Last Update: August 30, 2012
A 50-mL one-neck round-bottom flask was charged with 2.0 g of 325 mesh tin powder, 4.0 mL of H2O and 6.0 mL of benzyl chloride. The reaction mixture was heated to reflux being careful that the refluxing water heats the ground glass joint significantly above room temperature (note: solids often collect on the side of the flask; do not attempt to wash them back down into the solution). After 3 hours at reflux, the heat source was removed and the now two-phase reaction mixture was cooled in an ice bath. Upon ice cooling the lower phase solidified into a white mass. The liquid was discarded and the solid extracted by the addition of 10 mL of acetone. The extract was suction-filtered and the solid that remained on the filter was extracted with another 10 mL portion of acetone and filtered as before. The solvent was stripped using a rotary evaporator leaving a wet-looking white solid. The product was recrystallized from ethyl acetate (~8 mL) and the white product was recovered by vacuum filtration. Additional product could be obtained by concentrating the filtrate and cooling it on ice.
Present clean 1H and 13C NMR spectra to the instructor to obtain the elemental analysis and mass spectrum of this compound. Use the NMR spectra, elemental analysis and the mass spectral data to identify the compound. Tin has NMR-active isotopes and these can couple to protons (and less commonly, carbon). Is this coupling observed (as small satellite peaks around the main peaks in the 1H NMR spectrum), if so, what is JSn-H?