In the early 1930s long-chain alkyl aryl sulphonates with benzene as the aromatic nucleus, and the alkyl portion made from a  kerosene fraction, appeared on the market in the USA. Again, these were available as the sodium salts extended with sodium sulphate. Both the alcohol sulphates and the alkyl aryl sulphonates were sold as such as cleaning materials, but did not make any appreciable impression on the total market. At the end of the Second World War alkyl aryl sulphonates had almost completely swamped the sales of alcohol sulphates for the limited uses to which they were applied as general cleaning  materials, but the alcohol sulphates were making big inroads into the shampoo field.

An exception was Teepol, a secondary alcohol sulphate which remained popular for some years. In common, however, with other chemical developments during this century, progress was not in one direction only. The limiting factor is always the availability of raw materials in a particular country. Con-currently with the above developments, there were developed, both in Germany and the USA, the lgepon type of compounds of which lgepon-T, the sodium salt of oleyl tauride is an example, and in Germany the Mersolates, which are alkane sulphates. In the United Kingdom, Teepol, a secondary olefine sulphate from petrochemical sources, was manufactured in large quantities and is still being produced in England and western Europe to this day.

The term "synthetic detergent" is used throughout this article, for a material which cleans (or is used for cleaning), but in  this definition soap is not included. Even so, this is still a wide definition, because, of course, it can refer to the active ingredient, or the solid, liquid, paste or powder compounded from this active matter. However, this should not lead to confusion, as the industry itself as yet makes no distinction in terminology between the basic material and the ready-for-use product.

The first synthetic detergents which fall into our definition of the term seem to have been developed by the Germans in the First World War period to allow fats to be utilized for other purposes. These detergents were of the short-chain alkyl naphthalene sulphonate type, made by coupling propyl or butyl alcohols with naphthalene and subsequent sulphonation, and appeared under the general name of Nekal. These products proved to be only fair to moderately good detergents, but good  wetting agents and are still being produced in large quantities for use as textile auxiliaries.