Plant waxes are the protective cover between the plant cells and their environment, by which they regulate their water loss, and protect themselves from the environment.
When we speak of plant waxes, it is usually as if it were a single compound, but a deeper look reveals that it is a mixture of simple Alkanes, Alcohols, Aldehydes, and Fatty Acids, ranging from 20 carbon chains, to about 34.
To put them into perspective, the well known Carnauba (C30 H62 O) and Candelilla (C31 H64 O) plant waxes are C-30 and C-31 molecules respectively. About the same consistency as bees wax, and denser than (C16 H34 O) ear wax.
| WAXES | ||
| Wax | Alcohol | Fatty Acid |
| Carnauba | CH3(CH2)28CH2-OH | CH3(CH2)24COOH |
| Beeswax | CH3(CH2)28CH2-OH | CH3(CH2)14COOH |
| Spermacetic (ear wax) | CH3(CH2)14CH2-OH | CH3(CH2)14COOH |
I’ve not found an analysis of cannabis plant waxes, but looking at plant waxes in general, here is a breakdown of what is in the waxes from the leaves of the xxxx plant, giving perspective as to the mixture:
| % of Fraction in Plant Waxes from:http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00581.x/full | ||||
| Carbon | Alkanes | Alcohols | Aldehydes | Fatty Acids |
| 20 | – | – | – | 1 |
| 21 | – | – | – | tr |
| 22 | – | tr | – | 2 |
| 23 | – | tr | – | 1 |
| 24 | – | 1 | 2 | 7 |
| 25 | tr | tr | – | 2 |
| 26 | Tr | 3 | 3 | 5 |
| 27 | 5 | 1 | 4 | 4 |
| 28 | 3 | 13 | 24 | 19 |
| 29 | 47 | 4 | 8 | 8 |
| 30 | 4 | 33 | 31 | 31 |
| 31 | 38 | 4 | – | – |
| 32 | 2 | 28 | 28 | 21 |
| 33 | 2 | 3 | – | – |
| 34 | – | 7 | – | – |
| Total | 72 | 9 | 1 | 2 |
| Tr = Traces less than 0.5% undetectable |
Notice that it is no longer an issue of non polar plant waxes, as only the Alkane molecules are non polar.
Molecular weights also become an issue, when you are talking about processes like SCFE CO2, where molecular weights above about 400 g/mol are mostly insoluble.
Looking at C-30 Carnauba wax for instance as CH3(CH2)28CH2OH or simplified as C30H62O, it has a molecular weight of about 438.8127 g/mol. http://www.webqc.org/molecular-weight-of-CH3%28CH2%2928CH2OH.html
| Symbol | Element | Atomic Wt | Atoms | Total |
| C | Carbon | 12.0107 | 30 | 360.321 |
| H | Hydrogen | 1.00794 | 62 | 62.49228 |
| O | Oxygen | 15.9994 | 1 | 15.9994 |
| Molecular Weight | 438.81268 g/mol |
That suggests of course that those molecules smaller than about C-27 will have a molecular weight below 400 g/mol, so are readily extracted by SCFE CO2 as well.
Here are some interesting reads on plant waxes:
Biology of the plant cuticle:
Leaf cuticular waxes are arranged in chemically and mechanically distinct layers: evidence from Prunus laurocerasus L.
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00581.x/full