Dimethyl terephthalate
| 원료 | Methanol; p-Xylene | ||||||||||||
| 생산물 | dimethyl terephthalate | ||||||||||||
| 적용 | To produce fiver grade dimethyl terephthalate (DMT) from p-xylene and methanol. | ||||||||||||
| 설명 | Description: A mixture of p-xylene and p-methyl toluate is oxidized (2,3) with air in the presence of heavy metal catalysts to produce p-toluic acid and monomethyl terephthalate. These acids are then converted to p-methyl toluate and DMT. No reaction solvent is necessary during oxidation. The p-xylene and p-methyl toluate are subjected to continuous oxidation at 140 to 170℃ and 4 to 8 bar. The oxidate is esterified (4) at 250-280℃ and 20-25 bar. The overhead methanol from the esterifier is distilled (5) and recycled (6). The crude ester from the esterifier bottoms (4) is distilled in a column (9) where the overhead p-methyl toluate is recycled to the oxidizer and the bottom product is separated in a second column (10) into crude DMT overhead (11) and residue bottoms. Further purification is by crystallilzation (12) from methanol. DMT is separated from methanol in centrifuges (13) to fiber grade DMT (melting point of approximately 141℃). The filtrate is distilled (14) while the overhead methanol is recycled to the methanol tank (6). The isomers are purged (15) of recycle material. DMT in molten form (16) can be fed directly into polycondensation or transported in tankcars to the fiber plant. |
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| Properties in KDB |
Component Names and Formula
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