A bit of thermodynamics (theenergycollective)

Some reasons why industrial uses of CO2 will never play any significant role in reducing CO2 emissions.

• CO2 sits at the bottom of a "deep thermodynamic well", meaning it has very low chemical energy, and any chemical use that converts CO2 into something else will need energy inputs similar to that produced when CO2 was created in the first place.
• Any use of CO2 for commodities such as plastic will most only mean a temporary delay before the CO2 is again released into the atmosphere when the commodity eventually is disposed of and decomposes.

Relevant citation: "[...] it is important to note that CO2 consumption by chemical processes (approx. worldwide ~ 100 Mt/y) cannot impact global CO2 levels, nor are they a means to address climate change (UK CO2 emissions in 2008 from power stations exceeded 200 Mt/y).  However, they could be a means to add value to a portion of the CO2 from carbon sequestration and storage processes."  (emphasis mine). 

The article also mentions using CO2 for enhanced oil recovery, which is the single industrial use which:
- involves considerable quantities of CO2
- actually sequesters the CO2 underground