thumb|right| a schematic representation of a soxhlet extractor 1: stirrer bar 2: still pot (the still pot should not be overfilled and the volume of solvent in the still pot should be 3 to 4 times the volume of the soxhlet chamber) 3: distillation path 4: thimble 5: solid 6: siphon top 7: siphon exit 8: expansion adapter 9: condenser 10: cooling water in 11: cooling water out thumb|right|animation describing mechanism of soxhlet extractor a soxhlet extractor is a piece of laboratory apparatus invented in 1879 by franz von soxhlet. it was originally designed for the extraction of a lipid from a solid material. however, a soxhlet extractor is not limited to the extraction of lipids. typically, a soxhlet extraction is only required where the desired compound has a limited solubility in a solvent, and the impurity is insoluble in that solvent. if the desired compound has a significant solubility in a solvent then a simple filtration can be used to separate the compound from the insoluble substance. thumb|left|fruit extraction in progress. the sample is placed in the thimble. normally a solid material containing some of the desired compound is placed inside a thimble made from thick filter paper, which is loaded into the main chamber of the soxhlet extractor. the extraction solvent to be used is taken into a distillation flask and the soxhlet extractor is now placed onto this flask. the soxhlet is then equipped with a condenser. the solvent is heated to reflux. the solvent vapour travels up a distillation arm, and floods into the chamber housing the thimble of solid. the condenser ensures that any solvent vapour cools, and drips back down into the chamber housing the solid material. the chamber containing the solid material is slowly filled with warm solvent. some of the desired compound will then dissolve in the warm solvent. when the soxhlet chamber is almost full, the chamber is automatically emptied by a siphon side arm, with the solvent running back down to the distillation flask. the thimble ensures that the rapid motion of the solvent does not transport any solid material to the still pot. this cycle may be allowed to repeat many times, over hours or d
Analytical_chemistry Distillation Laboratory_glassware Laboratory_techniques