First, you need to recognize what the Octane Number capability and the factors which dictate the number.Contrary to what you might think, High Octane Number fuel is much less risky than low octane fuel. Low octane gas is therefore greater hazardous (flammable) than excessive octane.
Next, understand the relevance of Octane variety of the fuel. A four stroke recipricating engine running on the spark ignition process, is designed so that the fuel/air mixture ignites at the ideal moment in the cycle (usually just Before Top Dead Centre - BTDC).However, because compressing a gasoline causes it to get hotter, and due to the fact hot gas can spontaneously ignite (that is the essential of the Diesel engine) the gasoline air combination can "pre-ignite" (i.e. ignite before the spark) and there may be a symptom known as "knocking".
Therefore, the first technique to enlarge the octane range is by mixing high octane fuels into the low octane fuel.
The second approach is via the use of components in the fuel. Organic lead compounds have been used in the past to decrease the likelihood of pre-ignition and as a result elevate the octane wide variety of the fuel. Organic lead has been confirmed to be toxic and is no longer used now. But there are different components which can raise the Octane Number.
The third, and probably most vital technique to raise the Octane Number of the fuel, is via "Cracking" the fuel in a way that the resulting cracked aspects naturally have a higher Octane Number.
In summary, the procedures of blending, isomerism, cracking, reforming, and by the additon of "additives" in the petroleum refining plants, can motive the ensuing gasoline to have the greater applicable high Octane Number.