Potassium Dodecyl Sulfate
Time: 2012-09-07 15:50:02
Potassium Dodecyl Sulfate
Synonyms
Sulfuric acid,monododecyl ester, potassium salt (1:1);
Dodecyl potassium sulfate;
Sulfuric acid, monododecyl ester, potassium salt;
Potassium lauryl Sulfate;
Category
Anionic Surfactant
>> Sulfate
>> Chain Alcohol Sulfate
>> Alkanol Sulfate
>> Linear Alkanol Sulfate
Chemical Numbering System
CASRN: 4706-78-9
EINECS: 225-190-4
Molecular Formula & Molecular Weight
Molecular Formula: C12H25KO4S;C12H26O4S.K (SciFinder Hill Rules)
Molecular Weight: 304.49.
Structure
Properties
Appearance    (1), white to slightly yellow crystals, flakes, or powder; (2), liquid.
Odor    faint characteristic odor.
Solubility    soluble in water.Aqueous solution is colorless transparent to translucent, transparency influenced greatly by concentration and temperature. Generally, as the concentration increases, the opacity will increases; as the temperature decreases, the opacity will also increases.
Hygroscopicity    hygroscopic. Powdery potassium dodecyl sulfate cakes easily, but the cake strength is not high.
Physical - chemical properties
Flash point, °C
> 90
Stability    stable in alkali, weak acid and hard water; unstable in strong acid, hydrolyzed, reduced to alcohol.
Risk    Solid form: flammable material; irritation, moderate irritation to skin, eye, respiratory. Harmful products of combustion are CO, CO2 and so on. Contact with strong oxidants, can cause to burn.
GHS (Rev.6) label:  
Liquid form: irritation, moderate irritation to skin, eye.
GHS (Rev.6) label:
Animal toxicity    Reference [1]: The metabolic fate of potassium dodecyl sulphate was studied in rats. Studies have shown that: by intraperitoneal, oral and intravenous administration, the urine within 12h, has approx. 17% inorganic sulfate metabolites, meanwhile, there is an ester in metabolites: butyric acid 4-sulphate.
Ecology    may be hazardous to environment. Water body should be given special attention.
Biodegradability    biodegradable.
Characteristics    excellent foaming, cleansing, emulsifying, wetting, permeating, dispersing, solubilizing, antistatic abilities. Resistant to hard water.
Note    (1), Avoid using in children cleaning products, such as shower gels, shampoo, skin care products.
Synthesis
Currently, sulfated reaction through continuous reactor (such as: falling film reactor) is the most widely used method for preparing sulfates.
Generally, dodecyl alcohol and sulfur trioxide react through reactor, then potassium hydroxide neutralizes, finally obtain product.
US patent 8,921,588 (Process for preparing sulfates and/or sulfonates in a micro-reaction system) presents a synthetic process. Conditions: mole ratio of sulfur trioxide and alcohols or other raw materials: 1:1; temperature: 30-60°C; reactor: falling film reactor.
US patent 6,455,488 (Process of making alkyl sulfate granulates) describes the preparation of a particulate alkyl sulfate, but does not involve the synthesis process.
US patent US 6,331,645 (Process for preparing powdery alkyl sulfates) describes the preparation of a powdery alkyl sulfate, but does not involve the synthesis process.
Quality Standards & Test Methods
1. Physical and chemical indexes
Item
Physical and chemical indexes
Powder
Granule
Liquid
Actives, %, ≥
90
88
27-30
Soluble materials in petroleum ether, %, ≤
1.5-3.5
1.5-3.5
1.5
Inorganic salts (K2SO4+KCl), %, ≤
5.5
5.5
2.0
pH (25°C, 1% solution)
7.5-10.5
7.5-10.5
7.5-10.5
Whiteness (WG), ≥
75
/
/
Color (5% solution), Klett, ≤
/
30
30
Moisture, %, ≤
3.0
5.0
/
Density, g/mL, approx.
0.48
0.48
1.03
Test Methods
(1), Actives
GB/T 5173 Surface active agents and detergents-Determination of anionic-active matter by direct two-phase titration procedure
ISO 2271 Surface active agents -- Detergents -- Determination of anionic-active matter by manual or mechanical direct two-phase titration procedure
(2), Soluble materials in petroleum ether
GB/T 11989 Anionic surface active agents - Determination of soluble matter content in light petroleum
ISO 894 Surface active agents -- Technical sodium primary alkylsulphates -- Methods of analysis
(3), Inorganic salts
GB/T 15963 Sodium lauryl sulfate, potassium sulfate and potassium chloride calculated.
ISO 894 Surface active agents -- Technical sodium primary alkylsulphates -- Methods of analysis
(4), pH
GB/T 6368 Surface active agents - Determination of pH of aqueous solution - Potentiometric method
ISO 4316 Surface active agents -- Determination of pH of aqueous solutions -- Potentiometric method
(5), Whiteness (WG)
GB/T 13173 Surface active agents - Detergents - Testing methods
(6), Color (Klett)
GB/T 8447 Industrial linear alkylbenzene sulfonic acid, Appendix A
(7), Moisture
GB/T 13173 Surface active agents - Detergents - Testing methods
(8), Density
GB/T 4472 Determination of density and relative density for chemical products
ISO 758 Liquid chemical products for industrial use -- Determination of density at 20 degrees C
2. Hazardous substances indexes
Item
Hazardous substances indexes
Powder
Granule
Liquid
Heavy metals (as Pb), mg/Kg, ≤
20
20
20
As, mg/Kg, ≤
3
3
3
Test Methods
(1), Heavy metals (as Pb)
Safety and Technical Standards for Cosmetics (2015 Edition)
GB/T 30799 The test method of food detergents - Determination of heavy metals
(2), As
Safety and Technical Standards for Cosmetics (2015 Edition)
GB/T 30797 The test method of food detergents - Determination of total arsenic
3. Further explanation
(a), On physical and chemical indexes: firstly, shall be indicated carbon atom distribution; secondly, shall be indicated average molecular weight.
Major Uses
1. Personal care products
Cleansing agent, foaming agent, emulsifying agent in personal care products.
For example, main ingredient or auxiliary ingredient for cleansing agent, foaming agent in toothpaste, shampoo, hand sanitizer and other products.
(1a), Toothpaste
U.S. Patent 5,723,105 and US patent 5,599,526 describe a visually clear gel dentifrice.
(1b), Shampoo
U.S. Patent 5,145,607 describes an optically clear conditioning shampoo.
2. Household detergents
Main ingredient or auxiliary ingredient for cleansing agent, foaming agent in laundry detergent and other household products.
Particularly, suitable for the preparation of high bubble and light-duty detergents.
3. Industrial cleaning agents
Main ingredient or auxiliary ingredient for cleansing agent, foaming agent in car cleaning products, metal cleaning products and other industrial cleaning products.
Particularly, suitable for the preparation of high bubble detergents, for example, car cleaning agents.
4. Fire extinguishing agent
Use as foaming agent.
5. Water treatment
Foaming agent, floating agent in wastewater treatment.
For example, wastewater treatment commonly uses physical and chemical process (coagulating sedimentation or flotation) in printing and dyeing industry.
Physical and chemical process is a mature technology. The process operates simply and costs cheaply.
In the coagulating sedimentation or flotation process, aluminum coagulant is one of the most widely used coagulants; magnesium coagulant is widely concerned because of green safety.
Potassium dodecyl sulfate has good foaming property and water solubility. At the same time, potassium dodecyl sulfate has good stability in a wide pH range.
So potassium dodecyl sulfate is very suitable for use as floating agent in flotation process.
6. Emulsion polymerization
Emulsifier, particle size controlling agent in emulsion polymerization. For example, polyvinyl chloride emulsion polymerization.
7. Ore-dressing
Use as foaming agent, floating agent.
8. Textile, leather
Use as emulsifier, foaming agent, cleansing agent, wetting agent, antistatic agent, solubilizing agent.
9. Electroplating industry
Use as wetting agent (Anti-pinhole agent).
Can reduce or eliminate pinholes.
10. Paper Industry
Use as cooking penetrant, wastewater flocculant, deinking agent.
11. Pets
Main ingredient or auxiliary ingredient for cleansing agent, foaming agent in shampoos and other pet products.
Manufacturers
 
References
[1]: W. H. B. Denner. The Metabolism of Potassium Dodecyl [35S]Sulphate in the Rat. Biochem. J. (1969) 111, 43.
Update: 20131018(1); 20160723(2);