl overhead tank, putting the dichlorobenzyl overhead tank into a hydrolysis kettle through feeding, adding 0.15% zinc oxide as a catalyst, starting stirring, opening condenser cooling water, heating to 120-130 ℃, opening a water overhead tank outlet valve, continuously metering and dropwise adding water, stopping hydrolysis when the dichlorobenzyl content is less than or equal to 0.2%, cooling to not higher than 80 ℃, sampling and analyzing after the reaction is finished, and turning into a next conversion reaction as an unqualified product when the content of the p-chlorobenzyl alcohol in the p-chlorobenzaldehyde hydrolysate product is not less than 0.2%, otherwise, directly performing reduced pressure distillation treatment as a qualified product.
3.6 Tons of off-specification p-chlorobenzaldehyde were co-detected, with a p-chlorobenzyl alcohol content of 1.0% by weight.
Conversion reaction:
A rukas reagent was prepared by mixing 150 kg of zinc chloride with 130 kg of 30% hydrochloric acid.
And (3) adding the Rukas reagent into the p-chlorobenzaldehyde hydrolysate product, stirring at the temperature of 80-100 ℃, carrying out heat preservation reaction for 4 hours, sampling and analyzing, ending the conversion reaction when the p-chlorobenzyl alcohol is less than or equal to 0.20%, and separating the p-chlorobenzaldehyde oil phase. And (3) after the reaction is finished, carrying out water washing separation, adding 1 ton of water into the product, stirring and washing for 30 minutes, standing for 1 hour, and after oil-water delamination, extracting an oil phase to separate p-chlorobenzaldehyde and carrying out the next process.
The analysis was sampled and the content of p-chlorobenzyl alcohol was 0.10% by weight.
And (3) alkaline hydrolysis reaction:
200 kg of sodium carbonate is added with water to prepare a 15% aqueous solution (PH=8-9).
And quantitatively adding sodium carbonate solution and 7kg of triethylamine into the p-chlorobenzaldehyde oil phase obtained by the conversion reaction, controlling the reaction temperature to be 90-100 ℃, carrying out reflux reaction under stirring, sampling and analyzing after the reaction is carried out for 4 hours, and ending the alkaline hydrolysis reaction when the p-chlorobenzyl chloride is less than or equal to 0.20 percent.
The analysis by sampling was carried out with a content of p-chlorobenzyl chloride of 0.10% by weight.
And (3) separating and purifying:
And (3) washing and separating after the reaction is finished, adding 1 ton of water into the product, stirring and washing for 30 minutes, standing for 1 hour, extracting an oil phase after oil-water delamination, separating p-chlorobenzaldehyde, carrying out secondary washing and separating on the oil phase, and carrying out reduced pressure distillation on the oil phase to obtain a p-chlorobenzaldehyde finished product. The separated water phase is sent to a sewage treatment workshop, and p-chlorobenzoic acid is recovered through acid precipitation and centrifugation.
The purity of the finally prepared p-chlorobenzaldehyde product is 99.65%.
The parameters of the prepared products of the above examples are shown in table 1:
TABLE 1
As is clear from the background art, the purity of the o (p) chlorobenzaldehyde product in the prior art is less than 99.5%, and meanwhile, the final purity of the product in all the examples of the invention is not less than 99.60% as is clear from the table 1, which fully demonstrates the effectiveness of the purification process.
Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered by the scope of the claims of the present invention.