In alternative embodiments, provided are processes comprising the continuous isolation and purification of cannabinoids and further isomerization of the purified cannabidiol to ?8tetrahydrocannabinol ( ?8THC) and ?9tetrahydrocannabinol ( ?9THC). In alternative embodiments, provided are processes for converting ?8-THC into ?9-THC. In alternative embodiments, provided are processes for the industrial scale continuous isolation and purification of cannabinoids and further isomerization of the purified cannabidiol to delta ?9 -THC.