Also introduced the "oleum" system in which water was replaced by oil.

Then oleum is dissolved in water to produce more sulfuric acid.

The oleum is then diluted with water to form concentrated sulfuric acid.

An oil refinery is located at Oleum, hence the name from "petr".

Another way to make it is reacting oleum and hydrochloric acid with selenium.

Until this process was made obsolete by the contact process, oleum had to be obtained through indirect methods.

Iodine dissolves in oleum to make a bright blue solution of I and sulfur dioxide.

Certain compositions of oleum are solid at room temperature, and thus are safer to ship than when liquid.

Badger also produced acid and oleum which are necessary for the production of these forms of ammunition.

Sulfuric acid itself is regenerated by dilution of part of the oleum.

A stronger reagent, oleum, is needed to introduce the second nitro group onto the aromatic ring.

Sulfuric acid is usually prepared and shipped as the acid precursor oleum.

It is made by reacting sulfur trioxide with sulfuric acid to produce oleum.

The name is derived from the Latin word "oleum" due to the discovery of crude oil in nearby Ischua.

The sulfonation agent is oleum, a solution of sulfur trioxide in sulfuric acid.

For the community in California, see Oleum, California.

It can also be expressed as a percentage of sulfuric acid strength; for oleum concentrations, that would be over 100%.

One important use of oleum as a reagent is the secondary nitration of nitrobenzene.

Such compounds are prepared by treating CuPc with chlorine, bromine or oleum.

When dissolved in fuming sulfuric acid (65% oleum), iodine forms an intense blue solution.

In addition, oleum is less corrosive to metals than sulfuric acid, because there is no free water to attack the surfaces.

The crystoleum, from "crystal" + "oleum" (oil), process was yet another method of applying colour to albumen prints.

Solid oleum can then be converted into liquid at the destination through steam heating or dilution or concentration.

A second method for the synthesis involves the reaction of selenium with oleum and hydrochloric acid:

This has now mostly been replaced by the less expensive procedure that uses a nearly 1:1 solution of oleum and azeotropic nitric acid (70%).