CBD doesn’t have a clear set boiling point (as does THC, at ~157 °C). It’s more in the 160-180 °C range. At or around “boiling point” temperatures, these molecules are well on their way to thermal decomposition (as opposed to a “gaseous state” of the intact molecules) - thus yielding different, simpler, unrelated molecules.
Note that various sugars (as in flavorings) also decompose in the range of 160 °C (or so). Found an excellent list of boiling temps for THCs, CBDs, as well as certain common Terpenes and Flavinoids:
https://www.nwsci.com/customer/docs/SKUDocs/RMR/Technical%20Data_Extractions_03.28.18.pdf
In the case of CBD-A (having the natural, unoxidized carboxylic acid existing on the Number 2 carbon atom), boiling points are significantly higher (316-531 °C). The CBD-A (to be bio-active, regardless of route of administration) need to have been decarboxylated to CBD (using heat over time - see this related paper).
One thought is that perhaps you (might) want to try to limit coil/wick-interface temperatures to lower values ?
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From this (pretty good, as they go) web-page (which includes some vaporization temperature values):
Consuming CBD as an edible makes it vulnerable to the “first-pass” through the gut and liver, where the body breaks it down. This strips some of the beneficial properties of CBD away, leaving a lower concentration for your body to receive than what you consumed.
Source: https://www.cbdbreaker.com/faq/cbd-boiling-vaporizing-point-a-guide-to-safe-vaping/
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Regarding oral ingestion, as opposed to vapor inhalation. First-pass liver metabolism transforms CBDs as well as THC to a metabolite with a Hydroxyl group on Number 11 Carbon atom. Metabolism renders CBDs, THC to be different molecules - having much lower pharmacodynamic efficacy at CB1 receptors (for THC). On the other hand, busting apart molecules (vaping at/around “boiling” temperatures) seems to be an even weirder form of unintended (and unpredictable) results. These companies sure make an “arm and a leg” of profits on these CBD suspensions. Here in Washington State, legal CBD flower-buds are only around 10 cents per milligram CBD (a fraction of the per milligram CBD costs accompanying the liquid formulations).