Propylene glycol: what it is, origin and application to the world of vaping.
What is propylene glycol
Propylene glycol is an odorless and colorless substance that falls into the category of chemical compounds. Also called by the term a-propylene glycol, it has a sticky consistency and a slightly sweet taste. It can be mixed with other liquids, such as chloroform, acetone and water to have different uses. In fact, its characteristics make it a very versatile product and a fundamental ingredient for the composition of liquids for electronic cigarettes.
On an industrial level, the production of propylene glycol is based on the hydration process of pure propylene oxide. The reaction can take place in two ways: at high temperatures (200-220 ° C) in a non-catalyzed manner; at a temperature between 150 ° C and 180 ° C in a catalyzed manner. Thus small quantities of alkali, sulfuric acid or exchange resin are used.
In both circumstances, a mixture to be further purified is obtained based on propylene glycol, dipropylene glycol (1.5%) and propylene glycol (20%). Once the refining phase is over, propylene glycol is obtained with a minimum purity level of 99.5% and of BP, EP, JP, USP or industrial grade.
Finally, this liquid can originate from a by-product of biodiesel, glycerol.
What is propylene glycol used for
The information regarding propylene glycol underlines how this biodegradable liquid performs above all the function of vehicle for active substances of different types. In fact, studies and research have applied the specific characteristics of this liquid to the most diverse sectors.
The fact of being soluble in water, combined with the remarkable solvent and wetting properties, make it one of the main ingredients of numerous compounds.
First of all it is, together with other ingredients, a fundamental part of the liquids used in the electronic cigarette to originate the vapor (therefore as an excipient).
In addition to this use, propylene glycol is also used:
- for the production of cosmetics and products related to well-being (it is one of the most important ingredients for the formulation of essential oils for massages);
- as a vehicle for fragrances of perfumes and other beauty products;
- as a food additive (it is indicated with the initials E1520);
- as a support during the fermentation phase of wine and beer (it is the refrigerant agent used in the refrigeration tanks);
- in cooling systems as a coolant;
- as a humectant in tobacco products;
- in saline solutions and antiseptic lotions;
- together with gelatin and wax to form soap bubbles;
- as part of the formulation of numerous drugs as a solvent;
- as an ingredient or basic solution for the production of solvents, disinfectants, polyesters and defrosting liquids;
- during theatrical productions and firefighter training sessions by powering the smoke machines to create artificial fumes.
Function of propylene glycol in the electronic cigarette
The effects of vaping are less marked than the traditional action of smoking, precisely because of the principle underlying the functioning of the electronic cigarette.
In fact, the smoke does not originate from the combustion of tobacco, but from the evaporation of a specific liquid to be inhaled. The ingredients contained in the composition of the preparation are:
- vegetable glycerol;
- propylene glycol;
- purified water;
- aromas;
- nicotine (optional).
The resistance, powered by the rechargeable battery, supports the production of vapor by subjecting the liquid contained in the cartridges to a nebulization process. Once the optimum temperature is reached, the mixture is transformed into water vapor. It is precisely this element that gives the name both to smokers who prefer e-cig (vaping) and to the use of the atomizer (vaping).
The e-cig fluid can take different forms and have variable compositions according to personal tastes. In any case, propylene glycol is the main ingredient and is used to combine the other parts of the formulation with each other.
Amount of propylene glycol in the electronic cigarette
The ratio of propylene glycol to vegetable glycerol is 50 to 50.
This is an important factor to keep in mind because to give a particular aroma to a fluid it is possible to add an additive or some accessory flavoring, even if the choice is completely personal.
The function of the aroma is to make the vapor emitted by the electronic cigarette fragrant, so it is possible to add an amount equal to 5-10% of the mixture to the propylene base. Please note that depending on the systems adopted to vape, the smoker may decide to modify the composition to obtain better performance and a result more in line with his needs. Not only are experiments frequent to find the perfect formula, but the effects and sensations caused by vaping change significantly.
For example, the presence of a higher quantity of propylene glycol (60-65%) enriches the sensations perceived by the palate. Secondly, it helps to counteract dry mouth, one of the most significant negative aspects during vaping. If, on the other hand, the quantity of vegetable glycerin is increased compared to that of propylene glycol (respectively 60-65% and 40-35%), lung-type shooting techniques are improved. However, there is a risk that the fluid has a sweetish aftertaste. So it is often necessary to add the aromas to have a more pleasant taste on the palate.
The ease with which it is possible to adapt the methods of preparation of chemical fluids to your needs has contributed to the spread of the vape. In fact, the possibility of customizing liquids is one of the reasons why vapers prefer to prepare the fluids themselves to be inserted in the cartridges!
The lack of a specific and univocal formula opens the door to the possibility of innovating and experimenting at will. Many aficionados vary the percentages of ingredients used to prepare different samples and find the recipe that best suits them. The important thing is that the products used have the highest possible level of purity and are of quality.
Where is propylene glycol found
This chemical substance is easily available: in fact it can be found for sale at any pharmacy or on specialized e-commerce sites.
Large-capacity bottles can also be purchased in stores that supply raw materials for a food laboratory and industrial departments. The ease with which it can be purchased is linked to its need in very different areas of the market, from the cosmetic industry to the pharmaceutical one, from the production of lotions to refrigeration and veterinary treatments.
In particular, the retail trade of propylene glycol supports the use of this product to meet the needs of smokers who opt for the electronic cigarette. The functioning of the e-cig is based on liquids whose components are vegetable glycerin, propylene glycol and flavorings. Vaping fluids (with or without nicotine) are sold only in authorized stores and tobacconists, however often smokers decide to prepare the liquids themselves. This solution allows you to add flavors chosen personally, so as to have a customized product compared to the standard models on the market.
