a1. 100L of anhydrous ethanol was added to a pre-dried 300L reactor, cooled down to -5 to -10C by passing ice brine, and 13L of dichlorosulfoxide was added dropwise.
b1. 21.5kg of Arg.HCl of D-type was added, ice brine was turned off, and the reaction was naturally warmed up to room temperature for 24 hours.
c1. Warmed up to 35C reaction, TLC spot plate to follow the reaction, reaction ended about 48h.
d1.Concentration: at the end of the reaction, concentrated under reduced pressure to obtain L-arginine methyl ester dihydrochloride intermediate in oil form.
