Sebacic acid ( decanilic acid ) HOOC (CH 2 ) 8 COOH - dibasic carboxylic acid ( Latin sebaceus - candle oil, lard). It has all the chemical properties characteristic of carboxylic acids . The salts and esters of sebacic acid are called sebacinates .
| Sebic acid | |
|---|---|
| Are common | |
| Systematic name | decanedioic acid, 1,8-octane dicarboxylic acid |
| Traditional names | sebacic acid |
| Chem. formula | C₁₀H₁₈O₄ |
| Rac formula | HO 2 C (CH 2 ) 8 CO 2 H |
| Physical properties | |
| condition | crystalline |
| Molar mass | 202.25 g / mol |
| Density | 1,209 g / cm³ |
| Thermal properties | |
| T. melt. | 134–135 ° C |
| T. Kip. | (at 10 mm of mercury. ) 232 ° C |
| T. | 280—300 ° C |
| T. sspl. | 332 ° C |
| Enthalpy of combustion | |
| Chemical properties | |
| pK a | K 1 2.38⋅10 −5 ; K 2 0,26⋅10 −5 |
| Water solubility | 0.1 g / 100 g (15 ° C); 2 g / 100 g (100 ° C) |
| Structure | |
| Dipole moment | 8.3⋅10 −30 Cl · m |
| Classification | |
| Reg. CAS number | |
| Pubchem | |
| Reg. EINECS number | |
| SMILES | |
| Inchi | |
| RTECS | |
| CHEBI | and |
| Chemspider | |
Content
Getting
First obtained in 1802 by Tenar during the dry distillation of pork fat .
In industry, sebacic acid is produced mainly from castor oil . When heated with water (200-225 ° C; 1.8-2.5 MPa), glycerol and a mixture of carboxylic acids containing 80-85% ricinolic acid are formed ; decomposition of the latter with alkali at 250 ° C followed by saponification of the formed sodium sebacicate with mineral acids leads to the release of sebacic acid (yield 35-40% per castor oil).
A promising method for producing sebacic acid is the anodic condensation of monomethyl adipate to dimethyl sebacate, followed by hydrolysis of the diester:
The process is carried out in methanol on platinized titanium electrodes at a current density of 600–1500 A / m², a temperature of 45–55 ° C, and the diester is hydrolyzed in an excess of water (220–240 ° C; 3.9–4.9 MPa); the output of sebacic acid in this case is 70-75%.
Sebacic acid can also be obtained by oxidation of cyclodecane HNO 3 or from 1,3-butadiene and ethylene according to the scheme:
Properties
When sebacic acid is reduced, 1,10-decanediol is formed ; under the action of Br 2 on silver sebacate - 1,8-dibromoctane ; during the dehydration of the ammonium salt or diamide - sebacinodinitrile . Heating sebacic acid with acetic anhydride leads to the formation of an unstable polymeric anhydride, which cleaves CO 2 and turns into cyclononanone .
Sebacic acid is capable of polycondensation with bifunctional compounds: with glycols it forms polyesters [-OROCO (CH 2 ) 8 CO-] n ; with diamines and amino alcohols , the corresponding polyamides and polyether amides [-XRNHCO (CH 2 ) 8 CO-] n (X = O, NH).
The decarboxylation temperature is 350-370 ° C.
Combustion enthalpy (Δ H 0 burn ) −5409.4 kJ / mol.
Application
Sebacic acid is used in industry for the production of polyhexamethylene sebacamide (nylon-1.6), polyester fibers and adhesives, as a stabilizer for alkyd resins. Used in the manufacture of hydraulic fluids, cosmetics, candles, etc. It is also an intermediate in the production of antiseptics . From sebacic acid esters, dibutyl and dioctyl sebacates are used as PVC plasticizers , diisobutyl sebacate is a plasticizer of a number of elastomers . Di (2-ethylhexyl) sebacate is part of the oils and lubricants used at low temperatures.
Sebacic acid esters are flammable, low-toxic substances; for dibutyl sebacate LD 50 25.5 g / kg; for dioctyl sebacate - 19.6 g / kg, MPC - 10 mg / m³.
The total global capacity of the existing lines for the production of this substance and its derivatives today is approaching 170 thousand tons per year [1] .
Literature
- Clara G., Fritzsche E., Grebe F., Synthetic polyamide fibers, trans. with him., M., 1966.
- Freidlin, GN, Aliphatic Dicarboxylic Acids, M., 1978. S. K. Smirnov.
- Aliphatic dicarboxylic acids, M., 1978. S. K. Smirnov.