L. Xun et al., A CONVENIENT AND PRACTICAL METHOD FOR CONVERSION OF PRIMARY ALKYL CHLORIDES TO HIGHLY PURE BROMIDES (GREATER-THAN-OR-EQUAL-TO-99-PERCENT), Synthetic communications, 24(5), 1994, pp. 733-743
Repeated treatment (second after the aqueous work-up) of primary alkyl
chlorides with ten equivalents (each) of lithium bromide in 3-pentano
ne at 120-degrees-C for a total of five hours gave the corresponding b
romides in excellent yield (86-96%) and with high chemical purity (gre
ater-than-or-equal-to 99%).