Decarb Opinions

[cyclopath]

@borysses

The energy reguired for decarb is the same regardless of pressure

Exactly! MgO or other catalysts can change that energy requirement. Presumably an enzyme can be had as well

@Photon_noir

Catalysts can be used to your advantage for the decarboxylation reactions of cannabinoid acids, without affecting (or even hopefully increasing) the activation energy of undesired rxns. As long as your crude or solution thereof is totally devoid of water (anhydrous), I usually recommend dry magnesium oxide (MgO) as a decarboxylation catalyst, though other alkaline earth metal oxides and some transition metal oxides will also work, to varying degrees. Since decarboxylation is a pseudo-first-order rxn, the catalyst lowers the required temperature to achieve a given rate of decarboxylation. For example, based on my observation, just a teaspoon or less of MgO per liter of crude resin appears to let the THCa and other cannabinoid acids decarboxylate at a rate typically seen at about 280-300°F, at only 180°F.
MgO has the ancillary benefit of neutralizing acids present, even under the requisite anhydrous conditions, thereby effectively eliminating some or all of the plant acids present that could otherwise catalyze isomerization. However, that benefit uses the MgO as a reactant, not a catalyst, so if there is too much heat-ionizable acid present in your crude, it will “poison” (use up) your MgO decarboxylation catalyst.
I think you will find decarboxylation catalysis “essential” (heh) to retaining your terpenes, with or without inert gas pressure.
In any case using MgO, you should be forewarned that adding too much MgO to your crude will cause it to coalesce, turning the MgO into a blob of concrete at the bottom of your decarboxylation flask or beaker, even with stirring. So err on the side of caution and only add that maximum of 1 teaspoon per liter of crude!