The present invention provides a low pressure generating plasma reactor closed loop process, comprising: feeding a fresh feed gas flow and a fresh feed absorption liquid flow to a plasma reactor closed loop comprising a condenser, a liquid loop, a recycle gas loop, and a plasma generator; converting feed gas to reactive plasma products in the plasma generator; quenching and absorbing the reactive plasma products into an absorption liquid circulating in the liquid loop where the reactive plasma products react to form liquid reaction products, thereby generating low pressure in the closed loop; monitoring the composition and low pressure of the recycle gas loop and, if the pressure increases, adjusting the composition of the fresh feed gas flow and / or fresh feed absorption liquid flow to bring the composition of the feed gas towards stoichiometric ratio with the absorbed reactive plasma products; extracting circulating absorption liquid, containing the liquid reaction products, from the plasma reactor closed loop as a product flow. The present invention also provides a low pressure generating plasma reactor closed loop system, comprising a plasma generator, a condenser, a recycle gas loop, a liquid loop, and a pump.