Name | Maleic acid |
Synonyms | Maleic acid acidemaleique Kyselina maleinova (z)-butenedioicaci Cis-Butenedioic acid Butenedioic acid,(Z)- 2-Butenedioicacid(Z)- cis-2-Butenedioic acid (2Z)-but-2-enedioic acid (2E)-but-2-enedioic acid methylidenepropanedioic acid 1,2-ethylenedicarboxylicacid,(z) cis-Ethylene-1,2-dicar-boxylicacid 1,2-Ethylenedicarboxylic acid, (Z) |
CAS | 110-16-7 |
EINECS | 203-742-5 |
InChI | InChI=1/C4H4O4/c5-3(6)1-2-4(7)8/h1-2H,(H,5,6)(H,7,8)/b2-1+ |
InChIKey | VZCYOOQTPOCHFL-OWOJBTEDSA-N |
Molecular Formula | C4H4O4 |
Molar Mass | 116.07 |
Density | 1.59 g/mL at 25 °C (lit.) |
Melting Point | 130-135 °C (lit.) |
Boling Point | 275°C |
Flash Point | 127 °C |
Water Solubility | 790 g/L (25 ºC) |
Solubility | Soluble in water, ethanol and acetone, insoluble in benzene. |
Vapor Presure | 0.001Pa at 20℃ |
Appearance | Colorless crystal |
Specific Gravity | 1.59 |
Color | White |
Merck | 14,5703 |
BRN | 605762 |
pKa | 1.83(at 25℃) |
PH | 3.05(1 mM solution);2.21(10 mM solution);1.54(100 mM solution); |
Storage Condition | Store below +30°C. |
Stability | Stable. Combustible. Incompatible with strong oxidizing agents, bases. |
Sensitive | Easily absorbing moisture |
Refractive Index | 1.5260 (estimate) |
MDL | MFCD00063177 |
Physical and Chemical Properties | Monoclinic colorless crystal, astringent. relative density (water = 1) 1.59(20 ℃) relative vapor density (Air = 1) 4.0 |
Use | Preparation of pesticide marathon, up to the net of pine, fumaric acid, unsaturated polyester resin, dyeing auxiliaries and oil preservatives, can also be used for synthetic resin and pesticides. |
Hazard Symbols | Xn - Harmful |
Risk Codes | R22 - Harmful if swallowed R36/37/38 - Irritating to eyes, respiratory system and skin. R43 - May cause sensitization by skin contact |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S28 - After contact with skin, wash immediately with plenty of soap-suds. S37 - Wear suitable gloves. S28A - S46 - If swallowed, seek medical advice immediately and show this container or label. S24 - Avoid contact with skin. |
UN IDs | 3261 |
WGK Germany | 1 |
RTECS | OM9625000 |
TSCA | Yes |
HS Code | 29173990 |
Hazard Class | 8 |
Packing Group | III |
Raw Materials | Benzene |
Downstream Products | Fumaric acid DL-Malic acid Timolol Enalapril trimebutine maleate 2-Phosphonobutane-1,2,4-tricarboxylic acid |
Reference Show more | 1. Wang Liying, Zhang Xu, Sun Junmin, et al. Preparation of long-term stable aqueous dispersion of high molecular weight amphoteric polyacrylamide. |
monoclinic colorless crystal, astringent. The melting point was 130-130.5 °c. Decomposition at about 138 °c. Relative density (d20) 1.590. Soluble in water, ethanol and acetone, insoluble in benzene.
This product is maleic acid. The content of maleic acid shall not be less than 99.0%, calculated as anhydrous.
The melting point of this product (General 0612) is 133.0~137. 0 "C.
mainly used in the production of pesticide marathon, up to the net Pine, the synthesis of unsaturated resin and tartaric acid, succinic acid and other products, but also used in coatings, food and printing and dyeing auxiliaries.
CIS acid is toxic and irritates the skin and mucous membranes, causing conjunctival and corneal redness, vision loss and even blindness. Skin contact with liquid acid, can cause burns. The oral LD50 in rats was 708mg/kg. Wear protective equipment during operation, and the equipment should be sealed to prevent running
Leakage, the site should have good ventilation conditions. Wash with plenty of water after contamination with CIS acid. Fire should be used with water or CO2 spray when fire, can not use nahco3 fire extinguisher, because it is easy to cause rapid decomposition of CIS acid.
The product is packed with woven bag lined with plastic bag, and the net weight of each bag is 25kg. Pay attention to moisture, away from fire and alkaline substances.
take 0 .5g of this product, add water 1 0 m l, shake to dissolve, and determine according to law (General rule 0631), p H value shall not exceed 2.0.
take this product l.O g, add 0901 of water to dissolve, check according to law (General rule 0902 and general rule 0901), the solution should be clear and colorless; If the color is colored, with the yellow No. 1 Standard Colorimetric solution (General rule first method) comparison, not deeper.
take an appropriate amount of this product, precision weighing, and add mobile phase to dissolve and quantitatively dilute to prepare a solution containing about lm g per lm l as a test solution; in addition, the appropriate amount of maleic acid and fumaric acid reference substance was carefully weighed, and the mobile phase was added for dissolution and quantitative dilution to prepare a solution containing 1 punch and 5 Qiu for each lm l, which was used as the reference solution. Tested according to high performance liquid chromatography (General 0512). Silica gel bonded with eighteen alkyl silane was used as filler; Water (p H value adjusted to 3 ,0 with phosphoric acid)-acetonitrile (85: 15) was used as mobile phase; Detection wavelength: 210nnn
Take 10 0 solution of reference substance and inject it into human Liquid Chromatograph. The resolution of fumaric acid peak and maleic acid peak should be more than 2.5. Then the sample solution and the reference solution were respectively 10 ^ 1, and the human liquid chromatograph was injected respectively, and the chromatogram was recorded to 2 times of the retention time of the maleic acid peak. The sample solution chromatogram showed impurity peaks. According to the external standard method to calculate the peak area, containing fumaric acid should not exceed 0 .5%, Other single impurities in the reference solution of maleic acid peak area calculation should not exceed 0 .1%, the total amount of impurities should not exceed 1,0%.
take this product, according to the determination of moisture (General rule 0832 first method 1), the water content shall not exceed.
This product l .O g, inspection according to law (General 0841), residue shall not exceed 0.1%.
take this product l .O g, add 25ml water, check according to law (General Rule 0 8 0 7 ) , and standard iron solution 0. Compared with the control solution made of 5m l, it should not be deeper (0. 0005%).
The residue left under the item of taking the ignition residue shall not contain more than 10 parts per million of heavy metal when examined by law (General Principles 0821, Law II).
take this product about l .O g, precision weighing, add 100ml of water to dissolve, add several drops of phenolphthalein indicator solution, titrate with sodium hydroxide titration solution (lm o l/L), each lm l sodium hydroxide titration solution (lm o l/L) corresponds to 58.04mg of C4h4O4.
pharmaceutical excipients, p H value regulator and effervescent agent.
sealed storage.
LogP | -1.3 at 20℃ |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
Introduction | Maleic acid is maleic acid, which is a dicarboxylic acid, that is, an organic compound containing two carboxylic acid functional groups. Maleic acid and fumaric acid (fumaric acid) are cis-trans isomers. Maleic acid is often used to prepare fumaric acid. The anhydride of maleic acid is maleic anhydride. Compared with its anhydride, maleic acid has fewer applications. |
Characteristics | Maleic acid is less stable than fumaric acid. Maleic acid is 22.7kJ · mol − 1, and fumaric acid is -1355 kJ/mole. The solubility of maleic acid in water is better than that of fumaric acid, and the melting point of maleic acid (135 ℃) is much lower than that of fumaric acid (287 ℃). Intramolecular hydrogen bonds can explain the difference between these two properties. |
Toxicity | Maleic acid may inhibit certain enzymes in metabolism, such as transaminase of amino acid metabolism, and amino acid metabolism is mainly in the liver and kidneys, so long-term intake of maleic acid may cause liver and kidney damage; in addition, in the citric acid cycle of mitochondria, certain enzymes may also be affected by maleic acid. In animal experiments, it will cause damage to the renal tubules of dogs, produce irreversible damage. In animal tests, the degree of injury is proportional to the dose and intake time. |
use | maleic acid, also known as maleic acid, is mainly used to produce pesticide marathon, dahongsong, synthetic unsaturated polyester resin, rosin, tartaric acid, fumaric acid, succinic acid and other products, and is also used in pharmaceuticals, coatings, food, printing and dyeing auxiliaries and grease preservatives. Alkalometric analysis standard, slow oil and fat rancidity can be used as oil and oil preservatives, organic synthesis. |
production method | 1. after preheating, pure benzene by benzene oxidation method is oxidized by air under the action of vanadium series catalysts to generate maleic anhydride (hereinafter referred to as maleic anhydride), the reaction temperature is 360 ℃, and then the maleic acid product is obtained by water absorption, concentration, crystallization and drying. 2. Butene (alkane) oxidation method Butene (alkane) is oxidized by air to generate maleic anhydride under the action of vanadium-based catalyst. The reaction temperature is 350-450 ℃, and then it is absorbed by water to generate cis acid, and then concentrated and dried to obtain the finished product. 3. Other production methods (1) When naphthalene or o-xylene is oxidized to phthalic anhydride, it is a by-product of cis-acid;(2) Furfural oxidation method, which is not used due to benefit problems. |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |