Branched polymerization type Schiff base metal compound as well as preparation method and application thereof

Abstract

The invention provides a branched polymerization type Schiff base metal compound which has a structure as shown in a formula I to a formula IV. The branched multi-center polymerization type Schiff base metal compound provided by the invention is simple in synthesis method, easy to separate and purify, relatively high in product purity, relatively high in catalytic activity when being used as a glycolide and lactide polymerization reaction catalyst, capable of increasing the polymerization reaction speed and high in product conversion rate; experimental results show that the reaction yield can reach 96.9% when the catalyst is used for preparing the poly (lactic-co-glycolic acid).

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a branched polymerized Schiff base metal compound and a preparation method and application thereof. Background Art

[0002] Poly(lactide-co-glycolide) (PLGA) is a degradable functional polymer with good biocompatibility, non-toxicity and good film-forming properties. PLGA is composed of two structural units, lactic acid and glycolic acid, and has the advantages of both polyester materials. It is widely used in the biomedical field, such as surgical sutures, orthopedic fixation and tissue repair materials. Compared with polylactic acid (PLA), PLGA can control the polymer degradation time by adjusting the content of glycolic acid, and different monomer ratios can be used to prepare different types of PLGA. Generally speaking, the degree of PLGA degradation increases with the increase of the glycolic acid ratio.

[0003] At present, the preparation of PLGA mostly adopts the ring-opening polymerization method. Common ring-opening polymerization is to prepare glycolic acid and lactic acid into two monomers, glycolide (GA) and lactide (LA), respectively, and then obtain PLGA random copolymers by ring-opening polymerization of GA and LA. Another ring-opening polymerization route is to prepare glycolic acid and lactide into two monomers, and then obtain alternating copolymers of PLGA by ring-opening polymerization. The polymer has a regular structure, fixed composition, and relatively stable degradation performance. In the above-mentioned ring-opening polymerization process, stannous octoate is mostly used as a catalyst. In order to further improve the production efficiency, it is generally achieved by increasing the amount of stannous octoate catalyst. However, in the ring-opening polymerization process, if an excessive amount of catalyst is added to the reaction system, the residual metal compound in the product will reduce its thermal stability. Therefore, it is necessary to provide a catalyst with higher catalytic activity to improve the production efficiency of PLGA without excessive use.

[0004] In recent years, Schiff base catalysts have been widely used due to their high catalytic activity, but there are few reports on using them as catalysts for preparing PLGA. In addition, current Schiff base compounds usually need to be purified and then reacted with metal compounds to obtain Schiff base catalysts. The above post-treatment is relatively cumbersome, and a large amount of organic solvents are usually required for purification, which not only increases economic costs, but also pollutes the external environment. In addition, the yield of the Schiff base catalyst finally obtained is only about 80% at most. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a branched polymeric Schiff base metal compound and a preparation method and application thereof, wherein the branched polymeric Schiff base metal compound has high catalytic activity.

[0006] To achieve the above object, the present invention provides a branched polymeric Schiff alkali metal compound having any structure of Formula I to Formula IV:

[0007]

[0008]

[0009] Wherein, R1 is selected from substituted or unsubstituted alkyl or cycloalkyl;

[0010] R2 is selected from substituted or unsubstituted alkyl;

[0011] R3 is selected from hydrogen, halogen, nitro, substituted or unsubstituted alkyl or alkoxy;

[0012] R4 is selected from substituted or unsubstituted alkyl, cycloalkyl, aryl or heteroaryl;

[0013] R5 is selected from halogen, substituted or unsubstituted alkoxy or ester;

[0014] M1 is selected from zinc, cobalt, nickel or tin;

[0015] M2 is selected from aluminum, indium, chromium, iron, manganese, cerium or yttrium;

[0016] m, n, and p are the degrees of polymerization.

[0017] The R1 is preferably a substituted or unsubstituted C2-C10 alkyl or C3-C12 cycloalkyl; more preferably a substituted or unsubstituted C2-C6 alkyl or C5-C6 cycloalkyl; further preferably a substituted or unsubstituted C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl. The R1 has two connection positions.

[0018] The substituent of R1 is preferably one or more of halogen, nitro, hydroxyl, amino, cyano, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, and more preferably one or more of fluorine, chlorine, bromine, nitro, hydroxyl, amino, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, methoxy, ethoxy, propoxy, fluoromethyl, difluoromethyl, and trifluoromethyl.

[0019] In some specific embodiments of the present invention, R1 is selected from the group remaining after removing two hydroxyl groups from ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, 1,5-pentanediol, 1,2-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, heptanediol, octanediol, nonanediol, and decanediol.

[0020] The R2 is preferably a substituted or unsubstituted C3-C10 alkyl group; more preferably a substituted or unsubstituted C3 alkyl group, C4 alkyl group, C5 alkyl group, C6 alkyl group, C7 alkyl group, C8 alkyl group, C9 alkyl group or C10 alkyl group; the R2 has three connection positions.

[0021] The substituent of R2 is preferably one or more of halogen, nitro, hydroxyl, amino, cyano, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, and more preferably one or more of fluorine, chlorine, bromine, nitro, hydroxyl, amino, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, methoxy, ethoxy, propoxy, fluoromethyl, difluoromethyl, and trifluoromethyl.

[0022] In some specific embodiments of the present invention, R2 is selected from the group remaining after removing three hydroxyl groups from propylene glycol, 1,1,1-trimethylolpropane, 1,1,1-(trimethylol)-ethane, 1,2,4-butanetriol, 1,2,3-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,3,5-cyclohexanetriol, 1,2,7-heptanetriol, 1,2,3-heptanetriol, 1,2,8-octantriol, 1,2,9-nonanetriol, and 1,2,10-decanetriol.

[0023] The R3 is preferably hydrogen, halogen, nitro, substituted or unsubstituted C1-C6 alkyl or C1-C6 alkoxy; more preferably hydrogen, halogen, nitro, substituted or unsubstituted C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C1 alkoxy, C2 alkoxy, C3 alkoxy, C4 alkoxy, C5 alkoxy, C6 alkoxy; further preferably hydrogen, halogen, nitro, substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, n-propoxy or isopropoxy.

[0024] The substituent of R3 is preferably one or more of halogen, nitro, hydroxyl, amino, cyano, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, and more preferably one or more of fluorine, chlorine, bromine, nitro, hydroxyl, amino, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, methoxy, ethoxy, propoxy, fluoromethyl, difluoromethyl, and trifluoromethyl.

[0025] In some specific embodiments of the present invention, R3 is selected from hydrogen, -CH3, -CH2CH3, -CH(CH3)2, -OCH(CH3)2, -C(CH3)3, -OCH3 or -OCH2CH3.

[0026] The R4 is preferably a substituted or unsubstituted C2-C6 alkyl, C3-C12 cycloalkyl, C6-C12 aryl or C4-C11 heteroaryl; more preferably a substituted or unsubstituted C2-C6 alkyl, C5-C6 cycloalkyl, C6 aryl or C4-C5 heteroaryl. The aryl or heteroaryl is preferably a monocyclic aryl or heteroaryl. The heteroatoms of the heteroaryl include, but are not limited to, one or more of N, O, and S. The R4 is further preferably a substituted or unsubstituted C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or phenyl.

[0027] The substituent of R4 is preferably one or more of halogen, nitro, hydroxyl, amino, cyano, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy. More preferably, it is one or more of fluorine, chlorine, bromine, nitro, hydroxyl, amino, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, methoxy, ethoxy, propoxy, fluoromethyl, difluoromethyl, trifluoromethyl. R4 has two connection positions.

[0028] In some specific embodiments of the present invention, R4 is selected from ethylenediamine, 1,3-propylenediamine, 1,2-propylenediamine, 2-methyl-1,3-propylenediamine, 2,2'-dimethylpropylenediamine, 1,4-butylenediamine, 1,2-cyclohexyldiamine, o-phenylenediamine, 3-nitro o-phenylenediamine, 4-nitro o-phenylenediamine, 3-bromo o-phenylenediamine, 4-bromo o-phenylenediamine, 4,5-dibromo o-phenylenediamine, 4-bromo-5-fluoro o-phenylenediamine, 4-bromo-5-methyl o-phenylenediamine, 4-chloro-5-bromo o-phenylenediamine, 3-methyl-5-bromo o-phenylenediamine, 4 The group remaining after removing two amino groups from 4-methoxy-o-phenylenediamine, 4-chloro-5-fluoro-o-phenylenediamine, 4,5-dichloro-o-phenylenediamine, 4-chloro-o-phenylenediamine, 4-trifluoromethyl-o-phenylenediamine, 3-chloro-o-phenylenediamine, 3-chloro-5-trifluoromethyl-o-phenylenediamine, 4,5-difluoro-o-phenylenediamine, 4-fluoro-o-phenylenediamine, 3-fluoro-o-phenylenediamine, 3,4-difluoro-o-phenylenediamine, 3,5-difluoro-o-phenylenediamine, 4,5-dimethyl-o-phenylenediamine, 4-methyl-o-phenylenediamine, 3,5-dimethyl-o-phenylenediamine, and 4-chloro-5-methyl-o-phenylenediamine.

[0029] The R5 is preferably halogen, substituted or unsubstituted C1-C6 alkoxy or ester; more preferably fluorine, chlorine, bromine, substituted or unsubstituted methoxy, ethoxy, n-propoxy, isopropoxy, methyl ester or ethyl ester.

[0030] The substituent of R4 is preferably one or more of halogen, nitro, hydroxyl, amino, cyano, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, and more preferably one or more of fluorine, chlorine, bromine, nitro, hydroxyl, amino, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, methoxy, ethoxy, propoxy, fluoromethyl, difluoromethyl, and trifluoromethyl.

[0031] In some specific embodiments of the present invention, the R4 is selected from -OCH3, -OCH2CH3, -OCH(CH3)2, -Cl or -OOCCH3.

[0032] The m is the degree of polymerization, which is preferably any integer from 5 to 100.

[0033] The n is the degree of polymerization, and is preferably any integer from 1 to 20.

[0034] The p is the degree of polymerization, which is preferably any integer from 5 to 100.

[0035] The present invention provides a method for preparing the above-mentioned branched polymeric Schiff base metal compound, comprising the following steps:

[0036] a) reacting a chloromethyl salicylaldehyde compound with a diol metal compound and a triol metal compound to obtain a mixture of a di-salicylaldehyde compound and a tri-salicylaldehyde compound;

[0037] b) reacting a mixture of a di-salicylaldehyde compound and a tri-salicylaldehyde compound with a diamino compound to obtain a branched Schiff base polymer;

[0038] c) reacting the branched Schiff base polymer with a metal compound to obtain a multi-center branched polymeric Schiff base metal compound.

[0039] The present invention has no particular limitation on the source of the chloromethyl salicylaldehyde, which can be commercially available or prepared according to methods well known to those skilled in the art. Preferably, the synthesis of the chloromethyl salicylaldehyde comprises the following steps:

[0040] The salicylaldehyde compound is reacted with the formaldehyde compound under the action of a catalyst to generate chloromethyl salicylaldehyde.

[0041] The salicylaldehyde compound preferably includes at least one of salicylaldehyde, 3-methyl salicylaldehyde, 3-methoxy salicylaldehyde, 3-ethoxy salicylaldehyde, 3-tert-butyl salicylaldehyde, 3-bromo salicylaldehyde, 3-chloro salicylaldehyde, 5-chloro salicylaldehyde, 5-methyl salicylaldehyde, and 5-nitrosalicylicylaldehyde.

[0042] The formaldehyde compound preferably includes at least one of formaldehyde, trioxymethylene or polyoxymethylene.

[0043] The molar ratio of the salicylaldehyde compound to the formaldehyde compound is preferably 1:1 to 1:2.

[0044] The reaction temperature is preferably 0 to 100° C., and the reaction time is preferably 2 to 72 hours.

[0045] The catalyst is preferably at least one of HCl, concentrated sulfuric acid, phosphoric acid, acetic acid, aluminum chloride, zinc chloride, and tin chloride.

[0046] The present invention has no particular limitation on the sources of the above-mentioned diol metal compound and triol metal compound, which can be commercially available or prepared by methods well known to those skilled in the art. Preferably, the synthesis of the diol metal compound comprises the following steps:

[0047] The glycol is reacted with an alkali metal to obtain a glycol alkali metal compound.

[0048] The reaction temperature is preferably 25 to 100° C., and the reaction time is preferably 1 to 10 h.

[0049] The molar ratio of the diol to the alkali metal is preferably 1:2.5 to 1:4.

[0050] The alkali metal preferably includes one or more of lithium, sodium and potassium.

[0051] The diol preferably includes at least one of ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, heptanediol, octanediol (preferably 1,2-octanediol), nonanediol, and decanediol (preferably 1,2-decanediol).

[0052] Preferably, the synthesis of the triol metal compound comprises the following steps:

[0053] The triol is reacted with an alkali metal to obtain a triol alkali metal compound.

[0054] The reaction temperature is preferably 25 to 100° C., and the reaction time is preferably 1 to 10 h.

[0055] The molar ratio of the triol to the alkali metal is preferably 1:3.5 to 1:6.

[0056] The alkali metal preferably includes one or more of lithium, sodium and potassium.

[0057] The triol preferably includes at least one of propylene glycol, 1,1,1-trimethylolpropane, 1,1,1-(trimethylol)-ethane, 1,2,4-butanetriol, 1,2,3-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,3,5-cyclohexanetriol, 1,2,7-heptanetriol, 1,2,3-heptanetriol, 1,2,8-octantriol, 1,2,9-nonanetriol, and 1,2,10-decantriol.

[0058] Preferably, in the step a), the ratio of the molar amount of the chloromethyl salicylaldehyde compound to the total molar amount of the diol metal compound and the triol metal compound is 2:1 to 4:1.

[0059] The molar ratio of the diol metal compound to the triol metal compound is preferably 100:0.5-20.

[0060] The reaction temperature is preferably 20 to 110° C., and the reaction time is preferably 2 to 48 hours.

[0061] In some specific embodiments of the present invention, the reaction equation of the chloromethyl salicylaldehyde compound and the diol metal compound is as follows:

[0062]

[0063] Wherein, M is selected from lithium, sodium or potassium.

[0064] In some specific embodiments of the present invention, the reaction equation of the chloromethyl salicylaldehyde compound and the triol metal compound is as follows:

[0065]

[0066] Wherein, M is selected from lithium, sodium or potassium.

[0067] In the present invention, in the process of obtaining the di-salicylaldehyde compound and the tri-salicylaldehyde compound by reacting chloromethyl salicylaldehyde with a diol metal compound and a triol metal compound, a one-pot method can be adopted, and the products do not need to be separated, thereby simplifying the process flow.

[0068] In the step b), the ratio of the total molar amount of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound to the molar amount of the diamino compound is preferably 1:0.6-1.5.

[0069] The molar ratio of the di-salicylaldehyde compound to the tri-salicylaldehyde compound is preferably 100:0.5-20.

[0070] The reaction temperature is preferably 20 to 100° C., and the reaction time is preferably 1 to 48 hours.

[0071] The diamino compounds preferably include ethylenediamine, 1,3-propylenediamine, 1,2-propylenediamine, 2-methyl-1,3-propylenediamine, 2,2'-dimethylpropylenediamine, 1,4-butylenediamine, 1,2-cyclohexyldiamine, o-phenylenediamine, 3-nitro o-phenylenediamine, 4-nitro o-phenylenediamine, 3-bromo o-phenylenediamine, 4-bromo o-phenylenediamine, 4,5-dibromo o-phenylenediamine, 4-bromo-5-fluoro o-phenylenediamine, 4-bromo-5-methyl o-phenylenediamine, 4-chloro-5-bromo o-phenylenediamine, 3-methyl-5-bromo o-phenylenediamine, 4 -methoxy o-phenylenediamine, 4-chloro-5-fluoro o-phenylenediamine, 4,5-dichloro o-phenylenediamine, 4-chloro o-phenylenediamine, 4-trifluoromethyl o-phenylenediamine, 3-chloro o-phenylenediamine, 3-chloro-5-trifluoromethyl o-phenylenediamine, 4,5-difluoro o-phenylenediamine, 4-fluoro o-phenylenediamine, 3-fluoro o-phenylenediamine, 3,4-difluoro o-phenylenediamine, 3,5-difluoro o-phenylenediamine, 4,5-dimethyl o-phenylenediamine, 4-methyl-o-phenylenediamine, 3,5-dimethyl o-phenylenediamine, 4-chloro-5-methyl o-phenylenediamine.

[0072] In some specific embodiments of the present invention, the reaction equation of step b) is as follows:

[0073]

[0074] In the step c), the metal compound preferably includes at least one of zinc chloride, zinc acetate, ethyl zinc, stannous chloride, ferric chloride, indium chloride, cobalt acetate, aluminum isopropoxide, aluminum ethoxide, nickel acetate and triethylaluminum.

[0075] The molar ratio of the diamino compound residue to the metal compound in the branched Schiff base polymer is preferably 1:1 to 1:1.2.

[0076] The reaction temperature is preferably 20 to 120° C., and the reaction time is preferably 2 to 100 h.

[0077] The present invention provides the use of the branched polymeric Schiff base metal compound or the branched polymeric Schiff base metal compound prepared by the preparation method as a catalyst in the preparation of poly(lactide-glycolide).

[0078] Based on this, the present invention provides a method for preparing poly(lactide-glycol) comprising the following steps:

[0079] In an inert atmosphere, glycolide and lactide, or glycolide, lactide and an epoxy compound are reacted in the presence of a catalyst and an initiator to obtain poly(glycol-lactide);

[0080] The catalyst is the branched polymeric Schiff alkali metal compound or the branched polymeric Schiff alkali metal compound prepared by the above preparation method.

[0081] The ratio of the mass of the catalyst to the total mass of the glycolide and the lactide is preferably 1:(20-2000).

[0082] The initiator is preferably an alcohol compound.

[0083] The alcohol compound preferably includes at least one of isopropanol, butanol, pentanol, hexanol, benzyl alcohol, cyclohexanol, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, heptanediol, octanediol, 1,2-octanediol, nonanediol, decanediol, 1,2-decanediol, undecanol, and dodecanol.

[0084] The ratio of the molar amount of the initiator to the total molar amount of the glycolide and the lactide is preferably 1:(100-2000).

[0085] The ratio of the molar amount of the epoxy compound to the total molar amount of the glycolide and the lactide is preferably (0-10):(90-100).

[0086] The epoxy compound is preferably any one or more of propylene oxide, butylene oxide, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-epoxyoctane, 1,2-epoxydodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, allyl glycidyl ether, styrene oxide, isopropyl glycidyl ether, tert-butyl glycidyl ether, octyl glycidyl, phenyl glycidyl ether, 2-toluene glycidyl ether or benzyl glycidyl ether.

[0087] In the above reaction, the epoxy compound may be added or not, and whether it is added depends on the metal element in the catalyst. When the metal element is aluminum, tin or indium, the amount of epoxy compound added is 0; when the metal element is zinc, iron, cobalt, nickel, manganese, chromium, cerium or yttrium, the amount of epoxy compound added is not 0.

[0088] The molar ratio of the glycolide to the lactide is preferably (1-99):(99-1).

[0089] The reaction temperature is preferably 120-240° C., and the reaction time is preferably 2-24 hours.

[0090] The preparation method has mild reaction conditions, high product yield and reduced production cost of the catalyst.

[0091] Compared with the prior art, the present invention provides a branched polymeric Schiff base metal compound having structures shown in Formula I to Formula IV. The branched multi-center polymeric Schiff base metal compound provided by the present invention has a simple synthesis method, is easy to separate and purify, has a high product purity, is used as a catalyst for the polymerization reaction of glycolide and lactide, has a high catalytic activity, improves the polymerization reaction speed, and has a high product conversion rate; experimental results show that the reaction yield of poly(glycolide) lactide prepared by the catalyst of the present invention can reach 96.9%. DETAILED DESCRIPTION

[0092] In order to further illustrate the present invention, the branched polymeric Schiff alkali metal compound provided by the present invention and its preparation method and application are described in detail below in conjunction with the embodiments. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0093] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0094] Example 1

[0095] 1 mol of ethylene glycol, 2.5 mol of metallic sodium, and 400 mL of anhydrous toluene were added to a 1 L round-bottom flask, mixed and stirred, and heated to 65 ° C. After the metallic sodium no longer decreased, the unreacted metallic sodium was removed, and then the toluene was removed in vacuo to obtain 105.1 g of sodium ethylene glycol. The sodium butanediol, sodium hexanediol, and sodium cyclohexanediol used in the embodiments of the present invention were prepared according to the method, and ethylene glycol was replaced by butanediol, hexanediol, and cyclohexanediol, respectively.

[0096] Example 2

[0097] 0.1 mol of propylene glycol, 0.4 mol of sodium metal, and 100 mL of anhydrous toluene were added to a 500 mL round-bottom flask, mixed and stirred, and heated to 70 ° C. After the sodium metal no longer decreased, the unreacted sodium metal was removed, and then the toluene was removed in vacuo to obtain 15.6 g of sodium propylene glycol. The 1,2,4-butanetriol sodium, 1,2,6-hexanetriol sodium, and trimethylol sodium propane used in the embodiments of the present invention were prepared according to the method, and propylene glycol was replaced by 1,2,4-butanetriol, 1,2,6-hexanetriol, and 1,1,1-trimethylolpropane, respectively.

[0098] Example 3

[0099] 3.1 Add 122g of salicylaldehyde, 85.1g of formaldehyde solution (37wt%) and 800mL of concentrated hydrochloric acid (37wt%) into a 2L round-bottom flask, mix and stir, and continuously introduce HCl gas dried with concentrated sulfuric acid. The reaction temperature is 15°C, and the HCl gas is introduced for 10h. The round-bottom flask is sealed and allowed to stand for 35h, then the temperature is raised to 60°C and stirred for reaction. After 36h, the crude product is filtered, dissolved with ether and washed with saturated sodium bicarbonate solution until neutral, then washed three times with saturated NaCl solution, 40g of anhydrous magnesium sulfate is added and dried for 24h. After filtering, the solvent is removed under normal pressure, and the resulting solid is recrystallized with petroleum ether and dried in vacuo at 30°C for 24h to obtain 153.6g of 5-chloromethyl salicylaldehyde with a yield of 90.1%.

[0100] 3.2 53 g of sodium ethylene glycol prepared in Example 1 was dissolved in 200 mL of toluene, and then added dropwise to 800 mL of the toluene solution of 5-chloromethyl salicylaldehyde (173.1 g) at a rate of 2 mL / min. After the addition was complete, the temperature was raised to 60°C and the reaction was continued for 15 h. Then 0.79 g of sodium propylene glycol prepared in Example 2 was added and the reaction was continued for 10 h. The heating was stopped and 100 mL of water was added. After mixing evenly, the material was transferred to a separatory funnel and allowed to stand to separate the water layer. The oil phase was washed with deionized water several times until the water phase was neutral. 30 g of anhydrous sodium sulfate was added and dried for 24 h. After filtering, the solvent was removed in vacuo to obtain 159.8 g of a disalicylicylaldehyde compound and a trisalicylicylaldehyde compound.

[0101] The obtained products were analyzed by MALDI-TOF-MS, and the m / z values ​​(332, 497) on the spectrum corresponded to the molecular weights of disalicylicylaldehyde and trisalicylicylaldehyde compounds, proving the successful synthesis of disalicylicylaldehyde and trisalicylicylaldehyde compounds.

[0102] The obtained disalicylicylaldehyde and trisalicylicylaldehyde compounds were analyzed by nuclear magnetic resonance, and the hydrogen spectrum results were obtained as follows: δ=10.10-10.28ppm corresponds to the characteristic chemical shift of hydrogen on the aldehyde group in the disalicylicylaldehyde and trisalicylicylaldehyde compounds, δ=6.82-7.65ppm corresponds to the characteristic chemical shift of hydrogen on the benzene ring in the disalicylicylaldehyde and trisalicylicylaldehyde compounds, δ=4.73-4.87ppm corresponds to the characteristic chemical shift of hydrogen on the methylene group connected to the benzene ring in salicylaldehyde, δ=3.65-3.75ppm corresponds to the characteristic chemical shift of hydrogen on the methine group in the trisalicylicylaldehyde compounds, and δ=3.42-3.56ppm corresponds to the characteristic chemical shift of hydrogen on the methylene group connected to oxygen in ethylene glycol and propylene glycol in the compounds.

[0103] This further proves the successful synthesis of di-salicylaldehyde compounds and tri-salicylaldehyde compounds.

[0104] Example 4

[0105] 4.1 Add 136 g of 5-methyl salicylaldehyde, 121.6 g of formaldehyde solution (37 wt %) and 600 mL of concentrated hydrochloric acid (37 wt %) into a 2 L round-bottom flask, mix and stir, and continuously introduce HCl gas dried with concentrated sulfuric acid. The reaction temperature is 10 ° C. The HCl gas is introduced for 12 h. Then the round-bottom flask is sealed, stirred at 25 ° C. for 30 h, and then the temperature is raised to 50 ° C. and stirred for reaction. After 24 h, the crude product is filtered, dissolved with ether and washed with saturated sodium bicarbonate solution until neutral, and then washed three times with saturated NaCl solution, 60 g of anhydrous magnesium sulfate is added and dried for 24 h. After filtering, the solvent is removed under normal pressure, and then the obtained solid is recrystallized from petroleum ether and dried in vacuo at 30 ° C. for 24 h to obtain 167 g of 3-chloromethyl-5-methyl salicylaldehyde with a yield of 90.5%.

[0106] 4.2 67 g of sodium butanediol prepared in Example 1 was dissolved in 500 mL of toluene, and then added dropwise at a rate of 3 mL / min to 900 mL of the toluene solution of 3-chloromethyl-5-methyl salicylaldehyde (188.9 g) above. After the addition was complete, the temperature was raised to 55°C and the reaction was continued for 20 h. Then 1.6 g of sodium trimethoxide propane prepared in Example 2 was added and the reaction was continued for 12 h. 150 mL of water was added and the mixture was mixed evenly and then transferred to a separatory funnel. The mixture was allowed to stand to separate the water layer. The oil phase was washed with deionized water several times until the water phase was neutral. 50 g of anhydrous sodium sulfate was added and dried for 24 h. After filtering, the solvent was removed in vacuo to obtain 175.3 g of di-salicylaldehyde compound and tri-salicylaldehyde compound.

[0107] The obtained products were analyzed by MALDI-TOF-MS, and the m / z values ​​(388, 581) on the spectrum corresponded to the molecular weights of disalicylicylaldehyde and trisalicylicylaldehyde compounds, proving the successful synthesis of disalicylicylaldehyde and trisalicylicylaldehyde compounds.

[0108] Example 5

[0109] 5.1 Add 152g 3-methoxysalicylaldehyde, 89g formaldehyde solution (37wt%) and 500mL concentrated hydrochloric acid (37wt%) into a 2L round-bottom flask, mix and stir, and continuously introduce HCl gas dried with concentrated sulfuric acid. The reaction temperature is 20°C, and the HCl gas is introduced for 15h. Then the round-bottom flask is sealed, stirred at 30°C for 24h, and then the temperature is raised to 55°C for stirring reaction. After 20h, the crude product is filtered, dissolved with ether and washed with saturated sodium bicarbonate solution until neutral, then washed three times with saturated NaCl solution, added with 80g anhydrous magnesium sulfate and dried for 24h. After filtering, the solvent is removed under normal pressure, and then the obtained solid is recrystallized with petroleum ether and dried in vacuo at 30°C for 24h to obtain 182.6g of 5-chloromethyl-3-methoxysalicylaldehyde with a yield of 91.1%.

[0110] 5.2 81 g of sodium hexanediol prepared in Example 1 was dissolved in 400 mL of toluene, and then added dropwise at a rate of 5 mL / min to 1000 mL of the toluene solution of the above-mentioned 5-chloromethyl-3-methoxysalicylaldehyde (208.8 g). After the addition was complete, the temperature was raised to 65°C and the reaction was continued for 12 h. Then 2.08 g of sodium 1,2,4-butanetriol prepared in Example 2 was added and the reaction was continued for 8 h. 200 mL of water was added and the mixture was transferred to a separatory funnel after mixing evenly. The mixture was allowed to stand to separate the water layer. The oil phase was washed with deionized water several times until the water phase was neutral. 60 g of anhydrous sodium sulfate was added and dried for 24 h. After filtering, the solvent was removed in vacuo to obtain 220.2 g of a disalicylicylaldehyde compound and a trisalicylicylaldehyde compound.

[0111] The obtained products were analyzed by MALDI-TOF-MS, and the m / z values ​​(448, 601) on the spectrum corresponded to the molecular weights of disalicylicylaldehyde and trisalicylicylaldehyde compounds, proving the successful synthesis of disalicylicylaldehyde and trisalicylicylaldehyde compounds.

[0112] Example 6

[0113] 6.1 Add 178 g of 3-tert-butyl salicylaldehyde, 97.3 g of formaldehyde solution (37 wt %) and 400 mL of concentrated hydrochloric acid (37 wt %) into a 2 L round-bottom flask, mix and stir, and continuously introduce HCl gas dried with concentrated sulfuric acid. The reaction temperature is 25 ° C. The HCl gas is introduced for 8 h. Then the round-bottom flask is sealed and stirred at 25 ° C for 35 h. Then the temperature is raised to 60 ° C and stirred for reaction. After 30 h, the crude product is filtered, dissolved with ether and washed with saturated sodium bicarbonate solution until neutral, then washed three times with saturated NaCl solution, 50 g of anhydrous magnesium sulfate is added and dried for 24 h. After filtering, the solvent is removed under normal pressure, and the resulting solid is recrystallized from petroleum ether and dried in vacuo at 30 ° C for 24 h to obtain 208.1 g of 5-chloromethyl-3-tert-butyl salicylaldehyde with a yield of 91.5%.

[0114] 6.2 80 g of sodium cyclohexanediol prepared in Example 1 was dissolved in 600 mL of toluene, and then added dropwise at a rate of 5 mL / min to 1200 mL of the above-mentioned toluene solution of 5-chloromethyl-3-tert-butyl salicylaldehyde (239.1 g). After the addition was complete, the temperature was raised to 70°C and the reaction was continued for 10 h. Then 3.4 g of sodium 1,2,6-hexanetriol prepared in Example 2 was added and the reaction was continued for 6 h. 250 mL of water was added and the mixture was transferred to a separatory funnel after mixing evenly. The mixture was allowed to stand to separate the water layer. The oil phase was washed with deionized water several times until the water phase was neutral. 100 g of anhydrous sodium sulfate was added and dried for 24 h. After filtering, the solvent was removed in vacuo to obtain 241.5 g of a disalicylicylaldehyde compound and a trisalicylicylaldehyde compound.

[0115] The obtained products were analyzed by MALDI-TOF-MS, and the m / z values ​​(498, 707) on the spectrum corresponded to the molecular weights of disalicylicylaldehyde and trisalicylicylaldehyde compounds, proving the successful synthesis of disalicylicylaldehyde and trisalicylicylaldehyde compounds.

[0116] Example 7

[0117] 7.1 37.1 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 3 was dissolved in 200 mL of toluene, mixed with 6 g of ethylenediamine, stirred and heated to 60°C. After 15 h, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 100 mL of ethanol was added for washing, filtered and dried to obtain 40.1 g of branched polymeric Schiff base with a yield of 93%.

[0118] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 7000 g / mol.

[0119] 7.2 Dissolve 8.6 g of the above-mentioned branched polymeric Schiff base in 50 mL of toluene, mix with 50 mL of toluene solution of 4.08 g of aluminum isopropoxide, heat to 80°C, and after 72 hours, remove the toluene by vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 50 mL of ethanol for washing, filter, and dry to obtain 9.7 g of multi-center branched polymeric Schiff base aluminum catalyst with a yield of 94.0%.

[0120] 7.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 21.6 g of lactide, 0.558 g of dodecanol and 0.5 g of the above-mentioned multi-center branched polymerization type Schiff base aluminum catalyst were added to the reaction bottle in sequence, mixed and stirred, and quickly heated to 180°C. After 7 hours, 358.1 g of poly(glycol-lactide) was obtained with a yield of 96.9%.

[0121] The obtained poly(lactide-glycol) was subjected to gel permeation chromatography analysis, and the number average molecular weight of the poly(lactide-glycol) was measured to be 105000 g / mol.

[0122] Example 8

[0123] 8.1 37.7 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 3 was dissolved in 200 mL of toluene, mixed with 11.4 g of 1,2-cyclohexanediamine, stirred and heated to 65° C. After 12 h, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 150 mL of ethanol was added for washing, filtered and dried to obtain 45.9 g of branched polymeric Schiff base with a yield of 93.5%.

[0124] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 6600 g / mol.

[0125] 8.2 Dissolve 9.82 g of the above-mentioned branched polymeric Schiff base in 100 mL of tetrahydrofuran, mix with 3.54 g of cobalt acetate in 50 mL of tetrahydrofuran solution, heat to 65°C, and after 24 hours, remove the tetrahydrofuran by vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 50 mL of ethanol for washing, filter, and dry to obtain 10.2 g of a multi-center branched polymeric Schiff base cobalt catalyst.

[0126] 8.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 43.2 g of lactide, 1.16 g of isopropyl glycidyl ether, 0.651 g of dodecanol and 2.4 g of the above-mentioned multi-center branched polymeric Schiff base cobalt catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was rapidly raised to 185°C. After 6 hours, 372.8 g of poly(glycol-lactide) was obtained with a yield of 95.3%.

[0127] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 83000 g / mol.

[0128] Example 9

[0129] 9.1 38.7 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 3 was dissolved in 200 mL of toluene, mixed with 15.3 g of 4-nitro-o-phenylenediamine, stirred and heated to 70°C. After 8 h, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 200 mL of ethanol was added for washing, filtered and dried to obtain 50.76 g of branched polymeric Schiff base with a yield of 94%.

[0130] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 5800 g / mol.

[0131] 9.2 Dissolve 10.8 g of the above-mentioned branched polymeric Schiff base in 100 mL of toluene, mix with 20 mL of toluene solution of 2.28 g of triethylaluminum, heat to 75°C, add 20 mL of ethanol after 15 hours, and after 4 hours, remove toluene and ethanol by vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 100 mL of ethanol for washing, filter, and dry to obtain 11.6 g of multi-center branched polymeric Schiff base aluminum catalyst.

[0132] 9.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 64.8 g of lactide, 0.744 g of dodecanol and 2.1 g of the above-mentioned multi-center branched polymer-type Schiff base aluminum catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was quickly raised to 190°C. After 5 hours, 398.4 g of poly(glycol-lactide) was obtained with a yield of 96.5%.

[0133] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 92000 g / mol.

[0134] Example 10

[0135] 10.1 47.6 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 4 was dissolved in 250 ml of toluene, mixed with 7.4 g of 1,3-propylenediamine, and heated to 75°C. After 6 hours, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 200 mL of ethanol was added for washing, filtered, and dried to obtain 51.6 g of branched polymeric Schiff base with a yield of 93.8%.

[0136] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 4600 g / mol.

[0137] 10.2 Dissolve 11 g of the above-mentioned branched polymeric Schiff base in 150 mL of tetrahydrofuran, mix with 50 mL of ethanol solution of 3.66 g of zinc acetate, heat to 60°C, and after 30 hours, remove toluene and ethanol by vacuuming at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 50 mL of ethanol for washing, filter, and dry to obtain 11.3 g of a multi-center branched polymeric Schiff base zinc catalyst.

[0138] 10.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 86.4 g of lactide, 2.6 g of tert-butyl glycidyl ether, 1.8 g of the above-mentioned multi-center branched polymeric Schiff base zinc catalyst and 0.48 g of benzyl alcohol were added into the reaction bottle in sequence, mixed and stirred, and the temperature was rapidly raised to 195°C. After 4 hours, 417.9 g of poly(glycol-lactide) was obtained with a yield of 96.2%.

[0139] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 86000 g / mol.

[0140] Embodiment 11

[0141] 11.1 45.6 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 4 was dissolved in 250 ml of toluene, mixed with 18.7 g of 4-bromo-o-phenylenediamine, and heated to 70°C. After 12 h, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 250 mL of ethanol was added for washing, filtered, and dried to obtain 60.6 g of branched polymeric Schiff base with a yield of 94.3%.

[0142] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 6900 g / mol.

[0143] 11.2 Dissolve 12.86 g of the above-mentioned branched polymeric Schiff base in 150 mL of toluene, mix with 30 mL of toluene solution of 3.24 g of ethoxyaluminum, heat to 85°C, and after 36 hours, remove the toluene by vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 100 mL of ethanol for washing, filter, and dry to obtain 13.5 g of a multi-center branched polymeric Schiff base aluminum catalyst.

[0144] 11.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 108 g of lactide, 0.558 g of dodecanol and 2.7 g of the above-mentioned multi-center branched polymer-type Schiff base aluminum catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was quickly raised to 175°C. After 10 hours, 440.9 g of poly(glycol-lactide) was obtained with a yield of 96.7%.

[0145] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 95000 g / mol.

[0146] Example 12

[0147] 12.1 44.1 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 4 was dissolved in 300 ml of toluene, mixed with 8.8 g of 2-methyl-1,3-propylenediamine, stirred and heated to 65°C. After 15 hours, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 200 mL of ethanol was added for washing, filtered and dried to obtain 49.62 g of branched polymeric Schiff base with a yield of 93.8%.

[0148] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 7100 g / mol.

[0149] 12.2 Dissolve 10.58 g of the above-mentioned branched polymeric Schiff base in 200 mL of tetrahydrofuran, mix with 60 mL of ethanol solution of 4.42 g of indium chloride, heat to 55°C, and after 24 hours, remove toluene and ethanol by vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 100 mL of ethanol for washing, filter, and dry to obtain 12.4 g of multi-center branched polymeric Schiff base indium catalyst.

[0150] 12.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 129.6 g of lactide, 0.93 g of dodecanol and 3 g of the above-mentioned multi-center branched polymeric Schiff base indium catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was rapidly raised to 170°C. After 12 hours, 454.2 g of poly(glycol-lactide) was obtained with a yield of 95.1%.

[0151] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 72000 g / mol.

[0152] Embodiment 13

[0153] 13.1 49.8 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 5 was dissolved in 300 ml of toluene, mixed with 10.8 g of o-phenylenediamine, stirred and heated to 60°C. After 20 hours, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 250 mL of ethanol was added for washing, filtered and dried to obtain 56.53 g of branched polymeric Schiff base with a yield of 93.3%.

[0154] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 10500 g / mol.

[0155] 13.2 Dissolve 12.12 g of the above-mentioned branched polymeric Schiff base in 150 mL of tetrahydrofuran, mix with 3.46 g of manganese acetate in 60 mL of ethanol solution, heat to 60°C, and after 24 hours, remove the tetrahydrofuran and ethanol by vacuuming at a vacuum degree of 500 Pa. When no more liquid is distilled out, add 50 mL of ethanol for washing, filter, and dry to obtain 12.1 g of a multi-center branched polymeric Schiff base manganese catalyst.

[0156] 13.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 151.2 g of lactide, 3 g of phenyl glycidyl ether, 3.3 g of the above-mentioned multi-center branched polymeric Schiff base manganese catalyst and 0.54 g of benzyl alcohol were added into the reaction bottle in sequence, mixed and stirred, and the temperature was rapidly raised to 165°C. After 15 hours, 476.7 g of poly(glycol-lactide) was obtained with a yield of 95.5%.

[0157] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 80000 g / mol.

[0158] Embodiment 14

[0159] 14.1 49.3 g of the mixture of the di-salicylaldehyde compound and the tri-salicylaldehyde compound prepared in Example 5 was dissolved in 300 ml of tetrahydrofuran, mixed with 7.4 g of 1,2-propylenediamine, stirred and heated to 55°C. After 18 hours, the tetrahydrofuran was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 300 mL of ethanol was added for washing, filtered and dried to obtain 52.44 g of branched polymeric Schiff base with a yield of 92.5%.

[0160] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 10900 g / mol.

[0161] 14.2 Dissolve 11.34 g of the above-mentioned branched polymeric Schiff base in 200 mL of toluene, mix with 50 mL of toluene solution of 4.08 g of aluminum isopropoxide, heat to 80°C, and after 48 hours, remove the toluene by vacuum at a vacuum degree of 500 Pa. When no more liquid is distilled out, add 50 mL of ethanol for washing, filter, and dry to obtain 12.2 g of a multi-center branched polymeric Schiff base aluminum catalyst.

[0162] 14.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 172.8 g of lactide, 0.93 g of dodecanol and 3.6 g of the above-mentioned multi-center branched polymer-type Schiff base aluminum catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was quickly raised to 160°C. After 18 hours, 500.0 g of poly(glycol-lactide) was obtained with a yield of 96%.

[0163] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 90000 g / mol.

[0164] Embodiment 15

[0165] 15.1 48.8 g of the mixture of the di-salicylaldehyde compound and the tri-salicylaldehyde compound prepared in Example 5 was dissolved in 300 ml of tetrahydrofuran, mixed with 14.2 g of 3-chloro-o-phenylenediamine, stirred and heated to 50°C. After 24 hours, the tetrahydrofuran was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 250 mL of ethanol was added for washing, filtered and dried to obtain 58.09 g of branched polymeric Schiff base with a yield of 92.2%.

[0166] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 14100 g / mol.

[0167] 15.2 Dissolve 12.6 g of the above-mentioned branched polymeric Schiff base in 200 mL of tetrahydrofuran, mix with 3.52 g of nickel acetate in 60 mL of ethanol solution, heat to 65°C, and after 20 hours, remove the tetrahydrofuran and ethanol by vacuum at a vacuum degree of 300 Pa, add 50 mL of ethanol for washing, filter, and dry. When no more liquid is distilled out, 12.63 g of a multi-center branched polymeric Schiff base nickel catalyst is obtained.

[0168] 15.3 The reaction flask was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 194.4 g of lactide, 1.16 g of isopropyl glycidyl ether, 1.12 g of dodecanol and 3.9 g of the above-mentioned multi-center branched polymer-type Schiff base nickel catalyst were added to the reaction flask in sequence, mixed and stirred, and the temperature was rapidly raised to 165°C. After 10 hours, 518.5 g of poly(glycol-lactide) was obtained with a yield of 95.6%.

[0169] The poly(lactide-glycol) obtained by the present invention was subjected to gel permeation chromatography analysis, and the number average molecular weight of the poly(lactide-glycol) was measured to be 78000 g / mol.

[0170] Example 16

[0171] 16.1 53.9 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 6 was dissolved in 300 ml of tetrahydrofuran, mixed with 12.2 g of 4-methyl-o-phenylenediamine, stirred and heated to 45°C. After 30 h, the tetrahydrofuran was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 300 mL of ethanol was added for washing, filtered and dried to obtain 60.81 g of branched polymeric Schiff base with a yield of 92%.

[0172] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 16100 g / mol.

[0173] 16.2 Dissolve 13.22 g of the above-mentioned branched polymeric Schiff base in 250 mL of toluene, mix with 50 mL of toluene solution of 3.24 g of ethoxyaluminum, heat to 90°C, and after 16 hours, remove the toluene by vacuum at a vacuum degree of 500 Pa. When no more liquid is distilled out, add 80 mL of ethanol for washing, filter, and dry to obtain 13.63 g of a multi-center branched polymeric Schiff base aluminum catalyst.

[0174] 16.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 216 g of lactide, 1.12 g of dodecanol and 4.2 g of the above-mentioned multi-center branched polymer-type Schiff base aluminum catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was quickly raised to 170°C. After 8 hours, 543.1 g of poly(glycol-lactide) was obtained with a yield of 96.3%.

[0175] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 87000 g / mol.

[0176] Embodiment 17

[0177] 17.1 53.4 g of the mixture of the di-salicylaldehyde compound and the tri-salicylaldehyde compound prepared in Example 6 was dissolved in 300 ml of tetrahydrofuran, mixed with 7.4 g of 1,3-propylenediamine, stirred and heated to 50°C. After 36 hours, the tetrahydrofuran was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 350 mL of ethanol was added for washing, filtered and dried to obtain 56.18 g of branched polymeric Schiff base with a yield of 92.4%.

[0178] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 17100 g / mol.

[0179] 17.2 Dissolve 12.16 g of the above-mentioned branched polymeric Schiff base in 250 mL of tetrahydrofuran, mix with 3.24 g of ferric chloride in 60 mL of ethanol solution, heat to 60°C, and after 20 hours, remove the tetrahydrofuran and ethanol under vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 100 mL of ethanol for washing, filter, and dry to obtain 12.9 g of a multi-center branched polymeric Schiff base iron catalyst.

[0180] 17.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 244.8 g of lactide, 1.3 g of tert-butyl glycidyl ether, 1.12 g of dodecanol and 4.2 g of the above-mentioned multi-center branched polymeric Schiff base iron catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was quickly raised to 155°C. After 12 hours, 565.5 g of poly(glycol-lactide) was obtained with a yield of 95.4%.

[0181] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 80000 g / mol.

[0182] Embodiment 18

[0183] 18.1 52.9 g of the mixture of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound prepared in Example 6 was dissolved in 300 ml of toluene, mixed with 17.7 g of 4,5-dichloro-o-phenylenediamine, stirred and heated to 55°C. After 30 hours, the toluene was removed by vacuum at a vacuum degree of 300 Pa. When no more liquid was distilled out, 300 mL of ethanol was added for washing, filtered and dried to obtain 65.59 g of branched polymeric Schiff base with a yield of 92.9%.

[0184] The obtained branched polymeric Schiff base was analyzed by gel permeation chromatography, and the number average molecular weight of the branched polymeric Schiff base was measured to be 23600 g / mol.

[0185] 18.2 Dissolve 14.12 g of the above-mentioned branched polymeric Schiff base in 200 mL of tetrahydrofuran, mix with 40 mL of ethanol solution of 2.72 g of zinc chloride, heat to 65°C, and after 15 hours, remove the tetrahydrofuran and ethanol by vacuum at a vacuum degree of 300 Pa. When no more liquid is distilled out, add 50 mL of ethanol for washing, filter, and dry to obtain 14.19 g of a multi-center branched polymeric Schiff base zinc catalyst.

[0186] 18.3 The reaction bottle was repeatedly evacuated and filled with nitrogen, and 348 g of glycolide, 288 g of lactide, 3 g of phenyl glycidyl ether, 1.12 g of dodecanol and 4.2 g of the above-mentioned multi-center branched polymeric Schiff base zinc catalyst were added to the reaction bottle in sequence, mixed and stirred, and the temperature was quickly raised to 150°C. After 15 hours, 609.3 g of poly(glycol-lactide) was obtained with a yield of 95.8%.

[0187] The obtained poly(lactide-glycol) was analyzed by gel permeation chromatography, and the number average molecular weight of the poly(lactide-glycol) was measured to be 82000 g / mol.

[0188] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A branched polymeric Schiff alkali metal compound having a structure shown in Formula I to Formula IV: in, R1 is selected from substituted or unsubstituted alkyl or cycloalkyl; R2 is selected from substituted or unsubstituted alkyl; R3 is selected from hydrogen, halogen, nitro, substituted or unsubstituted alkyl or alkoxy; R4 is selected from substituted or unsubstituted alkyl, cycloalkyl, aryl or heteroaryl; R5 is selected from halogen, substituted or unsubstituted alkoxy or ester; M1 is selected from zinc, cobalt, nickel or tin; M2 is selected from aluminum, indium, chromium, iron, manganese, cerium or yttrium; m, n, and p are the degrees of polymerization.

2. The branched polymeric Schiff alkali metal compound according to claim 1, characterized in that: The R1 is selected from substituted or unsubstituted C2-C10 alkyl or C3-C12 cycloalkyl; The R2 is selected from substituted or unsubstituted C3-C10 alkyl; The R3 is selected from hydrogen, halogen, nitro, substituted or unsubstituted C1-C6 alkyl or C1-C6 alkoxy; The R4 is selected from substituted or unsubstituted C2-C6 alkyl, C3-C12 cycloalkyl, C6-C12 aryl or C4-C11 heteroaryl; The R5 is selected from halogen, substituted or unsubstituted C1-C6 alkoxy or ester; The m is any integer from 5 to 100; The n is any integer from 1 to 20; The p is any integer from 5 to 100.

3. The branched polymeric Schiff alkali metal compound according to claim 2, characterized in that: The R1 is selected from substituted or unsubstituted C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl; R2 is selected from substituted or unsubstituted C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl or C10 alkyl; The R3 is selected from hydrogen, halogen, nitro, substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, n-propoxy, isopropoxy; R4 is selected from substituted or unsubstituted C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or phenyl; The R5 is selected from halogen, substituted or unsubstituted methoxy, ethoxy, n-propoxy, isopropoxy, carbomethoxy or carboethoxy.

4. The branched polymeric Schiff alkali metal compound according to claim 3, characterized in that: The R1 is selected from the group remaining after removing two hydroxyl groups from ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, 1,5-pentanediol, 1,2-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, heptanediol, octanediol, nonanediol, and decanediol; The R2 is selected from the group remaining after removing three hydroxyl groups from propylene glycol, 1,1,1-trimethylolpropane, 1,1,1-(trimethylol)-ethane, 1,2,4-butanetriol, 1,2,3-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,3,5-cyclohexanetriol, 1,2,7-heptanetriol, 1,2,3-heptanetriol, 1,2,8-octantriol, 1,2,9-nonanetriol, and 1,2,10-decanetriol; R3 is selected from hydrogen, -CH3, -CH2CH3, -CH(CH3)2, -OCH(CH3)2, -C(CH3)3, -OCH3 or -OCH2CH3; The R4 is selected from ethylenediamine, 1,3-propylenediamine, 1,2-propylenediamine, 2-methyl-1,3-propylenediamine, 2,2'-dimethylpropylenediamine, 1,4-butylenediamine, 1,2-cyclohexyldiamine, o-phenylenediamine, 3-nitro o-phenylenediamine, 4-nitro o-phenylenediamine, 3-bromo o-phenylenediamine, 4-bromo o-phenylenediamine, 4,5-dibromo o-phenylenediamine, 4-bromo-5-fluoro o-phenylenediamine, 4-bromo-5-methyl o-phenylenediamine, 4-chloro-5-bromo o-phenylenediamine, 3-methyl-5-bromo o-phenylenediamine, 4-methoxy o-phenylenediamine, The group remaining after removing two amino groups from amine, 4-chloro-5-fluoro-o-phenylenediamine, 4,5-dichloro-o-phenylenediamine, 4-chloro-o-phenylenediamine, 4-trifluoromethyl-o-phenylenediamine, 3-chloro-o-phenylenediamine, 3-chloro-5-trifluoromethyl-o-phenylenediamine, 4,5-difluoro-o-phenylenediamine, 4-fluoro-o-phenylenediamine, 3-fluoro-o-phenylenediamine, 3,4-difluoro-o-phenylenediamine, 3,5-difluoro-o-phenylenediamine, 4,5-dimethyl-o-phenylenediamine, 4-methyl-o-phenylenediamine, 3,5-dimethyl-o-phenylenediamine, and 4-chloro-5-methyl-o-phenylenediamine; The R5 is selected from -OCH3, -OCH2CH3, -OCH(CH3)2, -Cl or -OOCCH3.

5. The method for preparing the branched polymeric Schiff alkali metal compound according to any one of claims 1 to 4, comprising the following steps: a) reacting a chloromethyl salicylaldehyde compound with a diol metal compound and a triol metal compound to obtain a mixture of a di-salicylaldehyde compound and a tri-salicylaldehyde compound; b) reacting a mixture of a di-salicylaldehyde compound and a tri-salicylaldehyde compound with a diamino compound to obtain a branched Schiff base polymer; c) reacting the branched Schiff base polymer with a metal compound to obtain a multi-center branched polymeric Schiff base metal compound.

6. The preparation method according to claim 5, characterized in that: The synthesis of the chloromethyl salicylaldehyde comprises the following steps: The salicylaldehyde compound and the formaldehyde compound are reacted under the action of a catalyst to generate chloromethyl salicylaldehyde; The salicylaldehyde compound includes at least one of salicylaldehyde, 3-methyl salicylaldehyde, 3-methoxy salicylaldehyde, 3-ethoxy salicylaldehyde, 3-tert-butyl salicylaldehyde, 3-bromo salicylaldehyde, 3-chloro salicylaldehyde, 5-chloro salicylaldehyde, 5-methyl salicylaldehyde and 5-nitrosalicylicylaldehyde; The formaldehyde compound includes at least one of formaldehyde, trioxymethylene or polyformaldehyde; The molar ratio of the salicylaldehyde compound to the formaldehyde compound is 1:1 to 1:2; The reaction temperature is 0 to 100° C., and the reaction time is 2 to 72 hours; The catalyst is at least one of HCl, concentrated sulfuric acid, phosphoric acid, acetic acid, aluminum chloride, zinc chloride, and tin chloride.

7. The preparation method according to claim 5, characterized in that: The synthesis of the diol metal compound comprises the following steps: reacting a diol with an alkali metal to obtain a diol alkali metal compound; The reaction temperature is 25 to 100° C., and the reaction time is 1 to 10 hours. The molar ratio of the diol to the alkali metal is 1:2.5 to 1:

4. The alkali metal includes one or more of lithium, sodium, and potassium. The synthesis of the triol metal compound comprises the following steps: reacting a triol with an alkali metal to obtain a triol alkali metal compound; The reaction temperature is 25 to 100° C., and the reaction time is 1 to 10 hours. The molar ratio of the triol to the alkali metal is 1:3.5 to 1:

6. The alkali metal includes one or more of lithium, sodium, and potassium.

8. The preparation method according to claim 5, characterized in that: In the step a), the ratio of the molar amount of the chloromethyl salicylaldehyde compound to the total molar amount of the diol metal compound and the triol metal compound is 2:1-4:1; the molar ratio of the diol metal compound to the triol metal compound is 100:0.5-20; the reaction temperature is 20-110°C, and the reaction time is 2-48h; In the step b), the ratio of the total molar amount of the disalicylicylaldehyde compound and the trisalicylicylaldehyde compound to the molar amount of the diamino compound is 1:0.6-1.5; the reaction temperature is 20-100°C, and the reaction time is 1-48h; In the step c), the metal compound includes at least one of zinc chloride, zinc acetate, ethyl zinc, stannous chloride, ferric chloride, indium chloride, cobalt acetate, aluminum isopropoxide, aluminum ethoxide, nickel acetate and triethylaluminum; the molar ratio of the diamino compound residue in the branched Schiff base polymer to the metal compound is 1:1 to 1:1.2; the reaction temperature is 20 to 120° C., and the reaction time is 2 to 100 hours.

9. Use of the branched polymeric Schiff base metal compound according to any one of claims 1 to 4 or the branched polymeric Schiff base metal compound prepared by the preparation method according to any one of claims 5 to 8 as a catalyst in the preparation of poly(lactide-glycol).

10. A method for preparing poly(lactide-glycol) comprising: The following steps are involved: In an inert atmosphere, glycolide and lactide, or glycolide, lactide and an epoxy compound are reacted in the presence of a catalyst and an initiator to obtain poly(glycol-lactide); The catalyst is the branched polymeric Schiff base metal compound described in any one of claims 1 to 4 or the branched polymeric Schiff base metal compound prepared by the preparation method described in any one of claims 5 to 8.

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