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percent, based on the total weight of the wash solvent, of a wash diluent comprising hexane, heptane, decane, meth› ylcyclohexane, benzene, toluene, xylene, isoparaffinic mixed hydrocarbons having a boiling range between 90 and 325° C., or a combination thereof; and about Oto about 20 weight percent of a wash modifier comprising 2-ethyl› hexanoic acid, !auric acid, bis(2-ethylhexyl)hydrogen phosphate, 2-ethylhexanol, 2-ethylbutanol, n-hexanol, n-octanol, n-decanol, or a combination thereof, to form a washed aqueous raffinate phase and an organic wash extract phase, wherein the weight ratio of the wash solvent to the aqueous raffinate phase is about 0.1: 1 to about 1: 1; 

(F) separating the washed aqueous raffinate and organic wash extract phases; and 

( G) combining the organic wash extract phase with the extrac› tion solvent of step (B) or with the organic extract phase of step (C). 

Embodiment 32 is a process that includes the features of any one of embodiments 30 and 31, in which the acid catalyst comprises methanetrisulfonic acid. 

Embodiment 33 is a process that includes the features of any one of embodiments 30-32, in which the tertiary amine comprises tris(2-ethylhexyl)amine; the modifier comprises 2-ethylhexanoic acid; the diluent comprises hexane, heptane, decane, or a combination thereof; the wash solvent comprises hexane, heptane, decane, isoparaffinic mixed hydrocarbons having a boiling range between 90 and 325° C., or a combi› nation thereof; the wash modifier comprises 2-ethylhexanoic acid, n-hexanol, n-decanol, or a combination thereof; and the weight ratio of the modifier to the tertiary amine is about 2: 1 to about 4:1. 

Embodiment 34 is a process that includes the features of any one of embodiments 30-33, in which the aqueous form› aldehyde solution of step (D) comprises about 40 to about 55 weight percent formaldehyde and the aqueous formaldehyde extract of step (D) is passed to step (A). 

The principles laid out in the instant invention are further illustrated by the following examples. 

Glycolic acid solutions and extraction samples were ana› lyzed by liquid chromatography. Quantitation of analytes comprising glycolic acid, glycolate oligomers, and related species was performed using ion-exclusion chromatography after samples were subjected to acid hydrolysis in aqueous 25% v/v H$_{2}$ SO$_{4 }$ at 80° C. for 30 minutes. The analytes were separated on a Hamilton PRP X300 colunm using a 10 mM H$_{3}$PO$_{4 }$ mobile phase with a 1-20% v/v acetonitrile gradient. The eluting components were monitored using a UV detector set at 210 nm and their concentrations calculated based on calibration using external standards. Formaldehyde was determined by liquid chromatographic separation of the 2,4- dinitrophenylhydrazone derivative of formaldehyde and its subsequent detection by UV at 360 nm. The same acid hydrolysate from the procedure above was reacted with dini› trophenylhydrazine, then analyzed using a Phenomenex Luna CS colunm using a 1: 1 water:acetonitrile mobile phase under isocratic conditions. The formaldehyde concentration was calculated based on calibration using external standards. 

Reactor effluent and extraction samples also were analyzed for sulfur using a wavelength dispersive x-ray fluorescence (WDXRF) semi-quantitative application called UNI- QUANT™ (UQ). UQ affords standardless XRF analysis of samples. The data were mathematically corrected for matrix 

## EXAMPLES 

## General 

differences between calibration standards and samples as well as absorption and enhancement effects; i.e., inter-ele› ment effects. Instrument conditions for sulfur analysis were: Line, Ka; kV, 40; mA, 60; Filter, none; Collimator Spacing (mm), 150; Crystal, Ge III-C; Peak Angle (2q), 110.6712; Detector, flow; PHD Lower, 35; PHD Upper, 70; Collimator Mask (mm), 30; Peak time (s), 30. 

Extractor samples were diluted in isopropyl alcohol to minimize matrix effects and analyzed quantitatively using WDXRF. The WDXRF calibrations were performed using serial dilutions of stock standards prepared wt./wt. and certi› fied using ICP-OES. Instrument conditions for sulfur analysis were: Line, Ka; kV, 50; mA, 60; Filter, none; Collimator Spacing (mm), 700; Crystal, Graphite; Peak Angle (2q), 106.4608; --offset, 2.6696; Detector, flow; PHD Lower, 27; PHD Upper, 75; Collimator Mask (mm), 30; -Offset time (s), 10; Peak time (s), 50. 

For all extraction examples, the molar selectivity for the tertiary amine-containing phase (i.e., extraction solvent) for sulfuric acid (H$_{2}$ SO$_{4}$ ) over glycolic acid (GA) is defined as follows: 

Throughout the examples, the following abbreviations are used in the Tables: 

HFr=formaldehyde 

GA=glycolic acid and oligomers 

HOFr=formic acid 

DGA=diglycolic acid 

MAA=methoxyacetic acid 

TfOH=trifluoromethanesulfonic acid or triflic acid 

PFOA-H=perfluorooctanoic acid 

TEHA=tris(2-ethylhexyl)amine 

2-EHA=2-ethylhexanoic acid 

DEHPA=bis(2-ethylhexyl)hydrogen phosphate 

MTSA =methanetrisulfonic acid 

MDSA=methanedisulfonic acid 

MMSA=methylsulfonylmethanesulfonic acid 

BMMSA=bis(methylsulfonyl)methanesulfonic acid 

Preparation of Aqueous Glycolic Acid Solutions-Hydro› carboxylation reactor effluents were prepared for subsequent extraction experiments in the following manner for Examples 1-4: A mixture comprising formaldehyde, water, glycolic acid, and acid catalyst was fed continuously to a high pressure zirconium autoclave, nominally 125 mL volume, fitted with a hollow shaft Rushton turbine impeller (for gas introduction and dispersion), baffles, thermo well, gas inlet tube, and sip tube to maintain liquid level at approximately 90 mL and to provide an exit for product effluent. The autoclave was heated electrically by a band heater, with temperature control pro- vided by feedback via a K-type thermocouple in the autoclave thermo well. Pure carbon monoxide gas (>99 .9%) was fed to the autoclave via a Brooks flow controller. Reactor effluent passed through zirconium tubing, maintained at 60° C., an automatic pressure control valve, and into a Hastelloy collec› tion vessel (I liter), also maintained at 60° C. The collection vessel was drained every six hours and analyzed by liquid chromatography, gas chromatography, and X-ray sulfur 

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## Examples 1-4 

