I always do The Steglich esterification with acid, alcohol, and DCC / DMAP. The reaction is always slow in my case, About a week. A determinant of whether the reaction proceeds is due to the formation of the precipitate by-product of DCC.

I see this example of synthesis if you are working with this condition Dawid Janasik

189 g (2 mol) of molten chloroacetic acid [94.5] were weighed into a laboratory autoclave lined with a PTFE sleeve and equipped with a PTFE-coated, magnet-driven multi-blade stirrer. By inserting the autoclave into a The autoclave was cooled in an ice / sodium chloride bath and the chloroacetic acid was frozen. At the same time, about 112 g (1.98 mol) of isobutene [57.1] were condensed into a receiver cooled by a dry ice / acetone cooling bath and transferred to the precooled autoclave, with part of the isobutene evaporating. The autoclave was closed and heated to 90 ° C, with an internal pressure of initially 10 bar. The reaction was continued at 90 ° C. for 6 hours with vigorous stirring. After cooling to room temperature, 277.4 g of product solution were removed from the autoclave and transferred to a rotary evaporator. It was distilled under a pressure of 50 mbar and the bath temperature was gradually increased to 90 ° C.

http://www.orgsyn.org/demo.aspx?prep=CV3P0141