CN107417533B - Dimethyl isophthalate and process for producing the same - Google Patents
Dimethyl isophthalate and process for producing the same Download PDFInfo
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- CN107417533B CN107417533B CN201710757339.XA CN201710757339A CN107417533B CN 107417533 B CN107417533 B CN 107417533B CN 201710757339 A CN201710757339 A CN 201710757339A CN 107417533 B CN107417533 B CN 107417533B
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- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
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Abstract
The invention provides dimethyl isophthalate and a production method thereof, wherein the production method comprises the steps of reaction, dealcoholization, alkali washing and rectification; in the reaction, a reactant and a catalyst are taken, the reaction temperature is 100-; the reactants are isophthalic acid and methanol, and the mass ratio of the isophthalic acid to the methanol to the catalyst is 1: 3-4: 0.001-0.003; the method has the advantages of low reaction temperature and short esterification time in the whole production process, reduces energy consumption and saves energy; the dimethyl isophthalate produced by the production method has the purity of more than or equal to 99.7 percent, the water content of less than or equal to 1000ppm and the acid value of less than or equal to 0.1 KOH/g.
Description
Technical Field
The invention relates to dimethyl isophthalate and a production method thereof, belonging to the field of fine chemical engineering.
Background
The existing production method is that isophthalic acid and methanol react under the catalysis of sulfuric acid by using toluene or cyclohexane as a water-carrying agent. The method increases the procedure of separating the water-carrying agent, and a part of materials are brought out along with the water-carrying agent, so that the consumption is increased, in addition, the quality of the product is influenced by the existence of the water-carrying agent, and the purity of the product produced by the method can only reach 99.5 percent at most.
The prior art has the following defects in the production of dimethyl isophthalate:
(1) the reaction process is longer;
(2) the requirement on equipment is high, and the production cost is high;
(3) the product yield is low and the quality is poor.
Disclosure of Invention
The invention provides a dimethyl isophthalate and a production method thereof for solving the technical problems, wherein isophthalic acid and methanol are taken as raw materials, concentrated sulfuric acid is taken as a catalyst, and the raw materials and the concentrated sulfuric acid are mixed according to the mass ratio of 1: 3.0-4.0: 0.001-0.003, and then are put into a reaction kettle for full and uniform stirring; then, heating, synthesizing, dealcoholizing, alkali washing and rectifying to obtain the dimethyl isophthalate product.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for producing dimethyl isophthalate is characterized by comprising the following steps: reaction, dealcoholization, alkali washing and rectification.
As the preferable technical scheme of the invention, the reaction comprises taking a reactant and a catalyst, wherein the reaction temperature is 100-130 ℃, and the pressure is 0.2-0.6 MPa; the reactants are isophthalic acid and methanol, and the mass ratio of the isophthalic acid to the methanol to the catalyst is 1: 3-4: 0.001-0.003.
As a preferable technical scheme of the invention, the dealcoholization temperature is 100-130 ℃.
As a preferable technical scheme of the invention, the rectification comprises the steps of pumping the layered alkali washing ester into a rectification kettle for rectification treatment, wherein the vacuum of the rectification kettle is less than 2mmhg, and collecting 180 ℃ fraction with a distillation range of 130-.
As a preferable technical scheme of the invention, the dealcoholization temperature is 110 ℃.
As a preferable technical scheme of the invention, the reaction has the reaction temperature of 125-129.5 ℃, the pressure of 0.55-0.6MPa and the reaction time of 3 hours.
As a preferable technical scheme of the invention, the reaction temperature is 118-120 ℃, the pressure is 0.36-0.4MPa, and the mass ratio of the isophthalic acid, the methanol and the concentrated sulfuric acid is 1: 3.5: 0.002.
the allyl diglycol carbonate is characterized in that the purity of the allyl diglycol carbonate is more than or equal to 99.7 percent, the moisture content is less than or equal to 1000ppm, and the acid value is less than or equal to 0.1 KOH/g.
As a preferable technical scheme of the invention, the purity of the allyl diglycol carbonate is 99.9 percent, the moisture content is 200-300ppm, and the acid value is less than or equal to 0.1 KOH/g.
By adopting the technical scheme, the invention has the beneficial effects that:
compared with the production method of dimethyl isophthalate in the prior art, the method has the following beneficial effects:
(1) the method has the advantages of low reaction temperature and short esterification time in the whole production process, reduces energy consumption and saves energy;
(2) according to the method, the reaction is carried out under normal pressure, the requirement on the pressure resistance of equipment is low, and the production cost is low;
(3) the method of the invention has the advantages that the total reaction yield can reach more than 97 percent;
(4) compared with the product in the prior art, the product obtained by the invention has greatly improved quality, the purity is more than or equal to 99.7 percent, the water content is less than or equal to 1000ppm, and the acid value is less than or equal to 0.1 KOH/g.
Drawings
FIG. 1: the process flow diagram of the invention.
Detailed Description
The following description of the preferred embodiments of the present invention is provided for the purpose of illustration and description, and is in no way intended to limit the invention.
The invention is described in detail below: the invention relates to a method for producing dimethyl isophthalate, which comprises the steps of mixing isophthalic acid and methanol serving as raw materials and concentrated sulfuric acid serving as a catalyst according to the mass ratio of 1: 3.0-4.0: 0.001-0.003, putting into a reaction kettle, and fully and uniformly stirring; then, heating, synthesizing, dealcoholizing, alkali washing and rectifying to obtain the dimethyl isophthalate product.
The chemical reaction equation related to the invention is as follows:
the molecular formula is as follows: c8H6O4+2CH3OH→C10H10O4+2H2O。
EXAMPLE 1 dimethyl isophthalate and Process for producing the same
The method comprises the following steps:
1) reaction: weighing isophthalic acid, methanol and a catalyst to react in a reaction kettle;
the reaction is carried out by heating with steam at the temperature of 100 ℃ and 130 ℃, the pressure of 0.2-0.6MPa and the reaction time of 3 hours;
the mass ratio of the isophthalic acid to the methanol to the concentrated sulfuric acid is 1: 3-4: 0.001-0.003;
the catalyst is concentrated sulfuric acid.
2) Dealcoholizing: slowly opening an alcohol evaporation valve, gradually reducing the pressure and the temperature in the reaction kettle, and carrying out dealcoholization treatment on the product obtained in the step 1) at the temperature of 100-;
and condensing the methanol by a condenser, and recovering for later use.
3) Alkali washing: putting the crude product obtained in the step 2) into a neutralization kettle, adding a 5-8% sodium carbonate aqueous solution, and neutralizing residual acidic reactants and catalyst concentrated sulfuric acid to obtain alkaline washing ester;
and settling the alkali washing ester to obtain the layered alkali washing ester.
4) And (3) rectification: decompressing and pumping the layered alkali washing ester obtained in the step 3) into a rectifying still for rectifying treatment; heating the distillation kettle, collecting the 130 ℃ fraction with the distillation range of 100 as the front fraction when the vacuum of the distillation kettle is less than 2mmhg, and putting the front fraction into the reaction kettle in the step 1) for recycling;
collecting the fraction with the distillation range of 130-;
the equipment used for heating the distillation kettle is a heat-conducting oil furnace.
And (4) analyzing results: the total reaction yield can reach more than 97 percent, the product quality is high, the purity is more than or equal to 99.7 percent, the water content is less than or equal to 1000ppm, and the acid value is less than or equal to 0.1 KOH/g.
EXAMPLE 2 production of dimethyl isophthalate
The method comprises the following steps:
1) reaction: weighing isophthalic acid, methanol and a catalyst to react in a reaction kettle;
the reaction is carried out by heating with steam at 100-102 deg.C under 0.2-0.25MPa for 3 hr;
the mass ratio of the isophthalic acid to the methanol to the concentrated sulfuric acid is 1: 3: 0.001;
the catalyst is concentrated sulfuric acid.
2) Dealcoholizing: slowly opening an alcohol evaporation valve, gradually reducing the pressure and the temperature in the reaction kettle, and carrying out dealcoholization treatment on the product obtained in the step 1) at the temperature of 100-;
and condensing the methanol by a condenser, and recovering for later use.
3) Alkali washing: putting the crude product obtained in the step 2) into a neutralization kettle, adding a 5-8% sodium carbonate aqueous solution, and neutralizing residual acidic reactants and catalyst concentrated sulfuric acid to obtain alkaline washing ester;
and settling the alkali washing ester to obtain the layered alkali washing ester.
4) And (3) rectification: decompressing and pumping the layered alkali washing ester obtained in the step 3) into a rectifying still for rectifying treatment; heating the distillation kettle, collecting the 130 ℃ fraction with the distillation range of 105-;
collecting the fraction with the distillation range of 130-;
the equipment used for heating the distillation kettle is a heat-conducting oil furnace.
And (4) analyzing results: the total reaction yield can reach 97.9 percent, the product quality is high, the purity is 99.8 percent, the water content is 700-750ppm, and the acid value is less than or equal to 0.1 KOH/g.
EXAMPLE 3 dimethyl isophthalate and production method thereof
The method comprises the following steps:
1) reaction: weighing isophthalic acid, methanol and a catalyst to react in a reaction kettle;
the reaction is carried out by heating with steam at the temperature of 125-;
the mass ratio of the isophthalic acid to the methanol to the concentrated sulfuric acid is 1: 4: 0.003;
the catalyst is concentrated sulfuric acid.
2) Dealcoholizing: slowly opening an alcohol evaporation valve, gradually reducing the pressure and the temperature in the reaction kettle, and carrying out dealcoholization treatment on the product obtained in the step 1) at the temperature of 125-129.5 ℃ and the pressure of normal pressure to obtain an esterified material and methanol;
and condensing the methanol by a condenser, and recovering for later use.
3) Alkali washing: putting the crude product obtained in the step 2) into a neutralization kettle, adding a 5-8% sodium carbonate aqueous solution, and neutralizing residual acidic reactants and catalyst concentrated sulfuric acid to obtain alkaline washing ester;
and settling the alkali washing ester to obtain the layered alkali washing ester.
4) And (3) rectification: decompressing and pumping the layered alkali washing ester obtained in the step 3) into a rectifying still for rectifying treatment; heating the distillation kettle, collecting the 130 ℃ fraction with the distillation range of 100 as the front fraction when the vacuum of the distillation kettle is less than 2mmhg, and putting the front fraction into the reaction kettle in the step 1) for recycling;
collecting the fraction with the distillation range of 130-;
the equipment used for heating the distillation kettle is a heat-conducting oil furnace.
And (4) analyzing results: the total reaction yield can reach 97.8 percent, the product quality is high, the purity is 99.8 percent, the water content is 800ppm, and the acid value is less than or equal to 0.1 KOH/g.
EXAMPLE 4 dimethyl isophthalate and production method thereof
The method comprises the following steps:
1) reaction: weighing isophthalic acid, methanol and a catalyst to react in a reaction kettle;
the reaction is carried out by heating with steam at the temperature of 118-120 ℃, the pressure of 0.36-0.4MPa and the reaction time of 3 hours;
the mass ratio of the isophthalic acid to the methanol to the concentrated sulfuric acid is 1: 3.5: 0.002;
the catalyst is concentrated sulfuric acid.
2) Dealcoholizing: slowly opening an alcohol evaporation valve, gradually reducing the pressure and the temperature in the reaction kettle, and carrying out dealcoholization treatment on the product obtained in the step 1) at the temperature of 110 ℃ and the pressure of normal pressure to obtain an esterified material and methanol;
and condensing the methanol by a condenser, and recovering for later use.
3) Alkali washing: putting the crude product obtained in the step 2) into a neutralization kettle, adding a 5-8% sodium carbonate aqueous solution, and neutralizing residual acidic reactants and catalyst concentrated sulfuric acid to obtain alkaline washing ester;
and settling the alkali washing ester to obtain the layered alkali washing ester.
4) And (3) rectification: decompressing and pumping the layered alkali washing ester obtained in the step 3) into a rectifying still for rectifying treatment; heating the distillation kettle, collecting the 130 ℃ fraction with the distillation range of 100 as the front fraction when the vacuum of the distillation kettle is less than 2mmhg, and putting the front fraction into the reaction kettle in the step 1) for recycling;
collecting the fraction with the distillation range of 130-;
the equipment used for heating the distillation kettle is a heat-conducting oil furnace.
And (4) analyzing results: the total reaction yield can reach more than 98.3 percent, the product quality is high, the purity is 99.9 percent, the water content is 200-300ppm, and the acid value is less than or equal to 0.1 KOH/g.
It should be noted that, isophthalic acid, which is one of the raw materials of the present invention, can also be replaced by corresponding isophthalic anhydride, which can achieve the same effect as the present invention, and is not described herein again.
The method of the invention is also suitable for the production of dimethyl phthalate, can achieve the same effect as the invention, and is not repeated.
Unless otherwise stated, the percentages used in the present invention are percentages by weight, and the proportions described in the present invention are proportions by mass.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (1)
1. A method for producing dimethyl isophthalate is characterized by comprising the following steps: reaction, dealcoholization, alkali washing and rectification;
the reaction: weighing isophthalic acid, methanol and a catalyst to react in a reaction kettle; heating with steam at 118-120 deg.C under 0.36-0.4MPa for 3 hr;
the mass ratio of the isophthalic acid to the methanol to the concentrated sulfuric acid is 1: 3.5: 0.002;
the catalyst is concentrated sulfuric acid;
② dealcoholizing: slowly opening an alcohol evaporation valve, gradually reducing the pressure and the temperature in the reaction kettle, and dealcoholizing the product obtained in the step I at the temperature of 110 ℃ and the pressure of normal pressure to obtain an esterified material and methanol;
condensing the methanol by a condenser, and recovering for later use;
③ washing with alkali: putting the crude product obtained in the step two into a neutralization kettle, adding a 5-8% sodium carbonate aqueous solution, and neutralizing residual acidic reactants and catalyst concentrated sulfuric acid to obtain alkaline washing ester;
carrying out sedimentation treatment on the alkali washing ester to obtain layered alkali washing ester;
fourthly, rectification: decompressing and pumping the layered alkali washing ester obtained in the step (III) into a rectifying still for rectifying treatment; heating the rectifying kettle, collecting 130 ℃ fraction with the distillation range of 100 as front fraction when the vacuum of the rectifying kettle is less than 2mmhg, and putting the front fraction into the reaction kettle in the step I for cyclic utilization;
collecting the fraction with the distillation range of 130-;
the equipment used by the heating rectifying still is a heat-conducting oil furnace;
the dimethyl isophthalate prepared by the method has the total reaction yield of over 98.3 percent, high product quality, purity of 99.9 percent, water content of 200 and 300ppm and acid value of less than or equal to 0.1 KOH/g.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2004003044A2 (en) * | 2002-06-28 | 2004-01-08 | Jean-Marie Lehn | Dynamers: polymeric materials exhibiting reversible formation and component exchange |
| CN101402473A (en) * | 2008-11-06 | 2009-04-08 | 河南庆安化工高科技股份有限公司 | Method for reutilization of wastewater in elasticizer production |
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| CN102241591A (en) * | 2011-04-30 | 2011-11-16 | 白银阳明银光化工有限公司 | Method for producing high-purity diethyl m-phthalate |
| CN102976946A (en) * | 2012-12-13 | 2013-03-20 | 烟台泰和新材料股份有限公司 | Method for synthesizing dimethyl isophthalate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2004003044A2 (en) * | 2002-06-28 | 2004-01-08 | Jean-Marie Lehn | Dynamers: polymeric materials exhibiting reversible formation and component exchange |
| CN101402473A (en) * | 2008-11-06 | 2009-04-08 | 河南庆安化工高科技股份有限公司 | Method for reutilization of wastewater in elasticizer production |
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