下面是一个claisen 酮酯缩合反应的具体操作过程，你参考下吧
NaH ( 0.225 mol ）was added to a dry flask under N2, then THF (200 mL) was added. The reaction mixture was cooled to 0  °C. During the cooling process, 酯( 0.150 mol) was added in one portion, then 酮 ( 0.15mol) was added dropwise over 30 minutes. The mixture was stirred at 0 °C for 1 h, allowed to warm to ambient temperature and was heated to 65 °C for 16 hours. The solvent was removed and diluted with water, and extracted to remove unreacted material. The aqueous phase was acidified with 1N HCl and extracted with DCM. The organic layer was washed with water, brine and dried to yield (11.2 g, 33%)，