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We present 247-GHz molecular line observations of methanol (CH$_3$OH) towardsixteen massive star-forming regions, using the APEX telescope with an angularresolution of $25''$. The sample covers a range of evolutionary states,including warm molecular cores, hot molecular cores, and ultracompact HIIregions. The hot cores, all of which include UC HII regions, show richmolecular line spectra, although the strength of different species andtransitions varies from source to source. In contrast, the warm cores do notshow significant molecular line emission. Multiple methanol transitions aredetected toward nine of the hot cores; eight of these had enough transitions touse the rotation diagram method to estimate rotational temperatures and columndensities. The temperatures lie in the range 104$-$168 K and column densitiesfrom $3\times10^{16}$ to $7\times10^{18}$ cm$^{-2}$. Using the average methanolline parameters, we estimate virial masses, which fall in the range from 145 to720 M$_\odot$ and proved to be significantly higher than the measured gasmasses. We discuss possible scenarios to explain the chemical differencesbetween hot cores and warm molecular cores. One of the observed methanol lines,$4_{2}-5_{1}A^{+}$ at 247.228 GHz, is predicted to show class II maseremission, similar in intensity to previously reported $J_0-J_{-1}E$ masers at157 GHz. We did not find any clear evidence for maser emission among theobserved sources; however, a weak maser in this line may exist in G345.01+1.79.

APEX Millimeter Observations of Methanol Emission Toward High-Mass Star-Forming Cores