The Lanphos range of phosphate esters is a versatile class of surfactants, possessing many of the surfactant properties useful in the formulation of Industrial and Institutional cleaners than other anionic surfactants, including:
Detergency
Foaming
Emulsification
Dispersing
Wetting
Solubilising
In addition to these, the Lanphos phosphate esters also possess properties not as commonly found in other classes of anionic surfactant, which include:
Defoaming
Hydrotropiicity
High electrolyte tolerance
Lubricity
Corrosion inhibition
Because of the unique chemical structure of phosphate esters, it is possible to design multifunctional surfactants with the required balance of the above properties to give optimum performance in a wide range of applications in the formulation of Industrial and Institutional Cleaners.
The following is a brief introduction to the parameters which you can change in the manufacturing process and chemical composition of phosphate esters that gives rise to these properties. CHEMISTRY You can produce Lanphos phosphate ester by reacting a hydroxyl containing molecule, typically an ethoxylated nonionic surfactant, with a phosphorylating agent. There are two main phosphorylating agents used in the preparation of phosphate esters:
a) Phosphorus pentoxide b) Polyphosphoric acid (TPA)
Phosphorus pentoxide phosphorylation conforms to the following general reaction: P2O5 + 3ROH ------> (RO) 2PO3H + (RO)2PO3H2
Diester Monoester
This reaction, if carried out at a 3:1 mole ratio (as above), gives equimolar amounts of monoester and diester phosphates, which relates to a ratio of approximately 65:35 on a weight/weight basis. However, by manipulating the reaction mole ratio and conditions, it is possible to achieve any ratio down to 20:80 (weight/weight). This reaction route also produces phosphoric acid as a by-product, however, the level is usually low, at below 1%.
Polyphosphoric acid is a complex mixture of orthophosphoric acid with pyro, tri, tetra, penta, and higher phosphoric acids. However, the grade commercially used has an average of four phosphoric acid groups and is sometimes referred to as tetra phosphoric acid (TPA). If for simplicity, we assume that the reaction is with tetra phosphoric acid, it follows the general reaction: HO-(PO3H)4-H + 3ROH -----> ROPO3H2 + H3PO4 Monoester This reaction produces predominately, monoester phosphate. If carried out at a mole ratio of 3:1, as above, results in a mole of free phosphoric acid forming, this typically relates to 5-10% on a weight/weight basis. With TPA phosphate esters, you can adjust the mole ratio; however, in this case, it only has the effect of changing the free nonionic content
Affect of Phosphorylating Route These two phosphorylating agents give products with entirely different compositions. The following table provides typical compositions (in % weight/weight) of products made by these routes.
| Phosphorus pentoxide | Polyphosphoric acid |
Monoester % | 30 - 75% | 80 - 90% |
Diester % | 60 - 20% | 2% |
Phosphoric acid % | 0.50% | 5 - 10% |
Free nonionic % | 5 - 15% | 1 - 10% |
The choice of phosphorylating agent is essential as the monoester and diester phosphate esters have differing properties. The following table lists the typical differences:
| Monoester | Diester |
Hydrotropicity | Excellent | Poor |
Electrolyte tolerance | Excellent | Poor |
Detergency | Fair | Good |
Wetting | Fair | Excellent |
Emulsification | Excellent (emulsion polymer) | Excellent (oils) |
Foaming | Higher | Lower |
Dispersing | Fair | Excellent |
The choice of hydrophobe has as significant an effect on the performance of phosphate esters as does the synthesis route. As previously stated, you can base phosphate esters on ethoxylated nonionic surfactants; however, there are some applications where unethoxylated products are used, such as fatty alcohols. The following table lists some of the properties that you can obtain with the various hydrophobes available:
Hydrophobe | Properties |
Fatty alcohol's (C8 - C18) | Very low foaming/defoaming |
Fatty alcohol ethoxylates | |
(C8 - C10) | Excellent wetting, good detergency low(ish) foaming |
(C10 - C14) | Fair wetting, good detergency, high(ish) foaming, good emulsification (emulsion polymer) |
(C14 - C18) | Poor wetting, poor detergency, excellent lubricity, good emulsification (oil) |
Aromatic & polyaromatic ethoxylates | |
Phenol | Excellent hydrotropicity, good lubricant additive |
Polyaromatic | Excellent dispersing |
In addition to the chemical nature of the hydrophobe, the degree of ethoxylation also greatly effects the performance of phosphate esters. The following table lists some of the general trends observed when changing the level of ethylene oxide:
Ethylene oxide content | Properties |
1 - 5 moles ethylene oxide | Good wetting, good emulsification (oils) |
5 - 15 moles ethylene oxide | Good emulsification (emulsion polymer), good dispersing, high electrolyte tolerance |
The Lanphos range of phosphate esters is specially developed optimising the above parameters to give exceptional performance in a wide range of applications using the expertise gained over many years of product development. Lankem is open to developing products that meet specific customer needs.
Lanphos phosphate ester recommended for Industrial and Institutional Cleaners
Electrolyte Tolerant Detergents - Phosphate esters can commonly find use in the formulation of highly built detergents. The high electrolyte solubility of these products allows detergents containing high levels of builders, such as caustic soda, silicates and sequestrants, to be formulated without the need for a hydrotrope. Products for this application include:
Lanphos PE245
Lanphos PE36
Hydrotropes - Phosphate esters based hydrotrope are amongst the most effective products, allowing the formulation of product containing up to 30% caustic soda.
The following products are in our current range: