Method for synthesizing citric acid ester type compound

Abstract

The invention discloses a method for synthesizing a citric acid ester type compound, which belongs to the technical field of chemical synthesis. The method comprises the following steps of: using citric acid and fatty alcohol as main raw materials, and using benzene sulfonic acid or amino benzene sulfonic acid as a catalyst; and performing esterification and the purification processes of acetylation, neutralization, washing, drying, distillation and the like. The catalyst has rich sources, a low cost and high activity, can be separated from an esterification liquid easily after the neutralization, is coke-free during the distillation, has less corrosion to equipment, and is safe and environment-friendly; the water generated by the esterification is separated out by adopting a binary heterogeneous separation technique, and no water separating agent is additionally added; and acetyl citric acid ester is produced by adopting an esterification-acetylation continuous synthesis method, the flow is greatly simplified, and a synthesis process is shortened. The citric acid ester prepared by the method has the advantages of high quality, high purity, low degree of color and wide applicationrange.

Description

technical field

[0001] The invention belongs to the technical field of chemical synthesis, and relates to a synthesis process of citrate compounds, in particular to a method for synthesizing citrate compounds with citric acid as the main raw material and benzenesulfonic acid or aminobenzenesulfonic acid as the catalyst. Background technique

[0002] 1. Use of citric acid ester

[0003] Citrate compounds are non-toxic, safe and environment-friendly plasticizers that are preferred at home and abroad to replace phthalates. It has the advantages of good compatibility with plastics, high plasticizing efficiency, non-toxic, and low volatility. The plasticized material has good low-temperature flexural performance, is heat-stable when melt-sealed, does not change color, and has excellent cold resistance, light resistance, water resistance, and mildew resistance. It is mainly used for food and vegetable packaging, plastic wrap production, plastic toy processing, pharmaceutical pac...

Examples

Embodiment 1

[0040] Embodiment 1: triethyl citrate is synthesized

[0041] Add 0.2mol (42.0g) of citric acid monohydrate, 0.3g of benzenesulfonic acid, 90ml of 95% (V / V) ethanol and 80ml of water-carrying agent benzene in a three-neck flask with a stirrer and a water separator. Heat to 63-90°C to boil, reflux for 21-49 hours, benzene-ethanol-water forms a ternary minimum azeotrope to distill, cool to normal temperature and the distillate is divided into organic phase and water phase, the organic phase is refluxed, and the water phase is separated out. After the esterification reaction, excess benzene and ethanol were distilled off under reduced pressure. Cool to below 60°C, add 2ml saturated Na 2 CO 3The solution was stirred and neutralized to pH > 8, then transferred to a separatory funnel and allowed to stand for 30 minutes, the brine and the organic phase were separated, and the brine was released, and the organic phase was washed with tap water until neutral. Move the crude product...

Embodiment 2

[0044] Embodiment 2 acetyl triethyl citrate synthesis

[0045] Add 0.2 mol (42.0 g) of citric acid monohydrate, 0.3 g of benzenesulfonic acid, 90 ml of 95% (V / V) ethanol and 80 ml of benzene (water-carrying agent) successively in a three-neck flask equipped with a stirrer and a water separator. Heat to 63-90°C to boil, reflux for 21-49 hours, benzene-ethanol-water forms a ternary minimum azeotrope to distill, cool to normal temperature and the distillate is divided into organic phase and water phase, the organic phase is refluxed, and the water phase is separated out. After the esterification reaction, excess benzene and ethanol were distilled off under reduced pressure. Then add 0.23mol of acetic anhydride, and carry out acetylation reaction at 70°C-90°C for 60-90min; after the acylation reaction is completed, distill off the generated acetic acid and unreacted anhydride under reduced pressure with a jet pump. Cool to below 60°C, add 2ml saturated Na 2 CO 3 The solution w...

Embodiment 3

[0047] Embodiment 3 tributyl citrate is synthesized

[0048] Add 0.2mol (42.0g) of citric acid monohydrate, 0.3g of benzenesulfonic acid and 74g of n-butanol in sequence in a three-necked flask with a stirrer and a water separator, and heat it to a liquid phase of 100-140°C with an oil bath while stirring , reflux reaction for 2.5 hours, n-butanol-water forms a binary minimum azeotrope and distills out. When cooled to normal temperature, the distillate is divided into organic phase and water phase, the organic phase is refluxed, and the water phase is separated. According to the volume of the separated water layer Determine the end point of the reaction. After the esterification reaction was finished, excess butanol was distilled off under reduced pressure. Cool to below 60°C, add 2ml saturated Na 2 CO 3 The solution was stirred and neutralized to pH > 8, then transferred to a separatory funnel and allowed to stand for 30 minutes, the brine and the organic phase were separa...

technical field

[0001] The invention belongs to the technical field of chemical synthesis, and relates to a synthesis process of citrate compounds, in particular to a method for synthesizing citrate compounds with citric acid as the main raw material and benzenesulfonic acid or aminobenzenesulfonic acid as the catalyst. Background technique

[0002] 1. Use of citric acid ester

[0003] Citrate compounds are non-toxic, safe and environment-friendly plasticizers that are preferred at home and abroad to replace phthalates. It has the advantages of good compatibility with plastics, high plasticizing efficiency, non-toxic, and low volatility. The plasticized material has good low-temperature flexural performance, is heat-stable when melt-sealed, does not change color, and has excellent cold resistance, light resistance, water resistance, and mildew resistance. It is mainly used for food and vegetable packaging, plastic wrap production, plastic toy processing, pharmaceutical pac...

Examples

Embodiment 1

[0040] Embodiment 1: triethyl citrate is synthesized

[0041] Add 0.2mol (42.0g) of citric acid monohydrate, 0.3g of benzenesulfonic acid, 90ml of 95% (V / V) ethanol and 80ml of water-carrying agent benzene in a three-neck flask with a stirrer and a water separator. Heat to 63-90°C to boil, reflux for 21-49 hours, benzene-ethanol-water forms a ternary minimum azeotrope to distill, cool to normal temperature and the distillate is divided into organic phase and water phase, the organic phase is refluxed, and the water phase is separated out. After the esterification reaction, excess benzene and ethanol were distilled off under reduced pressure. Cool to below 60°C, add 2ml saturated Na 2 CO 3The solution was stirred and neutralized to pH > 8, then transferred to a separatory funnel and allowed to stand for 30 minutes, the brine and the organic phase were separated, and the brine was released, and the organic phase was washed with tap water until neutral. Move the crude product...

Embodiment 2

[0044] Embodiment 2 acetyl triethyl citrate synthesis

[0045] Add 0.2 mol (42.0 g) of citric acid monohydrate, 0.3 g of benzenesulfonic acid, 90 ml of 95% (V / V) ethanol and 80 ml of benzene (water-carrying agent) successively in a three-neck flask equipped with a stirrer and a water separator. Heat to 63-90°C to boil, reflux for 21-49 hours, benzene-ethanol-water forms a ternary minimum azeotrope to distill, cool to normal temperature and the distillate is divided into organic phase and water phase, the organic phase is refluxed, and the water phase is separated out. After the esterification reaction, excess benzene and ethanol were distilled off under reduced pressure. Then add 0.23mol of acetic anhydride, and carry out acetylation reaction at 70°C-90°C for 60-90min; after the acylation reaction is completed, distill off the generated acetic acid and unreacted anhydride under reduced pressure with a jet pump. Cool to below 60°C, add 2ml saturated Na 2 CO 3 The solution w...

Embodiment 3

[0047] Embodiment 3 tributyl citrate is synthesized

[0048] Add 0.2mol (42.0g) of citric acid monohydrate, 0.3g of benzenesulfonic acid and 74g of n-butanol in sequence in a three-necked flask with a stirrer and a water separator, and heat it to a liquid phase of 100-140°C with an oil bath while stirring , reflux reaction for 2.5 hours, n-butanol-water forms a binary minimum azeotrope and distills out. When cooled to normal temperature, the distillate is divided into organic phase and water phase, the organic phase is refluxed, and the water phase is separated. According to the volume of the separated water layer Determine the end point of the reaction. After the esterification reaction was finished, excess butanol was distilled off under reduced pressure. Cool to below 60°C, add 2ml saturated Na 2 CO 3 The solution was stirred and neutralized to pH > 8, then transferred to a separatory funnel and allowed to stand for 30 minutes, the brine and the organic phase were separa...