Yesterday we took a look at some of the most important chemical structures you should know about in cosmetic chemistry. Today we'll take a look at halogen compounds, hydrocarbons, imidazolines, inorganic acids, isethionates, ketones, and phenol.
1. HALOGEN COMPOUNDS
Halogen compounds are molecules containing atoms from the Group 17 elements, such as fluorine, chlorine, bromine and iodine. They're not commonly used in cosmetics, although polytetrafluoroethylene (PTFE for short, or Teflon) is utilized as a bulking agent, slip modifier and binding agent in products like power products. It's useful for smoothing out the skin by filling in fine lines and wrinkles.
Figure 1. Polytetrafluoroethylene
2. HYDROCARBONS
Hydrocarbons are simply molecules which contain C's and H's. In cosmetics they are typically used as solvents like isododecane. Other common hydrocarbons comes in the form of mineral oil and petrolatum.
Figure 2. Isododecane
3. IMIDAZOLINE
A type of heterocyclic N structure containing a double bond. Imidazolines like cocoyl hydroxyethyl imidazoline are typically used for conditioning and anti-static agents in hair products.
Figure 3. Formation of an imidazoline structure
Figure 4. Cocoyl hydroxyethyl imidazoline
4. INORGANIC ACIDS
These are non-carbon molecules that can donate H+ ions to adjust pH. Aside from just adjusting pH, inorganic acids like phosphoric acid can be used to create buffer systems in a formulation whose stability depends on maintaining a certain pH range.
Figure 5. Phosphoric acid
5. ISETHIONATES
An organic molecule containing an OH group and a sulfonic acid two C's away. In organic chemistry when labeling the number of C atoms relative to another functional group, we label the first C as alpha, the second C as beta, etc. Thus in this case, sulfonic acid is beta to the OH group. These molecules are common surfactants in cleansing products like shampoos, such a sodium cocoyl isethionate.
Figure 6. General structure of isethionates
Figure 7. Sodium cocoyl isethionate
6. KETONES
A common functional group in chemistry defined by a C double-bonded to an O and single-bonded to an R-group. Simple ketones are mainly solvents (ex: methylisobutyl ketone) and fragrance materials in cosmetics, although ketones are common components of larger molecular structures in many cosmetic ingredients like carbohydrates.
Figure 8. General structure of a ketone
Figure 9. Methylisobutyl ketone
7. PHENOL
Benzene rings with an attached OH group. These molecules are usually used for anti-bacterial or anti-oxidant purposes. Some phenols are also direct hair dyes and flavors. Methylparaben is one of the most common examples of phenols used in cosmetics.
Figure 10. General structure of a phenyl ring
Figure 11. Methylparaben
All right, that's gonna do it for today. See you tomorrow!