4IR Solutions
Amide Reactor Optimization
Amide
  • Presently, amide mixer and reactor samples from MM7, MM8 and MAA2 are analyzed offline via high performance liquid chromatography (HPLC). Values obtained from this analysis include conversion index (CI), water balance and decomposition index (DI).
  • Recent requirements for amide reactors have created a need for a continuous optimization, which will ensure that reactors run at consistently high efficiencies and give the maximum possible output.
  • There are several drawbacks that limit the analysis for optimization purposes:
  • Frequency of data collection – Currently 1-2 samples are collected and analyzed every 24 hour period per reactor. This low rate of data collection severely limits the rate with which the reactors can be optimized and is insufficient.
  • Offline sampling – There are difficulties in the handling of amide mixture samples. Furthermore, the sample composition is prone to change post-sampling.
  • Delay – It will often be a matter of hours before HPLC data are fed back for response of the technical team.
  • Reliability – Being high in sulfuric acid and sensitive to moisture, the nature of the samples makes them difficult to analyze by HPLC.
  • Spectral processing facilitates use of a variety of chemometric based routines for multiple property measurements.
AI-60 in Amide Reactor Optimization
  • Proton NMR Spectroscopy technique offers numerous advantages:
  • A major advantage of 1H NMR is that individual scans only require a matter of seconds to collect. Several scans may be required to obtain a reliable, composite spectra.
  • Online analysis – 1H NMR does not need to come into physical contact with samples and therefore lends itself to being adapted to online analysis. Thus all the problems associated with physical sampling can be circumvented.
  • Reliability - 1H NMR is inherently quantitative as it measures the relative signals from hydrogen nuclei (protons) present on each of the molecules in the mix, given that complete relaxation of these nuclei is allowed to occur. The relative ratios of components can therefore be accurately determined from first principles, without the need for continuous calibration.
Results and Discussion (I)
  • When reviewing the 1H NMR spectrum of MAM in DMSO-d6, a large singlet is observed at 1.60 ppm with an integral of 3, this signal originates from the 3 methyl protons. Two signals occurring at 5.11 and 5.46 ppm respectively and each integrating for a single proton are assigned to the 2 methylene protons. A broad doublet is observed at 6.81 ppm and is assigned to the 2 amide protons.
  • Reference Spectra of MAM
Results and Discussion (II)
  • When reviewing the 1H NMR spectrum of MAM in H2SO4, the HsSO4 contributes a large singlet peak at 11.22 ppm but otherwise many of the same features are present. All signals have shifted downfield, the methyl singlet to 2.20 ppm, the two methylene singlets to 6.29 and 6.62 ppm respectively and the broad amide singlet to 8.20 ppm.
  • Reference Spectra of MAM
Results and Discussion (III)
  • When reviewing the 1H NMR spectrum of MAA in DMSO-d6, a large singlet is observed at 1.26 ppm with an integral of 3, this signal originates from the 3 methyl protons. Two signals occurring at 4.98 and 5.56 ppm respectively and each integrating for a single proton are assigned to the 2 methylene protons. The singlet at 12.10 ppm is assigned to the carboxylic acid proton.
  • Reference Spectra of MAM
Results and Discussion (IV)
  • When reviewing the 1H NMR spectrum of MAA in H2SO4, many of the same features are present. Similar to MAM, all signals have shifted downfield, the methyl singlet to 2.13 ppm, the two methylene singlets to 6.45 and 6.89 ppm respectively and the carboxylic acid singlet has presumably disappeared beneath the H2SO4 peak.
  • Reference Spectra of MAM
Results and Discussion (V)
  • When reviewing the 1H NMR spectrum of SIBAM in DMSO-d6, a large singlet is observed at 0.94 ppm; this signal is assigned to the 6 chemically equivalent methyl protons with an integral of 6. A broad singlet is present at 9.56 ppm, which is tentatively assigned to the 2 amide protons but the integral is difficult to determine due to the broad peak shape.
  • Reference Spectra of MAM
Results and Discussion (VI)
  • When reviewing the 1H NMR spectrum of SIBAM in H2SO4, the methyl singlet appears to have been shifted downfield and now occurs at 1.94 ppm. Finally, the broad amide doublet can be seen at 8.86 ppm but is poorly resolved from the large, sulfuric acid singlet. Tal, both up field ‘singlets’ could be from the methyl groups, the solvent could have induced some in equivalence.
  • Reference Spectra of MAM