Description
Very similar to the alcohol ether sulfates but have been produced by two different routes:
- reaction with sulfamic acid gives the ammonium salt and the product contains equimolar quantities of ammonium sulfate.
- reaction with sulfur trioxide and neutralization with sodium hydroxide gives the sodium salt; the products are relatively free from inorganics.
The products based on nonyl phenol + 4-9 EO and, using sulfamic acid, were at one time common in washing up liquids but are now too expensive.
However, products made from nonyl phenol + 4-15 EO sulfated with sulfur trioxide, do find specialty uses. The products with high amounts of EO contain high quantities of 1,4-dioxane after sulphation, which is normally stripped off before sale.
Typical impurities are ammonium chloride (from sulfamic acid made material); l,4-dioxane (from high ethylene oxide raw materials and sulfur trioxide sulphation).
General properties:
Similar to ether sulfates, special properties are possible due to ring sulfonation as well as sulphation of the hydroxyl group.
Disadvantages
Doubts on biodegradability of the alkyl phenol residue. The ammonium salt (made via sulfamic acid) gives off ammonia in alkaline solutions and therefore restricts their use in detergents.
Applications
Household products
The largest use of sulfated nonyl phenol ethoxylates (4EO) made with sulfamic acid was in blends with LABS for use in hand dishwashing liquids where they gave high foam, low skin irritation, and low cost; they have now been superseded by the more cost-effective LABS/AES formulations.
Emulsion polymerization.
Agricultural emulsifiers.
Specification
|
Active matter |
30-40% |
|
Unsulfated |
1-5% (can be high if the manufacturer wishes to avoid ring sulfonation) |
|
Inorganic sulfate |
< 1 for sulfur trioxide production, 6-8% for ammonium salt made from sulfamic acid |
|
1,4-dioxane |
should be below 500 ppm for stripped material |
