US 8,785,686 B2  42  41  TABLE 20-continued  TABLE 19  TABLE21  TABLE 20  TABLE22  Results ofWash Extractions ofRaffinates from Continuous  Forward Extractions  Ex.  41  42  Amine  91.6%  87.0%  Heptane  99.97%  99.9%  2-EHA  93.1%  82.7%  Back Extractions of Sulfuric Acid-Rich Solvents in Con› tinuous Column-Sulfuric acid-rich extracts comprising sul› furic acid, TEHA, 2-ethylhexanoic acid, and heptane derived  from the forward extraction of hydrocarboxylation effluents  were fed to the continuous Karr column at a temperature of  70°  C. as described above and contacted with an aqueous  formaldehyde extraction solvent ( continuous phase). The sul› furic acid-rich extracts were introduced to the Karr column at  location F5 and the aqueous formaldehyde solvent was intro› duced at location Fl. Feed and solvent compositions, and  flow rates of the forward extraction experiments are summa- rized in Table 20. In each experiment, the column reached  steady state within an hour and was run continuously for six  to eight hours, with sampling occurring every one to two  hours. Averaged recoveries of TEHA, 2-ethylhexanoic acid,  and heptane to the raffinate product, and glycolic acid and  sulfuric acid to the formaldehyde extract product over the  time of steady state operation are given in Table 21.  Feed Conditions for Continuous Back  Extractions with Aqueous Formaldehyde  Agit.  Rate  Mass  Feed  Strokes/  S/F  Flow  Feed  Wt%  Ex. Feed  min  Ratio g/min H$_{2}$ SO$_{4 }$ GA  Olig.  43  sulfuric acid-rich  310  1.45  11.4  2.59%  extract  44 Extract Example 3 6  310  2.76  11.4  2.21%  45  Extract Example 3 7  300  2.89  7.6  1.99%  46 Extract Example 3 7  327  2.23  7.6  1.99%  47 Extract Example 3 7  327  1.49  7.6  1.99%  48 Extract Example 3 8  332  0.495  22.8  1.87%  0.93%  0.45%  0.49%  0.49%  0.49%  0.51%  Amine  TEHA  TEHA  TEHA  TEHA  Alamine  336  Alamine  336  Alamine  336  Alamine  336  TEHA  Diluent 1  n-Octanol  Extraction of Sulfuric Acid from Agueous Glycolic Acid  Wt%  Wt%  Wt%  T,  Acid/  Acid/  Diluent2  Amine  D1  D2  "C.  Phases  GA  Amine  none  35%  65%  0%  40  n/a  2-Ethylhexanol  none  35%  65%  0%  40  2  0.0012  0.0290  Heptane  none  35%  65%  0%  40  2  0.0132  0.0125  2-Heptanone  none  35%  65%  0%  40  n/a  n-Octanol  none  35%  65%  0%  40  2  0.0004  0.0286  2-Ethylhexanol  none  35%  65%  0%  40  2  0.0006  0.0290  Heptane  none  35%  65%  0%  40  3  n/a  2-Heptanone  none  35%  65%  0%  40  2  0.0003  0.0288  2-EHA  none  35%  65%  0%  40  2  0.0012  0.0260  Results for Continuous Back Extractions with Aqueous Formaldehyde  Recovery to  Formaldehyde  Extract Product  Recovery to  Glycolic  Raffinate Product  Ex.  H2SO4  Oligomers  Amine  Heptane  2-EHA  43  98.4%  100.0%  98.8%  100.0%  95.3%  44  99.8%  100.0%  99.0%  100.0%  100.0%  45  99.4%  100.0%  100.0%  100.0%  94.7%  46  98.8%  100.0%  98.0%  100.0%  94.4%  47  98.8%  100.0%  98.0%  100.0%  94.4%  48  98.7%  99.8%  100.0%  99.5%  Extraction of Sulfuric Acid from Aqueous Glycolic Acid› 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).  Example 49  Examples 43-48  Feed Conditions for Continuous Back  Extractions with Aqueous Formaldehyde  Solvent Flow  Solv. wt%  Ex.  TEHA  2-EHA  Heptane  g/min  (aq. HFr)  water  43  9.33%  36.5%  50.65%  16.5  49.00%  51%  44  7.38%  29.1%  60.89%  31.5  45.00%  55%  45  7.54%  26.3%  63.71 %  22.0  42.00%  58%  46  7.54%  26.3%  63.71 %  17.0  49.00%  51%  47  7.54%  26.3%  63.71 %  11.3  42.00%  58%  48  7.41%  27.7%  62.49%  11.3  49.90%  50.1% 