Preparation method of high-molecular-weight polyacrylamide

Abstract

The invention provides a preparation method of high-molecular-weight polyacrylamide. The method includes the steps of performing segmented polymerization to acrylamide and an initiator in a high-pressure kettle with a supercritical CO2 medium to obtain high-molecular-weight polyacrylamide; and then performing supercritical CO2 fluid extraction to extract small-molecular monomers which are incompletely reacted to obtain high-purity polyacrylamide. The product is pure and is free of follow-up treatment. The reaction medium is toxic-free and environment-friendly. The preparation method is economic and practical, and is green and environment-friendly.

Description

technical field

[0001] The present invention relates to a kind of preparation method of polyacrylamine, more specifically, relate to a kind of using oxidation-reduction initiation system in supercritical CO 2 A method for preparing high-molecular-weight polyacrylamide in medium, and using supercritical fluid extraction technology to improve the purity of polyacrylamide. Background technique

[0002] Acrylamide (PAM) is an important class of water-soluble polymers. It has special physical and chemical properties. It is easy to obtain various modified products with branched chain or network structure through grafting or crosslinking. It is widely used in petroleum, Metal and chemical mining, water treatment, textile, paper and other industries. The current methods of synthesizing polyacrylamide mainly include aqueous solution polymerization, inverse emulsion polymerization, inverse microemulsion polymerization, suspension polymerization, precipitation polymerization and so on...

Examples

Embodiment 1

[0029]Add 12.10 g of acrylamide, 0.0005 g of azobisisobutylamidine hydrochloride, and 0.002 g of ammonium persulfate into a 100 ml autoclave; seal it and blow nitrogen for 10 minutes to exclude oxygen, then add 0.002 g of sodium bisulfite solution.

[0030] Fill with CO using a high pressure pump 2 Make it reach the critical state, carry out the polymerization reaction, the temperature is 0 ℃, the pressure is 14MPa, the reaction time is 8 hours; then reduce the temperature and reduce the pressure to obtain a white wet block, and the measured intrinsic viscosity is 19.54dl / g. Monomer content determination Acrylamide monomer residual 1.7%.

[0031] The intrinsic viscosity [η] in the present invention is the value measured according to GB12005.1-89 Acrylamide Copolymer Intrinsic Viscosity Determination Method, and this value is used to characterize the molecular weight of the polymer.

Embodiment 2

[0033] Add 12.10 g of acrylamide to a 100 ml autoclave, add 0.002 g of azobisisobutylamidine hydrochloride, and 0.002 g of ammonium persulfate; seal it and blow nitrogen for 10 minutes to exclude oxygen, then add 0.002 g of sodium bisulfite.

[0034] Fill with CO using a high pressure pump 2 Make it reach the critical state, carry out the polymerization reaction, the temperature is 0 ℃, the pressure is 14MPa, the reaction time is 8 hours; then reduce the temperature and reduce the pressure to obtain a white wet block, and the measured intrinsic viscosity is 14.26dl / g. Monomer content determination Acrylamide monomer residual 0.7%.

Embodiment 3

[0036] Add 12.10 g of acrylamide, 0.0005 g of azobisisobutylamidine hydrochloride, and 0.002 g of ammonium persulfate into a 100 ml autoclave; seal it and blow nitrogen for 10 minutes to exclude oxygen, then add 0.002 g of sodium bisulfite.

[0037] Fill with CO using a high pressure pump 2 Make it reach the critical state, carry out the polymerization reaction, the temperature is 0°C, the pressure is 14MPa, the reaction time is 8 hours; then the reactor is raised to 80°C and kept for 1 hour.

[0038] Then open the outlet valve and inject CO with a high-pressure pump 2 , keep the pressure at 11MPa, resolver temperature at 55°C, autoclave at 50°C, and slowly resolve the CO passing through the wet flowmeter 2 The flow rate is 40 liters (normal pressure state) / hour. Finally, while cooling, slowly depressurizing, the measured intrinsic viscosity of the product is 23.80dl / g. The monomer content was determined to be 0.03% of the residual acrylamide monomer.

technical field

[0001] The present invention relates to a kind of preparation method of polyacrylamine, more specifically, relate to a kind of using oxidation-reduction initiation system in supercritical CO 2 A method for preparing high-molecular-weight polyacrylamide in medium, and using supercritical fluid extraction technology to improve the purity of polyacrylamide. Background technique

[0002] Acrylamide (PAM) is an important class of water-soluble polymers. It has special physical and chemical properties. It is easy to obtain various modified products with branched chain or network structure through grafting or crosslinking. It is widely used in petroleum, Metal and chemical mining, water treatment, textile, paper and other industries. The current methods of synthesizing polyacrylamide mainly include aqueous solution polymerization, inverse emulsion polymerization, inverse microemulsion polymerization, suspension polymerization, precipitation polymerization and so on...

Examples

Embodiment 1

[0029]Add 12.10 g of acrylamide, 0.0005 g of azobisisobutylamidine hydrochloride, and 0.002 g of ammonium persulfate into a 100 ml autoclave; seal it and blow nitrogen for 10 minutes to exclude oxygen, then add 0.002 g of sodium bisulfite solution.

[0030] Fill with CO using a high pressure pump 2 Make it reach the critical state, carry out the polymerization reaction, the temperature is 0 ℃, the pressure is 14MPa, the reaction time is 8 hours; then reduce the temperature and reduce the pressure to obtain a white wet block, and the measured intrinsic viscosity is 19.54dl / g. Monomer content determination Acrylamide monomer residual 1.7%.

[0031] The intrinsic viscosity [η] in the present invention is the value measured according to GB12005.1-89 Acrylamide Copolymer Intrinsic Viscosity Determination Method, and this value is used to characterize the molecular weight of the polymer.

Embodiment 2

[0033] Add 12.10 g of acrylamide to a 100 ml autoclave, add 0.002 g of azobisisobutylamidine hydrochloride, and 0.002 g of ammonium persulfate; seal it and blow nitrogen for 10 minutes to exclude oxygen, then add 0.002 g of sodium bisulfite.

[0034] Fill with CO using a high pressure pump 2 Make it reach the critical state, carry out the polymerization reaction, the temperature is 0 ℃, the pressure is 14MPa, the reaction time is 8 hours; then reduce the temperature and reduce the pressure to obtain a white wet block, and the measured intrinsic viscosity is 14.26dl / g. Monomer content determination Acrylamide monomer residual 0.7%.

Embodiment 3

[0036] Add 12.10 g of acrylamide, 0.0005 g of azobisisobutylamidine hydrochloride, and 0.002 g of ammonium persulfate into a 100 ml autoclave; seal it and blow nitrogen for 10 minutes to exclude oxygen, then add 0.002 g of sodium bisulfite.

[0037] Fill with CO using a high pressure pump 2 Make it reach the critical state, carry out the polymerization reaction, the temperature is 0°C, the pressure is 14MPa, the reaction time is 8 hours; then the reactor is raised to 80°C and kept for 1 hour.

[0038] Then open the outlet valve and inject CO with a high-pressure pump 2 , keep the pressure at 11MPa, resolver temperature at 55°C, autoclave at 50°C, and slowly resolve the CO passing through the wet flowmeter 2 The flow rate is 40 liters (normal pressure state) / hour. Finally, while cooling, slowly depressurizing, the measured intrinsic viscosity of the product is 23.80dl / g. The monomer content was determined to be 0.03% of the residual acrylamide monomer.