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Product separation process for preparing lactic acid by means of oxidation of 1,2-propanediol

A technology for lactic acid and products, which is applied in the field of product separation technology for oxidizing 1,2-propylene glycol to lactic acid, can solve problems such as low efficiency and complicated process, and achieves reduction of separation energy consumption, cost saving, and increase of separation energy consumption and separation cost. Effect

Active Publication Date: 2018-03-30
南京大学扬州化学化工研究院
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In 2015, the world's lactic acid production was about 200,000 to 250,000 tons, about 70% of which were produced by fermentation. Through the screening and improvement of microbial strains, lactic acid can be produced by fermentation with agricultural and sideline products as raw materials, and then added Calcium hydroxide is neutralized, filtered, and recrystallized to obtain pure calcium lactate, and sulfuric acid is acidified to obtain chemically pure lactic acid; but this method is more complicated and inefficient
However, there are no reports and patents on the separation of 1,2-propanediol selective catalytic oxidation products and the separation of formic acid, acetic acid and lactic acid

Method used

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  • Product separation process for preparing lactic acid by means of oxidation of 1,2-propanediol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Single separation: 1,2-PDO oxidation product, containing (NaOH aqueous solution 60.0 mol %; unreacted 1,2-PDO 4.8 mol %; LA 25.0 mol %; HCOOH 1.2 mol %; HAc 6.2 mol %; CO 3 2- 2.8mol%). Add H first 2 SO 4 Acidify to pH = 2.0 to neutralize NaOH and CO 3 2- , vacuum rotary evaporation evaporates H 2 O (reuse as ester extraction agent); add CH 3 OH extraction (m(CH 3 OH): m (acid) = 0.5: 1.0 (g / g)), filtered, and the solid Na 2 SO 4 extracted; the alcohol filtrate was directly added to the reactor for esterification (70 °C, 12 h), during the esterification process methyl acetate, methyl formate and unreacted CH 3 OH can be distilled out directly, add pipetting agent H 2 O under vacuum and reduced pressure (0.5 kPa, 60 ℃) to remove methyl lactate (m(H 2 O):m(lactate)=2.0:1.0(g / g)), the remaining lactic acid continues to be esterified (70 ℃, 12 h), after esterification, add pipetting agent H 2 O(m(H 2 O):m(lactate)=2.0:1.0 (g / g)) removed; the residue was distil...

Embodiment 2

[0028] Single separation: 1,2-PDO oxidation product, containing (NaOH aqueous solution 80.0 mol %; unreacted 1,2-PDO 1.0 mol %; LA 13.0 mol %; HCOOH 1.0 mol %; HAc 3.0 mol %; CO 3 2- 2.0 mol%). H first 2 SO 4 Acidify to pH=2.0, neutralize NaOH and CO 3 2- , and the H 2 O (reuse as ester extraction agent); add C 2 h 5 OH extraction (m(C 2 h 5OH): m (acid) = 1.0 : 1.0 (g / g)), filter, the solid Na 2 SO 4 Extraction; the alcohol filtrate is directly added to the reactor for esterification (90°C, 10 h), during the esterification process ethyl acetate, ethyl formate and unreacted C 2 h 5 OH can be distilled out directly, add pipetting agent H 2 O under vacuum and reduced pressure (1.0 kPa, 65 ℃) to remove ethyl lactate (m(H 2 O):m(lactate)=5.0:1.0 (g / g)), the remaining lactic acid continues to be esterified (90 ℃, 10 h), after esterification, add pipetting agent H 2 O(m(H 2 O): m (lactate) = 5.0:1.0 (g / g)) removed; after removing ethyl lactate, the residue was disti...

Embodiment 3

[0030] Cyclic separation: 1,2-PDO oxidation product, containing (NaOH aqueous solution 61.0 mol %; unreacted 1,2-PDO10.0 mol%; LA15.5 mol%; HCOOH 5.0 mol%; HAc 3.5 mol%; CO 3 2- 5.0 mol%). H first 2 SO 4 Acidify to pH = 4.0 to neutralize NaOH and CO 3 2- , and the H 2 O (reuse as ester extraction agent); add CH 3 OH extraction (m(CH 3 OH): m (acid) = 3.0 : 1.0 (g / g)), filter, the solid Na 2 SO 4 extracted; the filtrate was directly added to the continuous reactor for esterification (70 °C, 12 h), methyl acetate, methyl formate and unreacted CH 3 OH can be distilled out directly, add pipetting agent H 2 O under vacuum and reduced pressure (10 kPa, 75 ℃) to remove methyl lactate (m(H 2 O): m (lactate) = 1.0 : 1.0 (g / g)), the remaining lactic acid continues to be esterified (70 ℃, 12 h), after esterification, add pipetting agent H 2 O(m(H 2 O): m (lactate) = 1.0 : 1.0 (g / g)) removed; the residue was distilled under reduced pressure (1.0 kPa, 100 ℃), and the unreacte...

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Abstract

The invention provides a product separation process for preparing lactic acid by means of selective catalytic oxidation of 1,2-propanediol (1,2-PDO). A separation object is a 1,2-PDO oxidized lactic acid product mixture solution which contains a NaOH aqueous solution, unreacted 1,2-PDO, lactic acid, formic acid, acetic acid and carbonate. The separation process includes the following steps of acidification, extraction, esterification, distillation under reduced pressure and hydrolysis. According to the separation process, 1,2-PDO oxidation mixtures are completely separated to obtain high-purity lactic acid and lactic anhydride, the yield is high, by adopting a ester extracting agent, the separation energy consumption and the equipment input cost are reduced, separated and added substancescan be recycled and reutilized, and the separation process completely causes no waste water discharge, saves the cost and is efficient and environmentally friendly.

Description

technical field [0001] The invention relates to a product separation process for producing lactic acid by oxidation of 1,2-propanediol (1,2-PDO), and mainly relates to a separation process for formic acid, acetic acid, 1,2-propanediol and lactic acid. Background technique [0002] Lactic acid is a multipurpose fine chemical, and its derivatives such as lactic acid and its salts have been widely used in food, pharmaceutical, chemical, leather, textile, environmental protection and agriculture. The polylactic acid produced by polycondensation reaction of lactic acid is a green and environmentally friendly new bio-based degradable material, which has broad application prospects in emerging fields such as textiles, plastics, packaging, agricultural mulch, modern medicine, and 3D printing. Due to the wide application range and huge market potential of lactic acid products, especially the superior function of polylactic acid in biodegradable materials, it has aroused great researc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/42C07C51/493C07C51/47C07C51/487C07C59/08
CPCC07C51/42C07C51/47C07C51/487C07C51/493C07C59/08
Inventor 赵兵范以宁张忠良陆海孟惠恩娟周静卫松雪
Owner 南京大学扬州化学化工研究院
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