Stearic acid, chemical formula CeighteenHthirty-sixOtwo, with a molecular weight of 284.48, is a compound, namely octadecanoic acid.fromOil hydrolysisProduction, mainly used to produce stearate.
Chinese name
stearic acid[4]
Foreign name
stearic acid[4]
Alias
Octadecanoic acid[4]
chemical formula
CeighteenHthirty-sixOtwo[4]
molecular weight
two hundred and eighty-four point four eight
CAS login number
57-11-4[4]
EINECS login number
266-928-5[4]
Melting point
67 to 72 ℃[4]
Boiling point
361 ℃[4]
Water solubility
Insoluble
Density
0.84 g/cm³
Appearance
White waxy transparent solid or yellowish waxy solid
PubChem No：twenty-four million eight hundred and ninety-nine thousand six hundred and sixteen[1]
Physical property data
Announce
edit
1. Character: white waxy transparent solid or yellowish waxy solid.It can be dispersed into powder with slight smell of butter.
2. Density: 0.84g/cmthree
3. Melting point: 67~72 ℃
4. Boiling point: 361 ℃
5. Refractive index（ntwentyD）：1.455
6. Gas phase standard combustion heat (enthalpy): - 11446.9 kJ · mol-1
7. Gas phase standard heat of formation (enthalpy): -781.2 kJ · mol-1
8. Standard combustion heat of liquid phase (enthalpy): - 11343.4 kJ · mol-1
9. Standard heat of formation of liquid phase (enthalpy): -884.7 kJ · mol-1
10. Standard combustion heat of crystalline phase (enthalpy): - 11280.4 kJ · mol-1
11. Standard heat of formation of crystal phase (enthalpy): -947.7 kJ · mol-1
12. Solubility: insoluble in water, slightly soluble in cold ethanol, easily soluble when heated.Slightly soluble in acetone, benzene, easily soluble in ether, chloroform, hot ethanolcarbon tetrachloride、carbon disulfide。[1]
toxicology data
Announce
edit
Intravenous injection of LC into mice and ratsfifty：(23±0.7)mg/kg、(21.5±1.8)mg/kg。[1]
Molecular structure data
Announce
edit
1. Molar refractive index: 87.00[4]
2. Molar volume (cmthree/mol）：320.2
3. Isotonic specific volume (90.2K): 770.0
4. Surface tension (dyne/cm): 33.4
5. Polarization (10-24cmthree）：34.49[2]
Calculate chemical data
Announce
edit
1. Calculation reference value of drainage parameter (XlogP): 7.4
2. Number of hydrogen bond donors: 1
3. Number of hydrogen bond receptors: 2
4. Number of rotatable chemical bonds: 16
5. Number of tautomers: 0
6. Topological molecule polar surface area (TPSA): 37.3[4]
11. Determine the number of atomic structure centers: 0
12. Number of uncertain atomic structure centers: 0
13. Determine the number of chemical bond structural centers: 0
14. Number of indeterminate chemical bond structure centers: 0
15. Number of covalent bond units: 1[2]
Inspection method
Announce
edit
Water soluble acid: take 5g of this product, heat it to melt, add new boiling hot water of equal volume, shake it for 2 minutes, cool it, filter it, add 1 drop of methyl orange indicator solution to the filtrate, and it shall not appear red.
Neutral fatOr wax: take 1.0g of this product and add watersodium carbonate0.5g and 30mL of water, boil to dissolve, and the solution should be clear.
Residue on ignition: Take 4.0g of this product and check it according to the law (Appendix VIII N). The residual residue shall not exceed 0.1%.
Heavy metal: take the residue left under the item of ignition residue, and check according to the law (Annex VIII H, the second method), includingheavy metalNot more than five parts per million.[1]
It exists in flue-cured tobacco, burley tobacco, oriental tobacco and smoke.
four
It is the fatty acid that makes up stearin.[2]
Storage method
Announce
edit
1. 200 stearic acid is packed in cardboard box.Type 800 stearic acid is packed in woven bags lined with plastic bags.Store in a cool and ventilated place.
2. This product can be packed in cardboard boxes or woven bags lined with plastic bags.The net weight of each box (bag) is 25kg or 50kg.
3. Store in a cool, dry and ventilated place, and keep away from fire sources and oxidants.Store and transport according to general chemical regulations.[2]
synthetic method
Announce
edit
Stearic acid is a kind of fatty acid that widely exists in nature. Almost all fats contain stearic acid with different contents. It has a high content in animal fat, such as 24% in butter, less in vegetable oil, 0.8% in tea oil, 6% in palm oil, but 34% in cocoa butter.The production methods of industrial stearic acid mainly include fractionation method and pressing method.A decomposing agent is added into the hardening oil, and then the crude fatty acid is obtained by hydrolysis, and then the finished product is obtained through water washing, distillation and decolorization.At the same time, glycerol is a by-product.
(1) With fractionation method, 6t cottonseed oil hardening oil and 120kg hydrolysis agents cresol sulfonate stearate and naphthalene sulfonate stearate were added into the hydrolysis pot.Add 4200kg of water after injecting steam to the transparent oil layer.Continue heating to boiling, react for 7.5h under normal pressure, clarify for 0.5h, and separate the glycerol water in the lower layer.Then add 120kg of hydrolytic agent, heat the oil layer with steam until it is transparent, add 3600kg of water, and react for about 10h. When the mixed acid value reaches above 190mg KOH/g, it is the hydrolysis end point.After that, it was clarified for 0.5h. After separating glycerol water, it was washed with 7kg salt and 3600kg water.Then use 14kg salt and 4200kg water for secondary water washing.Clarify for 0.5h after the first step of washing, and for 2h after the second step of washing.After the lower layer of acid water is divided, take the upper layer of mixed fatty acid for standby.[3]
Add 2000kg of mixed fatty acid into a distillation kettle for vacuum fractionation. The kettle temperature is 250-255 ℃, the tower temperature is 210-220 ℃, the top temperature is 200-210 ℃, and the tower top residual pressure is 0.53-0.93kPa.After the balance of feeding, discharging and discharging is reached, the continuous operation will be carried out, with feeding 100%, discharging 40% and discharging 60%.It is used to make tertiary stearic acid.After analyzing that the iodine value of the discharged material is below 2mg/100g, put 1000kg stearic acid and 3kg 92.5% sulfuric acid into the pickling pot in turn, boil and wash.After cutting off the acid foot, take 450kg of stearic acid and put it into the decoloring pot to heat it to 190 ℃, and then add 150mL of chemical soda ash and 11kg of dry clay successively, and decolorize it for about 45min at about 105 ℃ under reduced pressure mixing.The primary stearic acid is obtained through filter pressing and pouring plate forming.
The glycerol water separated from the hydrolysis process is neutralized with lime milk at 80-100 ℃, and refined glycerol can be obtained through such processes as suction filtration concentration, pressure filtration, vacuum distillation, activated carbon decoloration and pressure filtration.
(2) The pressing method takes animal and vegetable oils as raw materials, and the primary stearic acid is prepared by high-pressure hydrolysis, washing, vacuum distillation, pressing, bleaching crystallization and other processes in the presence of hydrolytic agents (such as zinc oxide).
(3) In the presence of decomposing agents (benzene, naphthalene and other sulfonated mixtures), the hardened oil, beef fat or sheep fat is hydrolyzed, and then acidified, distilled, pressed and pickled to obtain the finished product.
(4) Use oleic acid hydrogenation method.
(5) Use synthetic fatty acid Cten～CtwentyAnd Ceighteen～CtwentyThe distillate is made from raw materials by melting, pickling (using 1% sulfuric acid) molding, pressing, melting, pickling, dehydration and crystallization.
In addition, it can also be used as solvent for oil soluble pigments, crayon smoothing agent, wax paper polishing agent, emulsifier for stearic acid glyceride, etc.
The product is used in the food industry as a lubricant, defoamer and raw material for food additives such as glyceride stearate, sorbitan stearate, sucrose ester, etc.Used as raw materials for additives and daily chemical products.
Stearic acid is widely used in the manufacture of PVC plastic pipes, plates, profiles and films.It is a PVC heat stabilizer with good lubricity and good light and heat stability.In plastic PVC pipes, stearic acid helps to prevent "coking" during processing. Adding stearic acid in PVC film processing is an effective heat stabilizer, and can also prevent discoloration of finished film caused by exposure to sulfide.
rubber industry
Stearic acid plays an important role in the synthesis and processing of rubber.Stearic acid is natural gumsynthetic rubberAnd widely used in latexVulcanizing active agentIt can also be used as plasticizer and softener.Stearic acid needs to be added as emulsifier during the production of synthetic rubberFoam rubberStearic acid can be used as foaming agent and stearic acid can also be used asRubber productsRelease agent.
Cosmetics industry
Stearic acid is used in two types of skin care products, namely, snow cream and cold cream, to emulsify, so that it can become a stable and white cream.Stearic acid is also the main raw material for almond honey and milk.Stearic acid soap esters are more widely used in cosmetics industry.[2]
Other related
Announce
edit
Fatty acids are mainly used as the basic raw materials of surfactants and are widely used in: rubber industry as vulcanizing activator;The plastic industry is used as lubricant and stabilizer;Used as softener and bactericide in textile industry and household detergent;It is used as wax pattern in precision casting and soap base in lubricating grease industry.
In the cosmetics industry, it is an indispensable raw material for manufacturing general emulsified products, which is used to prepare cream, cold cream, foundation, shaving cream, hair cream and skin care emulsion.In the rubber industry, it is the vulcanizing active agent of natural rubber, synthetic rubber and latex, and also used as a softener.It is used as plasticizer, stabilizer and lubricant in plastic industry.It is used as yarn lubricant and mercerizing paste softener in textile industry.It is also used to manufacture release agent, polishing paste, defoamer, metal flotation agent, paint polish agent, wax paper polish agent, textile waterproof agent and other products. It is a solvent for oil soluble pigments and also a manufacturing agentMethyl stearate、Calcium stearate、Potassium stearateAnd other stearates and stearates.This product is non-toxic, and is packed in woven bags or cartons lined with plastic bags, each bag (or carton) has a net weight of 25kg and 50kg.It shall be stored and transported according to the provisions of general chemicals and stored in a cool and dry place.[2]
industrial products
Industrial products are white or yellowish particles or lumps, accounting for 45% stearic acid and 55%Palmitic acidAnd contains a small amount of oleic acid, with a slightly fatty smell.Industrial products can be divided into primary (formerly called tertiary pressing, after tertiary pressing), secondary (formerly called secondary pressing, after secondary pressing) and tertiary (formerly called primary pressing, after primary pressing or without pressing).It is a mixed acid mainly composed of stearic acid and palmitic acid.The primary and secondary stearic acids are white waxy solids with gloss or crystals.Tertiary stearic acid is a yellowish waxy solid.
S16 Keep away from sources of ignition。Keep away from ignition sources.
S26 In case of contact with eyes, rinse immediately with plenty of water and seek medical advice。In case of contact with eyes, please immediately flush with plenty of water and seek medical advice.
S37/39 Wear suitable gloves and eye/face protection。Wear appropriate gloves and goggles or mask.[2]
Risk terminology
Announce
edit
R11 Highly flammable。Highly flammable.
R36/37/38 Irritating to eyes, respiratory system and skin。Irritating to eyes, respiratory system and skin.[2]
quality standard
Announce
edit
Stearic acid (quality standard:
Complying to the Standard of GB9103-88
Index name Index value Model Y-4Y-8Y-10 Freezing point ℃ 52 ≤ x ≤ 57
