- Technology Introduction
Dimethyl carbonate (DMC) is an important organic chemical intermediate and is widely used in organic synthesis reactions such as carbonylation, methylation, methoxylation and carbonyl methylation. Since DMC is non-toxic, it can replace highly toxic phosgene, methyl chloroformate, dimethyl sulfate, etc. as a methylating agent or carbonylating agent to improve the safety of production operations and reduce environmental pollution. As a solvent, DMC can replace Freon, trichloroethane, trichlorethylene, benzene, xylene, etc. in paints, coatings, cleaning solvents, etc. As a gasoline additive, DMC can increase its octane number and oxygen content, thereby improving its anti-knock properties. In addition, DMC can also be used as an additive for detergents, surfactants and softeners.
In the process of synthesizing dimethyl carbonate by oxidative carbonylation of methanol, in addition to DMC, the prepared reaction solution also contains a large amount of unreacted raw materials and by-products (such as formaldehyde, trimerformaldehyde, etc.), which require further separation to obtain DMC products.
Since the raw materials contain impurities such as formaldehyde and parformaldehyde, these impurities have a significant impact on the subsequent distillation process and equipment selection. Therefore, a pretreatment device needs to be used to remove formaldehyde and parformaldehyde in advance. The material after removing formaldehyde and parformaldehyde enters the subsequent process. distillation system.
For the removal of formaldehyde and paraformaldehyde, since methanol and DMC form an azeotrope, ordinary distillation cannot obtain pure products. Therefore, a combination of two-step separation is usually used: the first step is the initial distillation stage, using azeotropic distillation. In the form of distillation, the methanol-DMC azeotrope is obtained by distillation in a packed tower, and other products are separated; the second step is the refining stage, using effective separation methods to break the azeotrope to obtain DMC. The main methods include low-temperature crystallization and extraction. Distillation method, azeotropic distillation method, pressure distillation method, etc., to obtain high-purity DMC products with a purity higher than 99.9%.
- Typical projects
30,000 tons/year crude dimethyl carbonate (DMC) refining case
Processing capacity: 33251 tons/year
Operating time: 7200 hours/year
Operation flexibility: 60-120%
Raw material specifications:
| serial number | Components | unit | content |
| 1 | Dimethyl carbonate | %wt | 57.56 |
| 2 | Methanol | %wt | 37.35 |
| 3 | dimethyl oxalate | %wt | 5.34 |
| 4 | Paraformaldehyde | %wt | 1.91 |
| 5 | Methyl formate | %wt | 1.2 |
| 6 | dimethoxymethane | %wt | 1.2 |
| 7 | formaldehyde | %wt | 0.91 |
| 8 | water | %wt | 0.43 |
| 9 | Tetrahydrofuran-2-methanol | %wt | 0.08 |
| 10 | Acetoxyacetic acid | %wt | 0.03 |
Product specifications:
| serial number | product | Specification | unit | Capacity |
| 1 | Dimethyl carbonate | 99.9% | t/a | 13009 |
| 2 | Methyl | 92%wt | t/a | 2187 |
| 3 | Methanol | 95% wt | t/a | 9385 |
Project pictures:
For more detailed technical information on dimethyl carbonate, please contact us. Hubei Sanli Liquidambar Technology Co., Ltd. specializes in providing dimethyl carbonate process technology.