弗雷拉纳标准品025
2-Methyl-1,4-benzenedicarboxylic acid
CAS: 5156-01-4
Molecular Formula: C9H8O4
弗雷拉纳标准品025 - Names and Identifiers
弗雷拉纳标准品025 - Physico-chemical Properties
| Molecular Formula | C9H8O4 |
| Molar Mass | 180.16 |
| Density | 1.377 |
| Melting Point | 323-325 °C |
| Boling Point | 388.2±30.0 °C(Predicted) |
| Flash Point | 202.8℃ |
| pKa | 3.38±0.25(Predicted) |
| Storage Condition | Sealed in dry,Room Temperature |
弗雷拉纳标准品025 - Risk and Safety
| HS Code | 29173990 |
弗雷拉纳标准品025 - Reference Information
| application | 2-methyl -1,4-phthalic acid can be used as an intermediate in pharmaceutical and chemical synthesis. Such as the synthesis of dimethyl 2-methyl terephthalate. Dimethyl 2-methylterephthalate is an important compound in the process of synthesizing vinyl terephthalic acid crustacean liquid crystal polymer. At present, most of them are synthesized by acid catalysis. The yield is relatively low, only about 33%, and the loss of raw materials is relatively large. Since dimethyl 2-methylterephthalate is a necessary intermediate for the synthesis of vinyl terephthalic acid crustacean liquid crystal polymers, it is of great significance to improve its yield, but most acid-catalyzed esterification reactions have the problem of low conversion rate. In this reaction, methanol is used as both a reaction reagent and a solvent. The boiling point of methanol is low, and no suitable water-carrying agent can be found to use the oil-water separator to remove water. Therefore, on the basis of existing research, adding anhydrous copper sulfate powder with strong water absorption, anhydrous copper sulfate can combine 3 water molecules at 80 ℃, which improves the esterification conversion rate. The results of infrared IR and nuclear magnetic resonance NMR analysis of the obtained product show the correctness of the synthesized compound, which lays the foundation for the next step of mass synthesis of vinyl terephthalic acid crustacean liquid crystal polymer |
| preparation method | the specific preparation method is as follows: 2-methyl terephthalic acid is used as raw material, and the following steps are included in sequence: 1) esterification: under the catalysis of concentrated sulfuric acid, 2-methyl terephthalic acid and methanol undergo esterification reaction at 80 ℃, the reaction time is 8h ~ 12h, and the material ratio of 2-methyl terephthalic acid and methanol is 1:10;2) Water absorption: anhydrous copper sulfate is used as the water absorbing agent, and anhydrous copper sulfate is added to the above mixture. The weight ratio of 2-methyl terephthalic acid and anhydrous copper sulfate is 20:17~1:1;3) Extraction: Dichloromethane is used as the extractant to separate the lower organic phase; 4) Recrystallization: Recrystallization the obtained crude dimethyl 2-methyl terephthalate in petroleum ether to obtain dimethyl 2-methyl terephthalate. |
Last Update：2024-04-09 21:01:54
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Product Name: 2-Methyl-1,4-benzenedicarboxylic acid Visit Supplier Webpage Request for quotationCAS: 5156-01-4
Tel: 18301782025
Email: 3008007409@qq.com
Mobile: 18021002903
QQ: 3008007409
Wechat: 18301782025
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