Published online by Cambridge University Press: 25 May 2016
We discuss recent high-sensitivity observations carried out with the IRAM instruments of the shock chemistry associated with bipolar outflows. We highlight the recent mm-wave studies of L1157, a highly-collimated outflow driven by a Class 0 source. These observations illustrate nicely the chemical segregation produced by the outflow. Different molecular lines are observed to trace different components of the gas. Some molecules are abundant in the quiescent medium but are not observed in the shock (e.g. C3H2, N2H+, H13CO+, DCO+), whereas some other molecules are very enhanced at the shocked region (e.g. SiO, CH3OH, H2CO, HCN, CN, SO, SO2, H2CS). We briefly discuss the chemistry of the most important molecules, devoting special attention to the species which are thought to be abundant in interstellar ice mantles.