Alkylating agents for quaternary ammonium compounds

A method of forming an alkylating agent for quaternary ammonium compounds, the method comprising reacting (i) an amine or polyamine having a primary or secondary nitrogen with (ii) a dialkyl oxalate in the presence of a solvent to form a reaction product including a majority of an amide ester compound having a structure of Formula I and minority of a diamide compound having a structure of Formula II:

• wherein
• R1 of Formula I and/or or Formula II is, independently, hydrogen, or selected from a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group;
• R2 of Formula I and/or Formula II is, independently, selected from a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group;
• and
• R′ of Formula I is a C1 to C20 alkyl group;
• and
• wherein the reaction product includes greater than 90 mole percent of the amide ester compound of Formula I and less than 10 mole percent of the diamide compound of Formula II.

A method of preparing a quaternary ammonium salt, the method comprising quaternizing a compound having a tertiary nitrogen with an alkylating agent, wherein the alkylating agent includes an amide ester compound having a structure of Formula I

• wherein
• R1 of Formula I is hydrogen, or selected from a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group;
• R2 of Formula I is selected from a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group;
• and
• R′ of Formula I is a C1 to C20 alkyl group.