Online monitoring of polymerization inhibitors for control of undesirable polymerization

Patent metadata

Field	Value
Publication number	US-9266797-B2
Application number	US-201313765508-A
Country	US
Kind code	B2
Filing date	Feb 12, 2013
Priority date	Feb 12, 2013
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

Disclosed herein are systems and methods for monitoring and controlling a nitroxide-based polymerization inhibitor in vinyl-based monomers. A dosage of the nitroxide-based polymerization inhibitor is provided in the vinyl-based monomers. A residual concentration of the nitroxide-based polymerization inhibitor is measured substantially in real time, and an optimized dosage of the nitroxide-based polymerization inhibitor is provided in response to the measured residual concentration.

First claim

What is claimed is:

1. A method of monitoring and controlling a single nitroxide-based polymerization inhibitor in vinyl-based monomers, the method comprising:
providing a dosage of the single nitroxide-based polymerization inhibitor in the vinyl-based monomers;
measuring a residual concentration of the single nitroxide-based polymerization inhibitor substantially in real time; and
providing an optimized dosage of the single nitroxide-based polymerization inhibitor in response to the measured residual concentration.

2. The method of claim 1 , wherein the residual concentration is measured on a substantially continuous basis.

3. The method of claim 1 further comprising providing a fast flow sampling loop, and wherein the residual concentration of the single nitroxide-based inhibitor is measured after the fast flow sampling loop.

4. The method of claim 3 , wherein after the fast flow sampling loop resides a continuous stirred tank reactor and an apparatus for providing the optimized dosage of the single nitroxide-based inhibitor into the continuous stirred tank reactor and wherein the residual concentration of the single nitroxide-based inhibitor is measured from the contents of the continuous stirred tank reactor.

5. The method of claim 1 further comprising evaluating a degree of undesirable polymerization in the vinyl-based monomer based on the measured residual concentration.

6. The method of claim 5 , wherein the degree of undesirable polymerization is evaluated using at least one of an electron spin resonance spectrometer, a gas chromatograph, a gas chromatograph-mass spectrometer, liquid chromatography, nuclear magnetic resonance, x-ray diffraction, x-ray fluorescence, atomic absorption, inductively coupled plasma emission spectroscopy, an ultraviolet-visible spectrometer, an infrared spectrometer, a near-infrared spectrometer, a Raman spectrometer, a fluorometer, a turbidimeter, dynamic light scattering, evaporative light scattering, and a titrator.

7. The method of claim 5 further comprising co-dosing one or more retarders and/or antioxidants to the vinyl-based monomers and evaluating an effect of the co-dosed retarders and/or antioxidants on the degree of undesirable polymerization based on the measured residual concentration.

8. The method of claim 7 , wherein the effect of the co-dosed retarders and/or the antioxidants is evaluated using at least one of an electron spin resonance spectrometer, a gas chromatograph, a gas chromatograph-mass spectrometer, liquid chromatography, nuclear magnetic resonance, x-ray diffraction, x-ray fluorescence, atomic absorption, inductively coupled plasma emission spectroscopy, an ultraviolet-visible spectrometer, an infrared spectrometer, a near-infrared spectrometer, a Raman spectrometer, a fluorometer, a turbidimeter, dynamic light scattering, evaporative light scattering, and a titrator.

9. The method of claim 8 , wherein at least one of the co-dosed retarders is non-nitroxide-based.

10. The method of claim 1 , wherein the optimized dosage is so determined as to control an undesirable polymerization of the vinyl-based monomer during manufacture and purification thereof.

11. The method of claim 1 , wherein the single nitroxide-based polymerization inhibitor is 2,2,6,6-tetramethyl-4-hydroxypiperidin-1-oxyl.

12. A method of monitoring and controlling a nitroxide-based polymerization inhibitor in vinyl-based monomers, the method consisting of:
providing a dosage of a polymerization inhibitor in the vinyl-based monomers, wherein the polymerization inhibitor consists of a single nitroxide-based polymerization inhibitor;
measuring a residual concentration of the single nitroxide-based polymerization inhibitor substantially in real time; and
providing an optimized dosage of the single nitroxide-based polymerization inhibitor in response to the measured residual concentration.

13. The method of claim 1 , further comprising evaluating a degree of undesirable polymerization in the vinyl-based monomer based on the measured residual concentration, wherein the degree of undesirable polymerization is evaluated using an electron spin resonance spectrometer.

Assignees

• Ecolab Usa Inc

Inventors

• Colorado Jr Ramon
• Lewis Vincent
• Geiger Robert A
• Hancock Jessica
• Neilson Andrew R

Classifications

• C08F2/38 Primary

  Polymerisation using regulators, e.g. chain terminating agents {, e.g. telomerisation} · CPC title

• C08F2438/02

  Stable Free Radical Polymerisation [SFRP]; Nitroxide Mediated Polymerisation [NMP] for, e.g. using 2,2,6,6-tetramethylpiperidine-1-oxyl [TEMPO] · CPC title

• C07C7/20 Primary

  Use of additives, e.g. for stabilisation · CPC title

• B01J19/002

  Avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by suppressing side-reactions · CPC title

• B01J2219/00254

  Formation of unwanted polymer, such as "pop-corn" · CPC title