The calculated distance (air line) between Tadmur and Khān Shaykhūn is approximately 111 miles respectively 178 kilometers.
By car or train, the actual journey to Khān Shaykhūn is certainly longer, as only the direct route (as the crow flies) between Tadmur and Khān Shaykhūn has been calculated here.
Air line (approximately)
178 kilometers
96 nautical miles