Ethanol methanol, comparison, supercritical

Figure 2. Comparison of ethyl and methyl alcohols as supercritical desulfurization fluids, for coals of varied organic sulfur/ pyritic sulfur ratio, (ethanol -------, methanol — —)...

Table II. Comparison of Product Distributions for Methanol and Ethanol as Supercritical Extractants, and Effect of Potassium Hydroxide...

The use of supercritical CO2 to extract AR from cereal material was only recently presented (49). Pure supercritical CO2 was not able to extract AR even at pressures as high as 35 MPa and SS C. This result was attributed to the amphiphilic character of the AR and the non polar character of the supercritical CO2. With the addition of 10% of ethanol or methanol, it was possible to obtain extracts even at near the critical pressure (8 MPa). The optimal pressure was determined to be 3SMPa at S5°C when ethanol or methanol acted as co-solvent. The co-solvent was added as 10%wAv of the CO2. The CO2 flow was kept constant at Sg/min during the experiments. A comparison of the supercritical CO2 extraction with die addition of ethanol and classical extraction methods was made. For the classical method, pure acetone extraction at O.IMPa and 20°C was used. Between 15 and 30 MPa at 55°C, 8 to 80%w/w higher yields of AR crude extracts for the extraction with supercritical CO2 with co-solvents were obtained than for pure acetone extraction (refer to figure 2). However, the HPLC analysis of the extracts showed similar composition (49). 

Figure 38 X-ray powder diffraction patterns of the PbS nanoparticles obtained via RESOLV with the rapid expansion of (top) supercritical ammonia/Pb(N03)2 solution and (bottom) supercritical methanol/Pb(N03)2 solution into ethanol/Na2S solution. The pattern for bulk PbS in the JCPDS database is also shown for comparison. (From Ref. 259.)... 

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