	US 11,987,567 B2
	Synthesis method of lactide by confinement effect catalysis of crystalline porous polymer material
Yingjie Zhao, Shandong (CN); Wenqi Qiu, Shandong (CN); Hui Liu, Shandong (CN); Zhenxiu Zhang, Shandong (CN); and Jinyu Zhao, Shandong (CN)
Assigned to QINGDAO UNIVERSITY OF SCIENCE AND TECHNOLOGY, Shandong (CN)
Filed by Qingdao University of Science and Technology, Shandong (CN)
Filed on Aug. 31, 2022, as Appl. No. 17/899,814.
Claims priority of application No. 202111078761.5 (CN), filed on Sep. 15, 2021.
Prior Publication US 2023/0094928 A1, Mar. 30, 2023
Int. Cl. C07D 319/12 (2006.01); B01J 31/04 (2006.01); B01J 37/00 (2006.01); B01J 37/02 (2006.01); B01J 37/03 (2006.01); B01J 37/04 (2006.01); B01J 37/06 (2006.01)

CPC C07D 319/12 (2013.01) [B01J 31/04 (2013.01); B01J 37/009 (2013.01); B01J 37/0236 (2013.01); B01J 37/031 (2013.01); B01J 37/04 (2013.01); B01J 37/06 (2013.01); B01J 2231/005 (2013.01); B01J 2531/002 (2013.01)]

2 Claims

1. A synthesis method of lactide by confinement effect catalysis of crystalline porous polymer material, comprising following steps:

step (I) synthesis of catalysts comprising:

a) placing a compound A, a compound B, mesitylene and 1,4-dioxane into a reaction vessel;

b) mixing the contents of the reaction vessel evenly;

c) adding acetic acid to the reaction vessel;

d) de-aerating the contents of the reaction vessel;

e) vacuum sealing the reaction vessel;

f) placing the reaction vessel in an oven for heating;

g) filtering precipitates from the reaction vessel;

h) washing the precipitates with a Soxhlet extractor;

i) vacuum drying the precipitates; and

j) obtaining solid catalysts;

wherein a structural formula of the compound A is:

wherein R₁═OH, CH₃, OCH₃, C₂H₅, F, Cl, Br or I;

wherein compound B is:

step (II) synthesis of lactide by confinement effect catalysis comprising:

a) adding the catalysts obtained in step (I), solvents, and lactic acid to a reaction vessel for reaction;

b) cooling down the reaction vessel slowly after the reaction;

c) filtering the contents of the reaction vessel after the reaction;

d) washing the contents of the reaction vessel after the reaction;

e) removing the solvents from the contents of the reaction vessel after the reaction at low pressure; and

f) obtaining crude lactide;

step (III) lactide purification comprising:

a) conducting liquid-liquid extraction on the crude lactide obtained in step (II) with methylbenzene and water,

b) combining organic phases of the liquid-liquid extraction,

c) removing the solvents of the combined organic phases at low pressure, and

d) obtaining lactide,

wherein in step (I) a mole ratio between the compound A and the compound B is 4:7; a volume ratio among the mesitylene, the 1,4-dioxane, and the acetic acid is 15:5:1; and a mole ratio between the compound A and the mesitylene is 1:25;

wherein in step (I) the method for de-aerating comprises freeze-pump-thaw cycling;

wherein in step (I) the conditions for heating in the oven comprise 80° C. for 3 days;

wherein in step (I) the conditions for washing with the Soxhlet extractor comprise specifically: washing four hours with THF and acetone; and conditions for vacuum drying comprise: 80° C. for 12 hours;

wherein lactic acid in step (II) comprises L-lactic acid of 90 percent purity;

wherein the solvents in step (II) comprise methylbenzene or ortho-xylene; wherein a mass ratio between the catalysts and the lactic acid is 1:10, and a weight/volume ratio of the catalysts and the solvents is 1:1 g/cm³;

wherein reaction conditions in step (II) comprise: reaction time of 5 hr and reaction temperature 120° C.;

wherein in step (II) washing is done by washing with acetonitrile.