US 8,709,376 B2  40  39  TABLE 20  TABLE 21  TABLE22  Example 49  Extraction of Sulfuric Acid from Aqueous Glycolic  Acid  Feed Conditions for Continuous Back Extractions with Aqueous Formaldehyde  Agit. Rate  Mass S/F  Feed Flow  Feed Wt%  Ex. Feed  Strokes/min  Ratio  43 sulfuric acid-rich  310  1.45  extract  44 Extract Example 3 6  310  2.76  45 Extract Example 37  300  2.89  46 Extract Example 3 7  327  2.23  47 Extract Example 3 7  327  1.49  48 Extract Example 3 8  332  0.495  Solvent Flow  g/min  11.4  11.4  7.6  7.6  7.6  22.8  H$_{2}$SO$_{4 }$ 2.59%  2.21%  1.99%  1.99%  1.99%  1.87%  GAOlig.  0.93%  0.45%  0.49%  0.49%  0.49%  0.51%  Ex.  TEHA  2-EHA  Heptane  g/min  Solv. wt% (aq. HFr)  water  43  44  45  46  47  48  9.33%  36.5%  50.65%  16.5  49.00%  7.38%  29.1%  60.89%  31.5  45.00%  7.54%  26.3%  63.71 %  22.0  42.00%  7.54%  26.3%  63.71 %  17.0  49.00%  7.54%  26.3%  63.71 %  11.3  42.00%  7.41%  27.7%  62.49%  11.3  49.90%  51%  55%  58%  51%  58%  50.1%  Ex.  43  44  45  46  47  48  Results for Continuous Back Extractions  with Agueous Formaldehyde  Recovery to Formaldehyde  Extract Product  Glycolic  Recovery to Raffinate Product  H2SO4  Oligomers  Amine  Heptane  2-EHA  98.4%  100.0%  98.8%  100.0%  95.3%  99.8%  100.0%  99.0%  100.0%  100.0%  99.4%  100.0%  100.0%  100.0%  94.7%  98.8%  100.0%  98.0%  100.0%  94.4%  98.8%  100.0%  98.0%  100.0%  94.4%  98.7%  99.8%  100.0%  99.5%  Sulfuric acid was added to a 85 wt% glycolic acid-15 wt%  water mixture to produce a solution comprising 3 wt% sul› furic acid. Extraction solvents were prepared by mixing an  amine and diluents(s) as specified in Table 22. Five grams of  each amine solvent solution was mixed with five grams of the  sulfuric acid-aqueous glycolic acid mixture and allowed  equilibrate at the temperature specified in Table 22. If two  phases resulted, samples of each phase were analyzed by  x-ray for sulfur content and converted into a sulfuric acid  concentration in each phase (grams of sulfuric acid per gram  of amine phase and grams of sulfuric acid per gram of aque› ous glycolic acid phase).  Extraction of Sulfuric Acid from Agueous Glycolic Acid  Wt%  Wt%  Wt%  Acid/  Acid/  Amine  Diluent 1  Diluent2  Amine  D1  D2  T, CC.  Phases  GA  Amine  TEHA  n-Octanol  none  35%  65%  0%  40  n/a  TEHA  2-Ethylhexanol  none  35%  65%  0%  40  2  0.0012  0.0290  TEHA  Heptane  none  35%  65%  0%  40  2  0.0132  0.0125  TEHA  2-Heptanone  none  35%  65%  0%  40  n/a  Alamine  n-Octanol  none  35%  65%  0%  40  2  0.0004  0.0286  336  Alamine  2-Ethylhexanol  none  35%  65%  0%  40  2  0.0006  0.0290  336  Alamine  Heptane  none  35%  65%  0%  40  3  n/a  336  Alamine  2-Heptanone  none  35%  65%  0%  40  2  0.0003  0.0288  336  TEHA  2-EHA  none  35%  65%  0%  40  2  0.0012  0.0260  TEHA  2-EHA  Heptane  35%  32.5%  32%  40  2  0.0019  0.0264  TEHA  Laurie acid  none  35%  65%  0%  40  2  0.0011  0.0244  TEHA  2-Heptanone  Heptane  35%  32.5%  32%  40  3  n/a  TEHA  Dibutylether  none  35%  65%  0%  40  3  n/a  TEHA  Toluene  none  35%  65%  0%  40  3  n/a  Alamine  2-EHA  none  35%  65%  0%  40  2  0.0005  0.0276  336  Alamine  Toluene  none  35%  65%  0%  40  2  0.0001  0.0278  336  TEHA  2-EHA  none  35%  65%  0%  80  2  0.0017  0.0282  TEHA  2-EHA  Heptane  35%  32.5%  32%  80  2  0.0055  0.0230  TEHA  Laurie acid  none  35%  65%  0%  80  2  0.0018  0.0198  TEHA  2-Heptanone  Heptane  35%  32.5%  32%  80  3  n/a 