Sodium Dodecyl Sulfate
Synonyms
SDS;
SLS;
Sodium Lauryl Sulfate;
Lauryl Sulfuric Acid Sodium Salt;
Lauryl Sulfate Sodium Salt;
Lauryl Sodium Sulfate;
Lauryl Sulfate Sodium;
Lauryl Sulfate Na-Salt;
Dodecyl Sulfuric Acid Sodium Salt;
Dodecyl Sulfate Sodium;
Sulfuric acid, monododecyl ester, sodium salt;
Sodium n-dodecyl sulfate;
K12;
Category
Anionic Surfactant
> Sulfate
>> Chain Alcohol Sulfate
>>> Alkanol Sulfate
>>>> Linear Alkanol Sulfate
Chemical Numbering System
CAS: 151-21-3
EINECS: 205-788-1
Molecular Formula & Molecular Weight
Molecular Formula: C12H25NaO4S；C12H26O4S.Na
Molecular Weight: 288.38
Structure
Properties
Appearance (1), white to slightly yellow crystals, flakes, or powder; (2), liquid (Solution).
Odor faint characteristic odor.
Solubility soluble in water, solubility in water is less than sodium laureth sulfate. 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 SDS cakes easily, but the cake strength is not high.
Physical - chemical properties
|
Water solubility, g/L |
100 (Not specified temperature)[1] 196 (20°C)[2] |
|
Density, g/cm3 |
> 1.11 (20°C)[2] |
|
Melting point, °C |
205.5[4] 193 - 207[2] |
|
Surface tension, mN/m |
42.6 (20°C, 0.1%)[2] 55.9 (20°C, 100mg/L)[2] 39.5 (25°C, CMC)[3] |
|
Log Kow (octanol - water) |
1.6[1,2] |
|
HLB |
40 |
|
Flash point, °C |
> 93 |
|
CMC, mmol/L, 25°C |
8.0 - 8.4[2] |
|
Krafft point, °C |
16 / 17[2] |
Stability stable in alkali, weak acid and hard water; unstable in strong acid, hydrolyzed, reduced to alcohol. Under acidic condition, hydrolytic stability is less than sodium dodecyl sulfonate, similar to sodium laureth sulfate.
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 label: 
Liquid form: irritation, moderate irritation to skin, eye.
GHS label:
Irritation of sodium dodecyl sulfate is higher than sodium laureth sulfate, lower than sodium dodecylbenzene sulfonate.
Animal Toxicity
Table 1 Animal toxicity values
|
rat oral LD50 |
1288mg/kg[4] |
|
rat intraperitoneal LD50 |
210mg/kg[4] |
|
rat intravenous LD50 |
118mg/kg[4] |
|
mouse intraperitoneal LD50 |
250mg/kg[4] |
|
rabbit skin LD50 |
10mg/kg[4] |
|
mouse intravenous LD50 |
118mg/kg[4] |
|
rat inhalation LC50 |
> 3900mg/m3/1h[4] |
Reproduction: reproductive effect[4]; oral studies, no adverse effects[2].
Ecology may be hazardous to environment. Water body should be given special attention.
Reference[6]: goldfish absorb sodium dodecyl sulfate from solution principally through the gills, and that sodium dodecyl sulfate is rapidly distributed throughout the body tissues, the highest concentration being found in the gall bladder. Sodium dodecyl sulfate was metabolised by the fish to butyric acid-4-sulphate, and was excreted by the kidney. Over a 24h period 68% and 38% of a prescribled dose was excreted from freely fed and unfed fish, respectively.
Reference[7]: in sodium dodecyl sulfate solution, Artemia Parthenogenetica LC50: 13.9 mg/L/96h, lower toxicity; Moina Mongolica Daday LC50: 3.5 mg/L/72h, moderate toxicity.
HSDB[1], also review more ecotoxicity values, for example: Americamysis Bahia (Opossum Shrimp) EC50: conditions: saltwater, static, 20°C, pH 7.5-8.0, dissolved oxygen 70-121% saturated; concentration: 16.5mg/L/96h.
Biodegradability biodegradable.
Reference[8]: degradation of sodium dodecyl sulfate in natural water body depends on the microorganisms, the optimum conditions: pH 6.5-9.4, about 36°C.
Characteristics excellent foaming, cleansing, emulsifying, wetting, permeating, dispersing, solubilizing abilities. The most commonly used alkyl sulfates. The most typical use is foaming agent. Resistant to hard water.
Note (1), Avoid using in children cleaning products, such as shower gels, shampoo, skin care products.
(2), In toothpastes, because unesterified dodecanol can bring bitter taste, recommend to choose sodium lauryl sulfate that content of not sulfated products is as low as possible.
(3), In hard water, there is a possibility that sodium lauryl sulfate solution is transparent in a concentration range, then transforms translucent state. At the same time, when concentration of sodium lauryl sulfate is higher than or lower than this concentration, the solution is transparent. The reason for this state may be related to water hardness, ionic strength, and so on.
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 sodium 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 (Na2SO4+NaCl), %, ≤ |
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
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, Product standards
(1), Chinese standards
(1a), GB/T 15963 Sodium lauryl sulfate
(1b), QB/T 2900 Oral care and cleansing products Sodium lauryl sulfate for toothpaste
(1c), Chinese Pharmacopoeia (2015 Edition) Sodium lauryl sulfate
4, Further explanation
(a), On physical and chemical indexes: firstly, shall be indicated carbon atom distribution; secondly, shall be indicated average molecular weight.
(b), Used in toothpastes or other cosmetics, should be test for harmful substances; or furtherly test for microorganisms.
(c), Used in medicine, must comply with pharmacopoeia execution.
Major Uses
1, Typical applications
Use as foaming agent.
Use as cleansing agent.
Use as emulsifying agent, dispersing agent.
Use as wetting agent.
2, Personal care products
Cleansing agent, foaming agent, emulsifying agent, denaturant in personal care products.
For example, main ingredient or auxiliary ingredient for cleansing agent, foaming agent in toothpaste, shampoo, hand sanitizer and other products.
Sodium lauryl sulfate is not recommended as the primary surfactant because of irritant. When sodium lauryl sulfate used as a co-surfactant, usage should not be higher than 10%[9] (by mass).
The products that contact with the skin for a long time, not recommended to use sodium lauryl sulfate
(1), Toothpaste
(1a), Fluorine-containing transparent toothpaste
Formula:
Sorbitol (70% solution) 60 (wt, the same below.)
Fumed silica 23
Glycerin 4.2
Sodium saccharin 0.2
Sodium lauryl sulfate 1.8
Titanium Dioxide 0.2
Methyl paraben 0.1
Sodium carboxymethyl cellulose 0.8
Sodium monofluorophosphate 0.76
Colourant appropriate amount
Flavor (essential oil) 1.5
Deionized water 7.44
Process: sodium carboxymethyl cellulose disperses in glycerin, add water and sorbitol (70% solution), swell; mix with other ingredients, grind, homogenize, fill.
(1b), Fluorine-containing opaque toothpaste
Formula:
Calcium hydrogen phosphate 45
Glycerin 14
Sodium saccharin 0.2
Sodium lauryl sulfate 1.8
Sorbitol 4
Methyl paraben 0.1
Sodium carboxymethyl cellulose 0.8
Titanium Dioxide 0.2
Sodium monofluorophosphate 0.76
Colourant appropriate amount
Flavor (essential oil) 1.5
Deionized water 31.64
Process: sodium carboxymethyl cellulose disperses in glycerin, add water, swell; mix with other ingredients, grind, homogenize, fill.
(1c), Anti-calculus, anti-plaque toothpaste (US 7,192,571)
Formula:
Hydrated alumina 30
Sorbitol (70% solution) 30
Xylitol 1
Calcium carbonate 5
Sodium lauryl sulfate 2
Xanthan gum 0.2
Calcium pyrophosphate 5
Network-based concentrated phosphoric acid 5
Carrageenan 0.5
Sodium Fluoride 0.11
Sodium monofluorophosphate 0.38
Flavor 1
Sodium saccharin 0.1
Deionized water 19.71
Process: xanthan gum and carrageenan disperse in glycerin, add water and sorbitol (70% solution), swell; mix with other ingredients, grind, homogenize, fill.
(1d), Whitening toothpaste (US 6,759,030)
Formula:
Methyl Methacrylate Crosspolymer GMX-0610 53.71
Hydroxyethyl cellulose 0.73
Carbopol 934 0.37
Hydrogen peroxide 10.00
Sodium Fluoride 0.38
Sodium lauryl sulfate 1.83
Flavor 1.00
Propylene glycol 8.75
Glycerin 6.84
Sodium Saccharin 0.17
Sodium benzoate 0.20
Benzoic acid 0.02
Sodium EDTA 0.05
Sodium hydroxide (10%) 0.20 pH 6.5
Deionized water 15.75
(2). Shampoo
(2a), Shampoo containing a gel network (US 8,653,014)
Sodium dodecyl sulfate 7.64
Sodium laureth-1 sulfate 3.55
Polyoxyethylene lauryl ether sulfate, sodium salt (EO> 1) 3.81
Cocamidopropyl betaine 1.50
Cocamide MEA 0.50
Stearyl alcohol 0.64
Cetyl alcohol 0.36
Dimethicone 330M 0.20
Ethylene glycol distearate 1.47
Polyquaternium-76 0.10
Sodium benzoate 0.25
Deionized water 79.98
* * * * * *
More, there is a solid hair cleansing, conditioning products, for example, US patent 7,670,998 Solid hair conditioning product.
(3), Hair dye
Used in hair dyes.
For example, US patent 7,883,550 Oleic acid free hair dye.
3, 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.
(1), Carpet detergent (US 5,580,495)
Sodium lauryl sulfate 7.5
Sodium pyrophosphate, sodium silicate and sodium sulfate 5.4
Polyoxyethylene fatty amine 0.5
Isopropanol 0.6
Butyl cellosolve 0.4
Limonene (fragrance) 0.007
Water 85.593
4, 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.
U.S. Patent 7,552,737 (Waterless car wash liquid composition and method for producing the same) describes a waterless car cleaning product.
5, Medicine
Pharmaceutical excipients. Use as emulsifier, wetting agent, water-soluble lubricant.
As a lubricant, lubricating effect is lower than stearic acid metal salt, however, sodium lauryl sulfate is a soluble lubricant, it can promote disintegration and drug dissolution rate.
With the compounding of stearic acid salts (such as: magnesium stearate) and sodium lauryl sulfate by a reasonable ratio, the tablet may achieve the right balance between lubricating effect and disintegration performance.
It should be noted sodium lauryl sulfate can not be applied to human intravenous formulations.
6, Fire extinguishing agent
Use as foaming agent.
For example, U.S. Patent 6,740,250 (Fire suppressant having foam stabilizer) describes a fire suppressant having foam stabilizer.
7, 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.
Sodium lauryl sulfate has good foaming property and water solubility. At the same time, sodium lauryl sulfate has good stability in a wide pH range.
So sodium lauryl sulfate is very suitable for use as floating agent in flotation process.
8, Emulsion polymerization
Emulsifier, particle size controlling agent in emulsion polymerization. For example, polyvinyl chloride emulsion polymerization.
9, Ore-dressing
Use as foaming agent, floating agent.
10, Textile, leather
Use as emulsifier, foaming agent, cleansing agent, wetting agent, antistatic agent, solubilizing agent.
11, Electroplating industry
Use as wetting agent (Anti-pinhole agent).
Can reduce or eliminate pinholes.
12, Paper Industry
Use as cooking penetrant, wastewater flocculant, deinking agent.
13, Pets
Main ingredient or auxiliary ingredient for cleansing agent, foaming agent in shampoos and other pet products.
14, Biochemistry
Use as protein denaturant.
15, Reagent
(1), Used as a standard substance, for example, in the following standard:
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), Sodium dodecyl sulfate - polyacrylamide gel electrophoresis
Manufacturers
References
[1]: HSDB. Sodium lauryl sulfate, 151-21-3
[2]: OECD. Category of Alkyl sulfates, Alkane Sulfonates and α-Olefin Sulfonates. SIDS Initial Assessment Report for SIAM 25. 2007.
[3]: 赵国玺 朱步瑶.表面活性剂作用原理.中国轻工业出版社,2003,P714
[4]: ChemIDplus. Sodium lauryl sulfate, 151-21-3
[5]: Cheol Heon Lee,Howard I. Maibach.Irritant Dermatitis.P257-267
[6]: P.W.A. Tovell. Absorption, metabolism and excretion by goldfish of the anionic detergent sodium lauryl sulphate. Toxicology, 4 (1975) 17-29
[7]: 郑琰晶,陈琳,陈燕平,黄韧.十二烷基硫酸钠对水生生物的急性毒性影响.农业环境科学学报,2006(S2)
[8]: 张克荣,李崇福,梁阳,何俊生.十二烷基硫酸钠在天然水体中的降解作用.中国卫生检验杂志,1999(03)
[9]: http://www.nicnas.gov.au. NICNAS Existing Chemicals Information Sheet: Sodium Lauryl Sulfate,2007
Update: 20131018(1); 20160710(2);