Observed data of Orion KL, Sgr B2, and B1-b taken with different instruments (histogram black spectrum) together with the synthetic spectra obtained using the column densities given as upper limits in Table 2 (thin red curve). The synthetic total model for the 30 m data of Sgr B2(N) (see Belloche et al. 2013) and Orion KL (see Cernicharo et al. 2016) is overlaid in green. A v_LSR of +9.0 km s^-1, +64.0 km s^-1, and +6.7 km s^-1 is assumed for Orion KL, Sgr B2, and B1-b, respectively.