if you are using a plant oil extract. like QWISO or ethanol or BHO or stuff or full soaked, sludgy acetone extract; the distillation at reduced pressure should give you your desired compounds. the terpenes though are a different case, as they are more volatile it seems and have low boiling points. also, the boiling points of CBD and THC and other cannabinoids (and molecules in general) are lower when the pressure is lower (i think it's called boyle's law, lol, no that's related but different but now you, i've got myself wanting to go bak and learn that)
if you have a bunch of oil and put it in a liter flask, 1000ml
or 500ml or 2L or 3L
you can distill in a glass on glass, ground glass joint setup, with a short path distillation unit and maybe a vacuum jaketed vigreux column (fractioning column, but with a vacuum around it, so the flask doesn't need to be super heated (which could decompose compounds maybe) also, the vacuum lowers the boiling point so the same principle, but also, because when a molecule is heated above a certain temperature, it may decompose before it boils, whereas, when the boiling point is depressed, the molecule can be distilled at a temperature that doesn't destroy it.
heating mantle, flask (n neck, where n is a positive real integer, hahahaha humor), short path distillation condenser, vacuum take off adapter, receiving flask. vacuum jacketed vigreux column if looking to get better fractions (fractional distillation
on a glass joint, the millimeters is the first number, like a 14mm is 14/X
the length is X, and the taper is 1/10 so it fits interchangeably.
there are many types used, custom and yada whatnot, but alot of common types to look for are below. in europe for example, 29/26 is used more than 29/42 like in the usa. but they are both inter changeable, a male 29/42 will enter a female 29/26, oh baby, and have 42-26mm, a 16mm overage into the flask. thermometer adapters are usually 10mm but are on a different piece like a 24/40 claisen adapter or short path distillation head. regardless of the depth, a 10/30 thermometer adapter will fit that.
i don't know much about terpene stuff yet, i just part know about it.
10/30 are usually thermometer ports
29/42 a little better than mid
large stuff is
most short path, distillation heads have a mini vigreux on them anyway, and the good ones are vacuum jacketed.
basically, imagine putting a garden hose over a tea kettle spout and looking for steam at the other side. in order to get the output to be steam, the hose walls need to keep at boiling temperature, and means it needs a vacuum surrounding like space or an environment at the same temperature, like the hose going through a pool of boiling water (but actually steam is higher than boiling, so depending on the length of the hose, it would actually cool the vapor which is hotter than boiling water).
a cow reciever (i think pig sometimes) is a type of "vacuum take off adapter" that has male joint outputs that resemble nipples basically, it is used to hold multiple, typically 3-4 flasks, which are rotated as the fractions change, in order to keep the system (well i want to say sealed or hermetic but it is technically not the word) together or whatnot, under vacuum, uninterrupted and all that.
essential oil distillation sets may be able to collect terpenes, if you have a flask and condenser already, getting a chromatography reservoir to hold the plant matter and a dean stark apparatus or moisture collecting/measuring piece would be it i think.
basically the bottom flask would be filled with water and boiled up through the chromatography reservoir that holds the plant matter. the steam and compounds would go through an arm (this piece you would need, a distillation adapter or arm or whatnot) trickle down a graham condenser (actually this would be a different piece than the short path distillation head / condenser for a number of reasons, one being that a graham condenser doesn't do well, except vertically) and into a dean stark apparatus, which has a valve that lets the hydrosol to be let out and the oil to be concentrated.
THIS IS THOSE PIECES IN ACTION FOR FRACTIONAL DISTILLATION
(THE TITLE READS SHORT PATH DISTILLATION BUT ACTUALLY, I DON'T THINK THAT IS SHORT PATH DISTILLATION, BUT IT IS FRACTIONAL DISTILLATION ANYWAY)
attached are a list of some condenser types and a true short path distillation head/condenser (and it's vacuum, jacketed. you can see where they pulled the vacuum tube off when they melted it after pulling a vacuum, on the side, pretty cool huh?) you can search ebay for "short path distillation vacuum" and even get whole setups. a few thousand dollars, i consider expensive but it's probably in people's general spending range, i have really no idea.
geronimo, look at this baby (i mean the pieice lol)