Sodium dodecyl benzene sulfonate (SDBS) is a commonly used anionic surfactant. It is a white or pale yellow powder or sheet solid, difficult to volatilize, easily soluble in water, and soluble in water to form a translucent solution.It is stable and slightly toxic to alkali, dilute acid and hard water.
Chinese name
Sodium dodecyl benzene sulfonate[9]
Foreign name
sodium dodecyl benzene sulfonate
HLB value
ten point six three eight
chemical formula
CeighteenHtwenty-nineNaOthreeS[9]
molecular weight
three hundred and forty-eight point four seven six[9]
In the late 1930s, benzene was alkylated with chlorinated petroleum, and then the alkylbenzene was sulfonated to produce alkylbenzene sulfonate.This was the first batch of industrial products of alkyl aryl sulfonates. At that time, most of the products were used in the textile industry, and then household formulas soon emerged.
After the Second World War, dodecylbenzene sulfonate appeared, which is a by-product of petroleum catalytic cracking.Tetrapolypropylene is prepared by reaction of benzene with tetrapolypropylene as alkylation reagent and sulfonation.
Because petrochemical companies can convert a large amount of tetrapolypropylene into dodecylbenzene, the product quality is high and the price is low, so the detergent with dodecylbenzene as the raw material quickly replaced soap, and dodecylbenzene sulfonate soon became the largest amount of organic surfactant in the United States. Although the surfactant used at this time has good application performance,However, there is generally a serious disadvantage, that is, their biodegradation rate in sewage treatment plants is very low, and the degradation is not complete, causing great pollution to the environment.In order to solve this problem, in the early 1960s, the detergent industry began to shift from the production of branched alkyl benzene sulfonates to linear alkyl benzene sulfonates.Due to the good biodegradability of straight chain products, the focus problem of detergent industry in the 1950s, namely the pollution caused by detergent foam, was solved.Since then, the application field of alkyl aryl sulfonate anionic surfactant has been expanding, and the demand and sales of products have been increasing.[1]
Physical and chemical properties
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physical property
Molecular formula: CeighteenHtwenty-nineNaOthreeS
Molecular weight: 348.48
Hydrophilic lipophilic balance value (HLB value): 10.638
Decomposition temperature: 450 ℃
Weight loss rate: 60%
Character: white or yellowish powder
Solubility: easily soluble in water, easy to absorb moisture and agglomerate
4. Hydrolysis is the reverse reaction of sulfonation.Under strong acid catalysis, sodium dodecylbenzene sulfonate can be co heated with water to remove the sulfonyl group, and the essence of the reaction is H+The electrophilic substitution reaction of attacking aromatic ring as electrophilic reagent.
Add 35mL (34.6g) of dodecylbenzene into a 250mL four necked bottle equipped with agitator, thermometer, dropping funnel and reflux condenser, slowly add 35mL of 98% sulfuric acid with a mass fraction under stirring, and the temperature shall not exceed 40 ℃. After addition, raise the temperature to 60~70 ℃, and react for 2h.
Lower the temperature of the above sulfonated mixed solution to 40~50 ℃, slowly add an appropriate amount of water (about 15mL), pour it into the separating funnel, stand still for a while, layer by layer, drain the lower layer (water and inorganic salt), and retain the upper layer (organic phase).
Prepare 80mL of 10% sodium hydroxide solution by mass fraction, add it into a 250mL four necked bottle of about 60~70mL, slowly add the above organic phase under stirring, control the temperature at 40~50 ℃, adjust pH=7~8 with 10% sodium hydroxide by mass fraction, and record the total amount of 10% sodium hydroxide by mass fraction.
In the above reaction system, a small amount of sodium chloride is added, the permeation circle test is clear, and then filtered to obtain a white paste product, namely sodium dodecyl benzene sulfonate.[3]
The relevant chemical reactions are:
Sodium dodecyl benzene sulfonate
Industrial process
Sodium dodecylbenzene sulfonate is prepared by sulfonating dodecylbenzene with fuming sulfuric acid or trioxide and neutralizing with alkali.The disadvantage of sulfonation with fuming sulfuric acid is that there is always some waste acid in the sulfonation material after the reaction.The sodium sulfate generated after neutralization is brought into the product, affecting its purity.At present, sulfur trioxide air mixture sulfonation method is adopted in industry.Sulfur trioxide can be evaporated from 60% fuming sulfuric acid, or sulfur and dry air can be burned in the furnace to obtain SOthreeGas mixture of.The mixed gas is introduced into the sulfonation reactor with alkyl benzene for sulfonation.Sulfonated materials enter the neutralization system for neutralization with sodium hydroxide solution, and finally enter the spray drying system for drying.The product obtained is a powder with good fluidity.
Production process flow:
Sodium dodecyl benzene sulfonate
Sodium dodecyl benzene sulfonate
After dehydrogenation of straight run kerosene, dodecyl alkenes and benzene enter the alkylator from the feed pump, and then the generated dodecyl benzene (LAB) is sent to the sulfonator 1, where it reacts with sulfur trioxide (3%~5%) entering the sulfonator instantly. After being treated by gas-liquid separator 2, circulating pump 3, and cooler 4, some of the products return to the bottom of the reactor for rapid cooling of sulfonic acid,Part of the reaction products are sent to the aging device 5, the reaction holding time is adjusted, and then enter the hydration device 6 to form acid, and finally through the neutralizer 7 to produce sodium alkylbenzene sulfonate (LAS).The tail gas goes through demister 8 to remove acid mist, and then through absorption tower 9 to vent.[4]
application area
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Washing action
Sodium alkylbenzene sulfonate is a yellow oily substance, which can form hexagonal or square strong lamellar crystals after purification, with slight toxicity, and has been recognized as a safe chemical raw material by the international safety organization.Sodium alkylbenzene sulfonate can be used in the cleaning of fruits and tableware. The amount of sodium alkylbenzene sulfonate used in detergents is the largest. Due to the large-scale automatic production, the price is low. There are two types of sodium alkylbenzene sulfonate used in detergents: branched chain structure (ABS) and linear chain structure (LAS). The branched chain structure has little biodegradability and will cause environmental pollution, while the linear chain structure is easy to be biodegradable,Biodegradability can be more than 90%, with little environmental pollution.
Sodium dodecyl benzene sulfonate is neutral, sensitive to water hardness, not easy to oxidize, strong foaming power, high decontamination power, easy to mix with various additives, low cost, mature synthesis process, wide application field, and is a very excellent anionic surfactant.Sodium dodecyl benzene sulfonate has significant decontamination effect on particle dirt, protein dirt and oily dirt, especially on particle dirt on natural fibers. Its decontamination power increases with the increase of washing temperature, and its effect on protein dirt is higher thanNonionic surfactantAnd rich in foam.However, sodium dodecyl benzene sulfonate has two disadvantages. First, it has poor resistance to hard water, and its decontamination performance can be reduced with the hardness of water. Therefore, the detergent with its main active agent must be mixed with an appropriate amount ofChelating agentMatching.The second is that the degreasing force is strong, and it is irritating to the skin when washed by hand. The hand feeling of the clothes after washing is poor, so it is suitable for useCationic surfactantRinse with softener.In recent years, in order to obtain better comprehensive washing effect, sodium dodecylbenzene sulfonate is often used in combination with non-ionic surfactants such as fatty alcohol polyoxyethylene ether (AEO).The main use of sodium dodecyl benzene sulfonate is to prepare various types of liquid, powder and granular detergents, cleaning agents andCleaning agentEtc.[4]
Emulsifying dispersant
Emulsifier is a substance that can improve the surface tension between various constituent phases in emulsion to form a uniform and stable dispersion system or emulsion.Emulsifiers are surface active substances, with both hydrophilic and lipophilic groups in the molecule. They gather at the oil/water interface, which can reduce the interfacial tension and reduce the energy required to form emulsions, thus increasing the energy of emulsions.As an anionic surfactant, sodium dodecyl benzene sulfonate has good surface activity and strong hydrophilicity, which can effectively reduce the tension of oil-water interface and achieve emulsification.Therefore, sodium dodecyl benzene sulfonate is widely used in emulsion preparation of cosmetics, food, printing and dyeing auxiliaries, pesticides, etc.[4]
Antistatic agent
Any object has its own static charge, which can be either negative or positive. The accumulation of static charges will affect or even endanger life or industrial production. The chemicals that guide and eliminate the accumulated harmful charges will not cause inconvenience or harm to production and life are called antistatic agents.Sodium dodecyl benzene sulfonate is an anionic surfactant, which can make the surface of fabrics, plastics, etc. hydrophilic. At the same time, the ionic surfactant has a conductive effect, so it can make static electricity leak in time, thus reducing the danger and inconvenience caused by static electricity.[4-5]
Other roles
Sodium dodecyl benzene sulfonate is widely used. In addition to the above applications, it is also often used as a cotton fabric refining agent, desizing agent, leveling agent in dyeing, and metal degreasing agent in the process of metal electroplating;Used as resin dispersant, felt detergent and deinking agent in paper industry;Used as penetrating degreaser in leather industry;Used as anti caking agent in fertilizer industry;In the cement industry, it is used as air entraining agent and other aspects, either alone or as a matching component.[6]
Safety measures
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Dangerous goods sign
Xn: Harmful
Risk terminology
R22: Harmful if swallowed.
R41: Serious injury to eyes.
R37/38: Irritating to respiratory system and skin.
Safety terminology
S26: In case of contact with eyes, please wash with plenty of water immediately and ask for doctor's advice.
S27: Once the clothes are contaminated, please take them off immediately.
S36/37/39: Wear appropriate protective clothing, gloves and goggles or mask.
Substance toxicity
Low toxicity, median lethal dose: 1260 mg/kg (rat by mouth)[7]
Hazard Overview
Health hazard: This product is basically non-toxic.Its concentrated solution has a certain irritating effect on the skin.At present, there is no report of occupational poisoning.
Explosion hazard: explosion hazard.
First aid measures
Skin contact: Take off contaminated clothes and wash with plenty of flowing water.
Eye contact: lift the eyelid, wash with flowing water or physiological saline, and seek medical advice.
Inhalation: leave the site to a place with fresh air;If breathing is difficult, give oxygen and seek medical advice.
Ingestion: drink enough warm water to induce vomiting.Get medical attention.
Fire fighting measures
Hazard characteristics: flammable in case of open fire and high heat.It can react with oxidants.Toxic gas is released due to high thermal decomposition.
Extinguishing method: firefighters must wear gas masks and full body fire-fighting clothes to extinguish the fire in the upwind direction.Extinguishing agent: fog water, foam, dry powder, carbon dioxide, sand.
Leakage emergency treatment
Isolate the leakage contaminated area and restrict access.Cut off the ignition source.It is recommended that emergency personnel wear dust masks (full face masks) and gas suits.Avoid flying dust, sweep it carefully, put it in a bag and transfer it to a safe place.In case of large leakage, cover it with plastic cloth and canvas.Collect and recycle or transport to waste disposal site for disposal.[8]
matters needing attention
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Operation precautions
Close operation and strengthen ventilation.Operators must be specially trained and strictly abide by the operating procedures.It is recommended that operators wear self-priming filter type dust mask, chemical safety goggles, anti poison penetration work clothes and rubber gloves.Keep away from kindling and heat sources, and smoking is strictly prohibited in the workplace.Use explosion-proof ventilation systems and equipment.Avoid dust generation.Avoid contact with oxidants.Load and unload gently during transportation to prevent damage to packaging and containers.Fire fighting equipment and leakage emergency treatment equipment of corresponding types and quantities shall be provided.Empty containers may leave harmful substances.
Precautions for storage
Store in a cool and ventilated warehouse.Keep away from kindling and heat sources.It shall be stored separately from oxidant and shall not be mixed.Equip with corresponding types and quantities of fire-fighting equipment.The storage area shall be equipped with appropriate materials to contain leakage.[8]
