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CN-121975125-A - Method for synthesizing phenolic hydroxyl modified polysiloxane by using phenolic hydroxyl protection-deprotection two-step method

CN121975125ACN 121975125 ACN121975125 ACN 121975125ACN-121975125-A

Abstract

The application relates to the technical field of chemical synthesis, and particularly discloses a method for synthesizing phenolic hydroxyl modified polysiloxane by a phenolic hydroxyl protection-deprotection two-step method. The method comprises the steps of S1, protecting phenolic hydroxyl groups, S2, hydrosilylation, namely, under the action of a platinum catalyst, carrying out addition reaction on the phenolic hydroxyl groups and hydrogen-containing silicone oil in an organic solvent to obtain protective phenolic hydroxyl group modified polysiloxane, S3, deprotecting, namely, adding a deprotecting reagent into the protective phenolic hydroxyl group modified polysiloxane to carry out reaction, and separating and purifying to obtain the phenolic hydroxyl group modified polysiloxane. The application obviously improves the selectivity of the hydrosilylation reaction and the yield of the product, has low content of free phenol in the product, has the weather resistance of organosilicon and the reactivity of phenolic hydroxyl, and can be widely applied to a plurality of fields.

Inventors

  • ZHU GUOJIAN

Assignees

  • 江西亮华科技有限公司

Dates

Publication Date
20260505
Application Date
20260320

Claims (10)

  1. 1. The method for synthesizing the phenolic hydroxyl modified polysiloxane by using the phenolic hydroxyl protection-deprotection two-step method is characterized by comprising the following steps of: S1, protecting phenolic hydroxyl groups, namely selectively protecting hydrogen atoms in the phenolic hydroxyl groups by using unsaturated olefin phenol as a raw material under the protection of inert gas to obtain phenolic hydroxyl group-protected olefin phenol intermediates, wherein the protective agent is one of trimethylchlorosilane, tert-butyldimethylsilyl chloride or acetyl chloride; S2, hydrosilylation, namely under the action of a platinum catalyst, carrying out addition reaction on a phenolic hydroxyl protected olefin phenol intermediate and hydrogen-containing silicone oil in an organic solvent to obtain protected phenolic hydroxyl modified polysiloxane; S3, deprotection, namely adding a deprotection reagent into the protected phenolic hydroxyl modified polysiloxane for reaction, washing with water, separating liquid, and distilling under reduced pressure to obtain the phenolic hydroxyl modified polysiloxane, wherein the deprotection reagent is one of hydrochloric acid aqueous solution, sodium hydroxide aqueous solution or trifluoroacetic acid.
  2. 2. The method for synthesizing a phenolic hydroxyl modified polysiloxane according to claim 1, wherein in step S1, the molar ratio of the unsaturated olefin phenol to the protecting agent is 1 (1.0-1.5).
  3. 3. The method for synthesizing a phenolic hydroxyl group-modified polysiloxane according to claim 1, wherein in step S1, the reaction condition of the phenolic hydroxyl group protection is that the reaction is carried out for 2 to 8 hours at a temperature of 20 to 60 ℃.
  4. 4. The method for synthesizing a phenolic hydroxyl modified polysiloxane according to the two-step phenolic hydroxyl protection-deprotection method of claim 1, wherein in step S2, the molar ratio of Si-H bond to c=c bond of the phenolic hydroxyl protected olefinic phenol intermediate to the hydrogen-containing silicone oil is 1 (1.0-1.2).
  5. 5. The method for synthesizing a phenolic hydroxyl modified polysiloxane according to claim 1, wherein in step S2, the hydrosilylation reaction condition is that the reaction is carried out for 4 to 12 hours at a temperature of 80 to 120 ℃.
  6. 6. The method for synthesizing a phenolic hydroxyl modified polysiloxane according to claim 1, wherein in step S2, the platinum-based catalyst is one of a chloroplatinic acid isopropyl alcohol solution, a Karstedt catalyst, or a Speier catalyst.
  7. 7. The method for synthesizing phenolic hydroxyl modified polysiloxane by adopting the two-step method for protecting and deprotecting phenolic hydroxyl according to claim 1, wherein in the step S2, an antioxidant is added into the reaction system of the hydrosilylation reaction, the dosage of the antioxidant is 0.1-0.5% of the total mass of the raw materials of the reaction system, and the antioxidant is one or more of 2, 6-di-tert-butyl-p-cresol (BHT) or other hindered phenol antioxidants.
  8. 8. The method for synthesizing a phenolic hydroxyl modified polysiloxane according to claim 1, wherein in step S3, the deprotection reaction condition is that the reaction is carried out for 1 to 6 hours at a temperature of 20 to 80 ℃.
  9. 9. The method for synthesizing phenolic hydroxyl modified polysiloxane by adopting the two-step method for protecting and deprotecting phenolic hydroxyl according to claim 1, wherein in the step S3, the temperature of reduced pressure distillation is 90-110 ℃, the pressure is 0.092-0.098MPa, the time is 40-80min, the residual amount of low-boiling-point substances in a target product is less than or equal to 0.5%, and the residual amount of solvents is less than or equal to 0.05%.
  10. 10. The method for synthesizing a phenolic hydroxyl modified polysiloxane according to claim 1, wherein the phenolic hydroxyl modified polysiloxane comprises two structures of formula (I) and formula (II), wherein formula (I) is Formula (II) is 。

Description

Method for synthesizing phenolic hydroxyl modified polysiloxane by using phenolic hydroxyl protection-deprotection two-step method Technical Field The application relates to the technical field of chemical synthesis, in particular to the field of synthesis of phenolic hydroxyl modified polysiloxane, and more particularly relates to a method for synthesizing phenolic hydroxyl modified polysiloxane by a phenolic hydroxyl protection-deprotection two-step method. Background The phenolic hydroxyl modified polysiloxane (such as phenol propyl polysiloxane) has important application value in the fields of resin modification, coating, flame retardant materials and the like because the phenolic hydroxyl modified polysiloxane has the reactivity of phenolic hydroxyl and the characteristics of weather resistance, temperature resistance and the like of polysiloxane. In the prior art, the synthesis of the products adopts a process route of direct hydrosilylation of phenolic monomers and hydrogen-containing polysiloxane, however, the chemical characteristics of phenolic hydroxyl groups and the system characteristics of the polysiloxane are mutually restricted, so that the traditional route has inherent defects which cannot be overcome, and the method is specifically shown as follows: (1) The arc pair electron of the phenolic hydroxyl group is easy to carry out strong complexation with Pt/Pd noble metal catalyst used in hydrosilylation reaction, so that the catalyst is deactivated rapidly, the use level of the catalyst is required to be greatly increased to be improved, the process cost is obviously increased, meanwhile, the phenolic hydroxyl group is easy to be oxidized into quinone byproducts in a reaction system, or non-target side reaction with silicon hydrogen bond is carried out to generate phenoloxysilane, the effective phenolic hydroxyl group content in the product is only 60-80%, the functional group selectivity and the product purity are lower, and the yield is poor (generally less than or equal to 80 percent); (2) The compatibility of the phenolic monomer (polarity) and the hydrogen-containing polysiloxane (nonpolar) is poor, local agglomeration is easy to occur in the direct addition reaction, side reactions such as polysiloxane main chain depolymerization and crosslinking are initiated, the content of free phenol in the product is excessively high (more than or equal to 1.0%), and the core performance stability such as reactivity and compatibility in the subsequent application is poor; (3) In order to relieve the side reaction of phenolic hydroxyl groups, a large amount of polymerization inhibitor and antioxidant are added in the prior art, so that the cost is further increased, new impurities are introduced, byproducts such as quinones, phenoloxysilane and the like generated after the reaction are difficult to remove efficiently, and the residual impurities can obviously deteriorate the heat resistance and the reaction activity of the product, so that the application of the product in the middle-high end field is limited; (4) The traditional direct addition route has extremely poor suitability for phenolic monomers, can be only suitable for simple phenols with low steric hindrance and weak polarity, and can hardly meet diversified product requirements for large-steric-hindrance phenols and polyhydroxy phenols due to aggravated phenolic hydroxyl side reaction and poorer compatibility, and almost realizes effective synthesis. Aiming at the problems, the prior art also researches and tries to improve the reaction effect by adjusting the reaction temperature, optimizing the catalyst ratio, adding a cosolvent and other conventional means, but the conventional methods are local microinnovations of the conventional route, the methods not only increase the production cost, but also can possibly cause the new problems of cross-linking of silicone oil, deepening of the color of the product and the like, and the other proposal adopts an indirect route that phenolic hydroxyl groups are etherified first and then hydrolyzed, but the process steps are complicated, and the main chain of the siloxane is easy to break in the hydrolysis process. Disclosure of Invention In order to solve the technical problems and overcome the inherent defects of a direct hydrosilylation route in the prior art, the application provides a method for synthesizing phenolic hydroxyl modified polysiloxane by a phenolic hydroxyl protection-deprotection two-step method. The core of the method is a closed-loop process route of selective protection of phenolic hydroxyl groups, hydrosilylation and precise deprotection, and the cross-field fusion of an organic synthesis protecting group technology and an organic silicon synthesis technology is adopted, so that the core contradiction between the side reaction of the phenolic hydroxyl groups and the compatibility of a polysiloxane system is fundamentally solved, and the preparation targets of high purity, con