P - methoxybenzeneacetonitrile was prepared in 34.8 % yield starting from anisole, via chloromethylation, cyanogenation and fractional distillation.以苯甲醚为原料,经过氯甲基化, 氰化反应后, 通过精馏获得对甲氧基苯乙腈,总收率为34.8%....
His income approximated 8000 dollars a year.他的年收入近8000美元.His income approximated ten thousand dollars a year.他的年收入近万美元.The newspaper reports of the discussion only roughly approximated to what was actually said.报纸上只是粗略地报...
Its are orderly: The head - cervical - two upper limbs - pectoral abdomen - back - two ham - two crus.其顺序为: 头部 - 颈部 - 两上肢 - 胸腹 - 背 - 两大腿 - 两小腿.How does crus open sexual fracture to accompany massive haemorrhage to do?小腿开...
当脱硫剂累计饱和硫容达20%时,可用于生产硫酸.It was useful forH 2 SO 4 production when the accumulative saturationS capacity reached 20 %.目前使用氧化钙复合的镁基脱硫剂较为合理.It is rational to use complex desulphurization agent for pretreating hot metal.用途: ...