TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The additional fresh crude C4 feed is added at a second volumetric rate that is 1.1-2 times the first volumetric rate of removed cis-butene-2 rich bottoms stream. The removed cis-butene-2 rich bottoms stream: contains at least 70 wt.% cis-butene-2 based on the total weight of the bottom stream; and is mixed with a butadiene lean raffinate stream. The 1,3-butadiene concentrate containing cis-butene-2 stream is introduced into a central portion of the vertical height of the third tower or into the third tower at a level of above 40%, preferably 40-60% of the vertical height of the third tower. EXAMPLE - Feed stream comprised (based on the total weight of the stream) of 1,3-butadiene (36%), 1,2-butadiene (less than 1%), cis-butene-2 (5%) and trans-butene-2 (7%), with the remainder being made up of a combination of butene-1, isobutylene, and saturates was employed in the process at an incoming flow rate of 745 gallons per minute (gpm). The extractive distillation tower was operated using a conventional mixture of acetonitrile and water, a bottoms temperature of 245 degrees F and pressure of 80 psig, and an overhead temperature of 115 degrees F and pressure of 65 psig with an external reflux flow rate of 860 gpm and a solvent flow rate of 2850 gpm. 1,3-Butadiene concentration tower was operated at a bottom temperature of 280 degrees F at 70 psig, and an overhead temperature of 125 degrees F at 65 psig with an external reflux flow rate of 515 gpm. The finishing distillation tower was operated at a bottom temperature of 175 degrees F at 130 psig, and an overhead temperature of 130 degrees F at 80 psig with an external reflux flow rate of 2160 gpm and a steam was introduced at a level 50% of the vertical height of finishing distillation tower. When bottoms stream of finishing distillation tower was recycled, the recycling stream contained 1,3-butadiene (37%), 1,2-butadiene (9%), cis-butene-2 (44%), and trans-butene-2 (9%) with the remainder being made up of a combination of butene-1, isobutylene, and saturates. The recycling stream was recycled to a zone at the rate of 40 gpm. When bottoms stream of finishing distillation tower was removed by way of stream (A), i.e. removed from the overall 1,3-butadiene extraction process, stream (A) contained 1,3-butadiene (1.5%), 1,2-butadiene (16%), cis-butene-2 (75%), and trans-butene-2 (5%) with the remainder being made up of a combination of butene-1, isobutylene, and saturates. Stream (A) was removed from the overall 1,3-butadiene extraction process at the flow rate of 40 gpm. The volumetric amount of additional fresh feed that could be added to original feed for processing in extractive distillation tower was 55 gpm to give product stream containing 1,3-butadiene (99.6%), and less than 0.4% of butene-1, cis-butene-2, and trans-butene-2.