One major variation of the Wittig reaction is the Wittig-Horner reaction. The Wittig-Horner reaction uses triethylphosphate P(OEt)3 instead of PPh3. The P(OEt)3 is more water soluble than PPh3 and is easier to remove from the product than PPh3 (either by extraction with water or recrystallization with a polar solvent). Explain why P(OEt)3 is more water soluble than PPh3.