An extensive search for the complex molecule trans-ethyl methyl ether towards several hot core regions has been performed .
Using the IRAM 30m telescope and the SEST 15m we looked at several frequencies where trans-ethyl methyl ether has strong transitions , as well as lines which are particularly sensitive to the physical conditions in which the molecule can be found .
We included G34.26 , NGC6334 ( I ) , Orion KL , and W51e2 which have previously been proven to have a rich chemistry of complex molecules .
Our observations can not confirm the tentative Orion KL detection made by [ Charnley et al .
( 2001 ) ] within their stated column density limits , but we confirm the existence of the trans-ethyl methyl ether towards W51e2 with a column density of 2 \times 10 ^ { 14 } cm ^ { -2 } .
The dimethyl ether/methanol ratio of 0.6 as well as the newly found ethyl methyl ether/ethanol ratio of 0.13 indicate relative high abundances of ethers toward W51e2 .
Furthermore , the observation of ethyl methyl ether also confirms the importance of ethanol as a grain mantle constituent .
We present new upper limits of around 8 \times 10 ^ { 13 } cm ^ { -2 } for the column densities of the molecule toward Orion KL , G34.26 , NGC6334 ( I ) and estimate the column density towards SgrB2 ( N ) to be of the same order .
The W51e2 observations are discussed in more detail .