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The following examples illustrate the hydrocarboxylation of MDA in acetic acid catalyzed by various strongly acidic homogeneous catalysts. MDA was prepared as described above in Example 66. 

To a Hastelloy 276C 300 mL autoclave equipped with a liquid sampling loop and a high pressure addition funnel was added acetic acid (60.05 g, 1.0 mo!), water (9.0 g, 0.5 mo!), and trifluoromethanesulfonic acid catalyst (0.375 g, 2.5 mmol). The autoclave was heated with a heating block, with temperature control provided by feedback via a thermocouple 1 o in the autoclave thermowell. Pure carbon monoxide gas (>99.9%) was fed to the autoclave via a high pressure regu› lator. The MDA (66.26 g, 0.5 mo!) was added to the addition 15 funnel (blowcase). The autoclave was sealed, flushed with CO and heated to 140° C. under 100 psig carbon monoxide. The addition funnel containing the MDA was heated to 100° C. Upon reaching 140° C. in the autoclave, the MDA was charged to the autoclave by pressurizing the addition funnel. 20 Immediately upon completing the liquid addition, a sample was removed from the autoclave (time zero) and the pressure was adjusted to 1000 psig CO. The temperature and pressure were maintained using pure carbon monoxide for the duration of the 4 hour reaction. Samples were removed from the auto- 25 clave at 15 min, 30min, 45 min, 60min, 120min, 180minand 240 min. The samples were analyzed by GC and HPLC. Final conversion and selectivity is given in Table 14. 

Example 92 was repeated except the acid catalyst and amount were as given in Table 14. 2.5 mmol of acid catalyst was used in each case. The final MDA conversions and selec› tivities are given in Table 14. 

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The following examples illustrate the effect of feed water content, temperature, pressure, and catalyst level on the hydrocarboxylation of trioxane or paraformaldehyde with valeric acid and glycolic acid as solvents/reactants and triflic acid as catalyst. 

## Example 92 

## Examples 93-96 

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The continuous hydrocarboxylation was carried out using a reactor system containing Hastelloy 276C autoclave (125 ml nominal volume) and associated feed and product storage equipment. The high pressure autoclave was fitted with a hollow shaft Rushton turbine impeller (for gas introduction and dispersion), baffles, thermowell, 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 thermowell. 

Pure carbon monoxide gas (>99.9%) was fed to the auto› clave via a high pressure flow controller. The gas entered the body of the autoclave via groves in the impeller bearings. The off gas flow rate was monitored by a dry bubble-type flow meter. The flow rates of the two liquid feeds were controlled to a precision of 0.001 ml/min with double-barreled 500 ml high-precision syringe pumps connected to stirred feed ves› sels. 

Reactor effluent passed through heated Hastelloy tubing, an automatic pressure control valve (research control valve), and into a 1.0 L heatable Hastelloy collection vessel. The effluent collection vessel was fitted with a chilled coiled con› denser. The gas outlet from the effluent tank was connected to a manual back pressure regulator to maintain vessel pressure at 40-100 psig. Temperatures, pressures, and other relevant system parameters were recorded automatically by a distrib- uted control system. 

Feed 1 (0.4 g/min) and Feed 2 (0.39 g/min), having the composition given in Table 15 were fed to the reactor. Carbon monoxide was fed at a rate of998 SCCM as noted in Table 16. The reaction was run at a pressure of 1500 psig and a tem› perature ofl 70° C. with a residence time of85 minutes. Table 16 also gives feed molar ratios and the source of formalde› hyde. For Example 107 the source was trioxane. 

Samples of the hydrocarboxylationreaction were analyzed by HPLC. Conversion, space-time yield, and selectivity of reacted formaldehyde to end products are summarized in Table 17. Any glycolic acid fed was subtracted out for con› version and yield calculations. Methanol was present as free methanol, methyl glycolate, and methyl valerate, and was converted to free methanol, glycolic acid, and valeric acid by the analytical method. 

Example 97 was repeated with the liquid feeds given in Table 15, the carbon monoxide flow rate, source of formal- dehyde, feed molar ratios, pressure, temperature, residence time given in Table 16. Conversion, space-time yield, and selectivity of reacted formaldehyde to end products are sum› marized in Table 17. 

## Example 97 

## Examples 98-143 

