CN-121991332-A - Synthesis method of polycaprolactone

Abstract

The invention discloses a method for synthesizing polycaprolactone, and belongs to the technical field of polyester synthesis. The method utilizes the tin dichloride dihydrate and the triol to generate metal alcohol compounds with high catalytic and initiating activities in the caprolactone to quickly initiate the ring-opening polymerization of the epsilon-caprolactone to obtain high-component polycaprolactone, and compared with the existing polycaprolactone synthesis method, the adopted metal alcohol compounds have high initiating activities and low cost, can quickly improve the conversion rate of the epsilon-caprolactone, and the generated polycaprolactone has high molecular weight and narrow distribution, and is favorable for large-scale use.

Inventors

• LI CHANGCUN
• ZHENG HAIXIA

Assignees

• 中国石油化工股份有限公司
• 中石化湖南石油化工有限公司

Dates

Publication Date

20260508

Application Date

20241107

Claims (7)

1. 1. A method for synthesizing polycaprolactone is characterized in that epsilon-caprolactone, tin dichloride dihydrate and triol are heated for ring-opening polymerization reaction, and then the polycaprolactone and the tin dichloride dihydrate are obtained; the triol has the following structure: ; Wherein n is an integer of 1 to 7.
2. 2. The method for synthesizing polycaprolactone according to claim 1, wherein tin dichloride dihydrate and triol react in epsilon-caprolactone to generate metal alcohol compound with catalytic and initiating activity, and the metal alcohol compound has a structure of formula 1: ; Wherein, the N is an integer of 1 to 7.
3. 3. The method for synthesizing polycaprolactone according to claim 1, wherein n is an integer of 1 to 3.
4. 4. The method for synthesizing polycaprolactone according to claim 3, wherein the metal alcohol compound has a structure of formula 2:
5. 5. the method for synthesizing polycaprolactone according to claim 1, wherein the molar ratio of the tin dichloride dihydrate to the triol is 0.46:1-1.04:1.
6. 6. The method for synthesizing polycaprolactone according to claim 1, wherein the method comprises the following steps: The mol ratio of the epsilon-caprolactone to the tin dichloride dihydrate is 3034:1-5958:1; the molar ratio of epsilon-caprolactone to triol is 2746:1-3130:1.
7. 7. The method for synthesizing polycaprolactone according to claim 1, 2, 4, 5 or 6, wherein the ring-opening polymerization reaction is carried out under the protection of nitrogen at 130-180 ℃ for 30-120 min.

Description

Synthesis method of polycaprolactone Technical Field The invention relates to a method for synthesizing polycaprolactone, in particular to a method for synthesizing polycaprolactone by using metal alcohol compounds to initiate and catalyze ring-opening polymerization of polycaprolactone, belonging to the technical field of polyester synthesis. Background Thermoplastic Polycaprolactone (PCL) has the advantages of good biodegradability, biocompatibility, shape memory property and the like, and can be used as a medical orthopedic splint, a medical locating membrane, an absorbable surgical suture, a medical bone nail, an in-vivo implantation stent and the like. At present, caprolactone ring-opening polymerization catalysts reported in domestic and foreign documents mainly comprise titanium-based, aluminum-based, rare earth metal compound systems, active hydrogen, enzyme catalytic systems and the like, but the prior art reports that ① has the defects of low catalytic activity, large required catalyst amount, low epsilon-caprolactone conversion speed and low conversion rate. ② Catalysts are expensive (e.g., rare earth metal catalysts). ③ The polymerization time required is long. ④ The reaction conditions are harsh, and are mostly carried out in a vacuum drying oven. ⑤ Generally, a solution polymerization process is adopted, the steps are complicated, and the solvent needs to be recycled. Chinese patent (publication No. CN 101628971A) discloses a method for synthesizing polycaprolactone, which is completed by one-step reaction, namely, alkynyl poly (amide-amine) of 1 generation to 3 generation initiates the body ring-opening polymerization of caprolactone to prepare the end alkynyl linear or sector structure polycaprolactone. The polymerization temperature is 130 ℃, the reaction time is 24 hours, and the highest yield of polycaprolactone is 92.2%. The method requires longer reaction time and lower yield. Chinese patent (publication No. CN 105968036A) discloses a metal complex for the efficient controllable ring opening of epsilon-caprolactone, in particular to thiourea metal salt, which is suitable for the bulk polymerization and melt polymerization process of epsilon-caprolactone and is also suitable for the slow controllable polymerization in solution, but the cost of raw materials required for synthesizing the thiourea metal salt is higher. Chinese patent (publication No. CN 109336916A) discloses the synthesis of a beta-pyridine enamine bidentate aluminum complex and the catalysis of epsilon-caprolactone ring-opening polymerization. And (3) carrying out condensation reaction on the 2- (2-pyridyl) -acetophenone and aromatic amine containing different substituents to obtain a ligand containing two nitrogen atoms, and then coordinating with alkyl aluminum to synthesize the metal complex of beta-pyridine enamine bidentate aluminum. The method can be used for catalyzing ring-opening polymerization of epsilon-caprolactone, the polymerization temperature is 70-80 ℃, the reaction time is 20-240 min, and the method has more working procedures. Mary F. Mahon et al (Inorganic Chemistry, 2006) 45 (2282-2287.) report the synthesis of the novel compound titanium aryloxide, the X-ray structure and its use in epsilon-caprolactone ring-opening polymerization, a series of titanium catechol was prepared, and characterized by single crystal X-ray diffraction studies, the electron effect and the space effect of the ligand were studied, and the novel compound titanium aryloxide was used in epsilon-caprolactone ring-opening polymerization to give polycaprolactone with a maximum yield of 79% at room temperature, and the yield of polycaprolactone obtained by this method was low. Chinese patent (publication No. CN 114605630A) discloses a rapid synthesis method of thermoplastic polycaprolactone, wherein the adopted catalyst needs to be synthesized independently, and the catalyst is a liquid catalyst which is easy to oxidize, can influence the color of the subsequent polycaprolactone product, and has low conversion rate of the catalytic epsilon-caprolactone. Disclosure of Invention Aiming at the defects of ring-opening polymerization of polycaprolactone in the prior art, the invention aims to provide a method for synthesizing polycaprolactone, which can quickly improve the conversion rate of epsilon-caprolactone by using tin dichloride dihydrate and triol to generate a metal alcohol compound with high catalytic and initiating activity as a catalytic and initiating system, and has the characteristics of less ① auxiliary agent consumption and low cost compared with the prior method for synthesizing polycaprolactone; the ② epsilon-caprolactone has high conversion rate and high final conversion rate, the ③ epsilon-caprolactone ring-opening polymerization has short reaction time required for preparing the polycaprolactone, the ④ reaction condition is mild, the catalyst is bulk polymerization, the ⑤ catalyst has good stability, and the synthesi