Abstract: Methods for purifying an acetonitrile waste stream are provided. An exemplary method for purifying an acetonitrile waste stream includes generating an acetonitrile waste stream during oligonucleotide synthesis and fractionating the acetonitrile waste stream to produce a single overhead fraction. The method includes condensing the single overhead fraction to produce a condensed single overhead fraction and contacting the condensed single overhead fraction with an adsorbent material to produce an acetonitrile stream that comprises an amount of an impurity that is reduced relative to the acetonitrile waste stream.

Abstract: Methods for removing 1,3,5-trimethylhexahydro-1,3,5-triazine and N-methylenemethanamine from a N-methylimidazole and methods for making oligonucleotides using N-methylimidazole are provided. In one embodiment, a method for removing 1,3,5-trimethylhexahydro-1,3,5-triazine and N-methylenemethanamine from a feedstock containing N-methylimidazole includes contacting the feedstock with small or medium pore molecular sieves. The small or medium pore molecular sieves adsorb 1,3,5-trimethylhexahydro-1,3,5-triazine and N-methylenemethanamine from the feedstock. The method further includes separating the small or medium pore molecular sieves from the feedstock.

Abstract: Methods and systems for purifying an acetonitrile waste stream and methods for synthesizing an oligonucleotide using a purified acetonitrile waste stream are provided. An exemplary method for purifying an acetonitrile waste stream includes providing an acetonitrile waste stream and fractionating the acetonitrile waste stream to produce a single overhead fraction. The method includes condensing the single overhead fraction to produce a condensed single overhead fraction and contacting the condensed single overhead fraction with an adsorbent to produce an acetonitrile stream that comprises an amount of at least one impurity that is reduced relative to the acetonitrile waste stream.

Abstract: Methods for removing 1,3,5-trimethylhexahydro-1,3,5-triazine and N-methylenemethanamine from a N-methylimidazole and methods for making oligonucleotides using N-methylimidazole are provided. In one embodiment, a method for removing 1,3,5-trimethylhexahydro-1,3,5-triazine and N-methylenemethanamine from a feedstock containing N-methylimidazole includes contacting the feedstock with small or medium pore molecular sieves. The small or medium pore molecular sieves adsorb 1,3,5-trimethylhexahydro-1,3,5-triazine and N-methylenemethanamine from the feedstock. The method further includes separating the small or medium pore molecular sieves from the feedstock.