Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/28—Oxygen or compounds releasing free oxygen
  • C08F4/32—Organic compounds
  • C08F4/38—Mixtures of peroxy-compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F126/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
  • C08F126/06—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen by a heterocyclic ring containing nitrogen
  • C08F126/10—N-Vinyl-pyrrolidone
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F6/00—Post-polymerisation treatments
  • C08F6/001—Removal of residual monomers by physical means
  • C08F6/003—Removal of residual monomers by physical means from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom

Definitions

• the invention relates to the technical field of compound synthesis, in particular to the technical field of homopolymerization of N-vinyl butyrolactam, in particular to a method for synthesizing a high-molecular-weight homopolymerized N-vinyl butyrolactam K60 aqueous solution in a low residual single. Background technique
• Homopolymerized N-vinyl butyrolactam is a very important water-soluble polymer which is polymerized by N-vinyl butyrolactone under certain conditions (Yan Ruizhen. Water-soluble polymer 2nd Edition [M]. Beijing: Chemical Industry Press, 2010, 217).
• K60 is a medium-high molecular weight N-vinyl butyrolactam polymer, which combines the properties of low molecular weight homopolymeric N-vinyl butyrolactam with high molecular weight homopolymerized N-vinyl butyrolactam. prospect.
• Homopolymerized N-vinyl butyrolactam is widely used due to its unique properties. It not only has excellent solubility, chemical stability, film formation, physiological inertness, bonding ability and protective rubber action, but also It is combined with many inorganic and organic compounds. Therefore, homopolymerized N-vinyl butyrolactam has been widely used in medicine, cosmetics, food, brewing, coatings, adhesives, printing and dyeing auxiliaries, separation membranes, and sensitization. Materials and other fields. With the development of science and technology, the application of homopolymerized N-vinyl butyrolactam has become more and more widely used in high-tech fields such as photo-curable resins, optical fibers, laser discs, and drag reducing materials.
• Lactam is used in the field of dye sensitized batteries that are now very popular.
• K60 is a medium-high molecular weight N-vinyl butyrolactam polymer, which combines the properties of low molecular weight homopolymeric N-vinyl butyrolactam with high molecular weight homopolymeric N-vinyl butyrolactam, while medium and high molecular weight is difficult to produce.
• the reasons are as follows: (1) The polymerization of N-vinyl butyrolactam is a chain reaction, and it is difficult to terminate once the reaction starts, and the K value is difficult to control; (2) There is also inhibition in the N-vinyl butyrolactam monomer. The agent causes the residual monomer to be too high; (3) Reducing the residual unreacted raw material content increases the cost, and the additional operation is difficult. Therefore, this technology is only mastered by BASF in Germany, and there is no report on K60 products in China.
• the content of unreacted monomeric N-vinyl butyrolactam in pharmaceutical or food grade homopolymerized N-vinyl butyrolactam is less than 10 ppm.
• homopolymerized N-vinylbutene Amide industrial production of multi-polymer polymer post-treatment processes such as activated carbon adsorption, solvent extraction or ultrafiltration, radiation, etc.
• the object of the present invention is to overcome the above-mentioned shortcomings of the prior art and to provide a method for synthesizing a high-molecular-weight homopolymeric N-vinyl butyrolactam K60 aqueous solution in a low-residue single-molecular high-molecular-weight homopolymer N-vinyl group.
• the synthesis method of butyrolactam K60 aqueous solution is ingeniously designed to prepare a single sheet, and the residual residue of the high-molecular-weight homopolymer N-vinyl butyrolactam K60 aqueous solution prepared in the low residual single is below 10 ppm, K value is 58-65, suitable for large Scale promotion application.
• a method for synthesizing a low-residue high-molecular-weight homopolymerized N-vinyl butyrolactam K60 aqueous solution of the present invention is characterized in that, in the presence of an inert gas, 20 to 50% by weight of N-vinyl is used.
• the aqueous solution of butyrolactam monomer is used as a raw material.
• the reaction Under the polymerization temperature of 57 ° C to 72 ° C, the reaction is stirred for 4-6 hours, and the initiator is added stepwise, and the initiator is azobisisoheptanenitrile.
• the amount of the initiator is 0.01 ⁇ 2% of the mass of the N-vinyl butyrolactam monomer, and the K value of the system is 58 ⁇ 65, and the H is added to the sulfuric acid to adjust the H to 4.2 ⁇ 4.5 at a temperature of 90-140 °C.
• the residue is eliminated over a period of time to obtain a 20 to 50% by weight aqueous solution of a high molecular weight homopolymeric N-vinyl butyrolactam K60 having a residual color of less than 10 ppm and a K value of 58 to 65.
• the step of raising and decreasing the addition of the initiator may be carried out by any suitable step.
• the step of raising and decreasing the addition of the initiator is specifically carried out by the following steps: first adding 40% of the total weight of the initiator at 57 ° C ⁇ 60%, start polymerization, after 2h, add 10 ⁇ 30% of the total weight of the initiator at 62 °C, continue to react for 1h, add 10-30% of the total weight of the initiator at 72 °C, continue the reaction -3h.
• the sulfuric acid may be added in any suitable manner, and preferably, the sulfuric acid is added as a 50% sulfuric acid solution.
• the temperature of the heat-insulated stirring elimination residue can be selected as needed. Preferably, the temperature of the heat-insulated stirring elimination residue is 90 ° C, 120 ° C or 140 ° C.
• the incubation time is generally 4 hours or longer. Preferably, the incubation time is 4-12 hours.
• the beneficial effects of the present invention are specifically as follows: the method for synthesizing the high-molecular-weight homopolymerized N-vinyl butyrolactam K60 aqueous solution in the low residual single sheet of the present invention is 20-50% by weight of N-vinyl in the presence of an inert gas.
• the aqueous solution of butyrolactam monomer is used as a raw material.
• the polymerization temperature is 57 ° C -72 ° C, the reaction is stirred for 4-6 hours, the temperature is increased in stages, and the initiator is added.
• the initiator is azobisisoheptonitrile, and the total is added.
• the amount of the initiator is 0.01 to 2% of the mass of the N-vinyl butyrolactam monomer.
• the K value of the system reaches 58 ⁇ 65, and the sulfuric acid is adjusted to 4.2 ⁇ 4.5.
• the temperature is stirred at 90-140 °C for 4 hours or more to eliminate the residual, so that 20 ⁇ 50% of the residuals are below lOppm and the K value is obtained. It is a colorless and transparent low-residue single-color high-molecular-weight homopolymerized N-vinyl butyrolactam K60 aqueous solution of 58 ⁇ 65.
• N-vinyl butyrolactam Industrial grade (decompression distillation) Shanghai Yuang Chemical Technology Development Co., Ltd. Azobisisobutyronitrile (AIBN) Chemically pure Shanghai Test Sihewei Chemical Co., Ltd.
• N-vinyl butyrolactam monomer aqueous solution 20 ⁇ 50% N-vinyl butyrolactam monomer aqueous solution was used, water and N-vinyl butyrolactam monomer were first added to a three-necked flask, placed in a constant temperature oil bath, and protected by N 2 Under the polymerization temperature of 57 °C -72 °C, the reaction is stirred for 4-6 hours, and the initiator is added in increments of 0.01 ⁇ 2%, and the K value of the system is 58 ⁇ 65.
• K value of the Fikentscher formula is a parameter that is only related to molecular weight and does not change with the concentration of homopolymeric N-vinyl butyrolactam.
• a commonly used method for determining the K value is a viscosity method.
• the Ubbel viscometer measures the relative viscosity r) r of the solution against water at a water bath temperature of 25 ⁇ 0.2 °C.
• K is the Fikentscher constant
• C is the number of grams of homopolymerized N-vinyl butyrolactam dissolved in 0.1 L solution
• ⁇ ⁇ is the relative viscosity (the ratio of solution effluent time to pure solvent efflux time ⁇ / ⁇ 0 )
• the determination of the residual monomer content in the homopolymerized fluorene-vinyl butyrolactam is based on the method specified in the 26th edition of the United States Pharmacopoeia. Take 10g of homopolyindole-vinyl butyrolactam (accurate to 0.002g, based on anhydrous matter), dissolve in 80ml of distilled water, add lg sodium acetate, titrate with 0.1 mol/L iodine solution until the solution no longer fades, then Add 3 ml of 0.1mol/L iodine solution for 10 minutes, then titrate excess iodine with 0.1 mol/L sodium thiosulfate. Add 3 ml of starch indicator when approaching the end point, continue titration until the solution color disappears. At the same time, compared with the blank experiment.
• This experiment mainly studies solution polymerization, using different initiators for polymerization, using a variety of initiator systems, such as: hydrogen peroxide (3 ⁇ 40 2 ), t-butyl hydroperoxide, benzoyl peroxide; Redox system, such as: ammonium tetrahydrogenate monosodium hydride; azo, such as: azobisisobutyronitrile, azobisisoheptanenitrile. The effect of these systems on the content of residual unreacted raw materials was tested separately.
• initiator systems such as: hydrogen peroxide (3 ⁇ 40 2 ), t-butyl hydroperoxide, benzoyl peroxide; Redox system, such as: ammonium tetrahydrogenate monosodium hydride; azo, such as: azobisisobutyronitrile, azobisisoheptanenitrile.
• ROOR represents a peroxide
• R represents an organic group
• 0 is an oxygen atom
• reaction conditions are: temperature 75 ° C, 50 ml N-vinyl butyrolactam (NVP) monomer, 200 ml water meter 2 shows that neither 3 ⁇ 40 2 nor t-butyl hydroperoxide can initiate polymerization, 3 ⁇ 40 2 in alkali
• N-vinyl butyrolactam (NVP) monomer 200 ml water meter 2 shows that neither 3 ⁇ 40 2 nor t-butyl hydroperoxide can initiate polymerization, 3 ⁇ 40 2 in alkali
• N-vinyl butyrolactam (NVP) monomer 200 ml water meter 2 shows that neither 3 ⁇ 40 2 nor t-butyl hydroperoxide can initiate polymerization, 3 ⁇ 40 2 in alkali
• intermediates such as hydrogen peroxy anion, hydroxyl radical, hydroxy anion, etc.
• 3 ⁇ 40 2 still does not initiate, and ammonia can quickly cause 3 ⁇ 40 2 to initiate, therefore, the choice of 3 ⁇ 40 2 activator plays an important role in its initiation.
• t-butyl hydroperoxide has a high initiation efficiency in the presence of Cu 2+ . Therefore, t-butyl hydroperoxide also needs to find a suitable activator. For benzoyl peroxide, it can be initiated without the need for an activator, but the residual unreacted raw material obtained is relatively high in content and the reaction time is relatively long.
• ammonium persulfate-sodium bisulfite redox system when the mass ratio of ammonium persulfate: sodium bisulfite is 2.0216: 0.8796 (molar ratio is greater than 1), the reaction viscosity is unchanged for 24 hours, the system fails to trigger When the mass ratio of o is 4.6142: 0.5125 (molar ratio is about 4:1), the color of the system is red, and the system fails to be triggered in 24 hours.
• Fikentscher first developed an aqueous solution polymerization method for N-vinyl butyrolactam. When it was initiated with an azo initiator, the polymerization mechanism was as follows:
• RN ⁇ NR represents an azo initiator
• R represents an organic group
• N is a nitrogen atom
• the homopolymerized N-vinyl butyrolactam studied in this invention is pharmaceutical grade and food grade, and has low toxicity. The requirements are higher.
• the choice of initiator can be found.
• the redox system is not suitable for the preparation of homopolymeric N-vinyl butyrolactam K60, while the peroxide should consider the choice of activator, the system is more complicated, and azo, The system is simple, the reaction temperature is low, the initiation efficiency is high, and the residual unreacted raw material content is low.
• ABVN has more advantages than AIBN, so our initiator uses ABVN.
• the initiator is added in multiple stages, and the polymerization temperature is increased in the later stage of polymerization.
• the polymerization process was as follows: Using AVBN at 54 ° C, the reaction was first carried out for 1 hour, then AVBN was added, the temperature was raised to 75 ° C, and the reaction was observed at 75 ° C to observe the viscosity change. When the K value was about 60, the acid was adjusted to pH. Between 3-5, the temperature was raised to 80 ° C, and the mixture was stirred for 12 hours.
• the best initiator for the homopolymerization of N-vinyl butyrolactam K60, which has a very low residual unreacted raw material content, is azobisisoheptanenitrile (ABVN).
• ABSVN azobisisoheptanenitrile
• the polymerization process uses a special segmental high temperature, which increases with temperature.
• the method of reducing the dosage of the additional dosage is carried out by using sulfuric acid to adjust the pH 4.2-4.5 at a high temperature of 90-140 ° C for more than 4 hours, so that the residue can be effectively reduced even if the residual residue treatment process such as methylene chloride precipitation is not used.
• the amount of residual unreacted raw materials is less than 0.001% as specified in USP 32.
• the invention will be more specifically illustrated by the following examples, but the invention is not limited by these examples. In the following, unless otherwise stated, "parts by weight” is only expressed as “parts”, and “% by weight” is only expressed as "%”.
• Example 2 The difference from Example 1 is as follows: After the addition of azobisisoheptanenitrile, the reaction is maintained at 72 ° C for 2 hours; the temperature of the oil bath is raised to 140 ° C, the temperature is maintained, and after stirring for 12 hours, the solid content is obtained. 20.3% of a colorless, transparent medium to high molecular weight homopoly N-vinyl butyrolactam K60 polymer solution. The K value of the product (measured as a 1% by weight aqueous solution) was 62.1, and the residual unreacted monomer N-vinyl butyrolactam content was below 10 ppm.
• Example 3 The K value of the product (measured as a 1% by weight aqueous solution) was 62.1, and the residual unreacted monomer N-vinyl butyrolactam content was below 10 ppm.
• the present invention adjusts the homopolymerization of N-vinyl butyl by studying the effect of different initiation systems and different polymerization processes on the residual monomer content in the solution polymerization process of homopolymerized N-vinyl butyrolactam K60.
• the polymerization process of lactam K60 gave a low residual single homopolymer N-vinyl butyrolactam K60.
• the method for synthesizing the high-molecular-weight homopoly-vinylbutyrolactam ⁇ 60 aqueous solution in the low-residue single-book of the present invention is ingeniously designed, and the prepared low-single medium-high molecular weight homopoly-vinyl butyrolactam ⁇ 60 is prepared.
• the residue of the aqueous solution is below 10 ppm and the K value is 58-65, which is suitable for large-scale popularization and application.

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