| 词条 | 2,6-Dimethylnaphthalene |
| 释义 |
| ImageFile = 2,6-dimethylnaphthalene.svg | ImageSize = 200px | IUPACName = 2,6-Dimethylnaphthalene | OtherNames = |Section1={{Chembox Identifiers | CASNo = 581-42-0 | PubChem = 11387 | ChemSpiderID = 10909 | ChEBI = 34251 | SMILES = Cc1ccc2cc(ccc2c1)C | InChI = 1/C12H12/c1-9-3-5-12-8-10(2)4-6-11(12)7-9/h3-8H,1-2H3 | InChIKey = YGYNBBAUIYTWBF-UHFFFAOYAZ | StdInChI = 1S/C12H12/c1-9-3-5-12-8-10(2)4-6-11(12)7-9/h3-8H,1-2H3 | StdInChIKey = YGYNBBAUIYTWBF-UHFFFAOYSA-N }} |Section2={{Chembox Properties | C=12 | H=12 | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = }} |Section3={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}2,6-Dimethylnaphthalene (2,6-DMN) is a polycyclic aromatic hydrocarbon. It is one of the ten dimethylnaphthalene isomers, which are derived from naphthalene by the addition of two methyl groups. 2,6-DMN is of commercial importance as a starting material for high-performance polyester fibers and films. Polyethylene naphthalate (PEN) is made from the product of oxidation 2,6-DMN.[1] SynthesisAlkylated naphthalenes (methyl-, dimethyl-, and poly-methyl naphthalenes, thus including 2,6-DMN) are found in low concentrations in crude oil and coal tar. Separation is difficult, expensive, and requires a number of operations such as selective crystallization and adsorption, in addition to any isomerization reactions.[2] There has been a search for suitable synthetic routes to 2,6-DMN. In the "alkenylation process" butadiene (1) , o-xylene (2), and Sodium-potassium alloy (3) are used, which react to form 5-(orthotolyl)pent-2-ene (OTP, 3).[3] OTP is subsequently cyclized to 1,5-dimethyltetraline (4). Dehydrogenation then provides 1,5-dimethylnaphthalene (1,5-DMN, 5). Finally, 1,5-DMN is isomerized to 2,6-DMN (6). In the final step, other mono-, di-, and tri-methylnaphthalenes are formed. More work is therefore required in separation of the mixture, which is done by selective crystallization. {{Clear left}} Applications2,6-Dimethylnaphthalene is mainly used for the preparation of 2,6-naphthalenedicarboxylic acid by oxidation of 2,6-dimethylnaphthalene in the liquid phase. 2,6-Naphthalenedicarboxylic acid is a monomer for the production of high-performance polymers, in particular poly (ethylene-2,6-naphthalene dicarboxylate) or shorter polyethylene naphthalate (PEN), a polyester which is stronger and has a higher thermal resistance than the frequently used polyethylene terephthalate (PET). However, 2,6-DMN is a more expensive intermediate than terephthalic acid that is used for PET. References1. ^{{cite journal|doi=10.1016/S0926-860X(01)00809-2|title=Production of Dimethyl-2,6-Naphthalenedicarboxylate: Precursor to Polyethylene Naphthalate|author=Lillwitz, L. D.|journal=Applied Catalysis, A: General |year=2001|volume=221|pages==337-358}} {{DEFAULTSORT:Dimethylnaphthalene, 2,6-}}2. ^{{US patent reference |number= 5004853 |issue-date = April 2, 1991 |inventor= Paul T. Barger, Timothy J. Barder, David Y. Lin, Simon H. Hobbs |title= Continuous process for the production of 2,6-dimethylnaphthalene}} 3. ^{{US patent reference |issue-date = March 30, 1993 |inventor= Lawrence D. Lillwitz, Anne M. Karachewski |title= Alkylation of alkylaromatics promoted by sonicated alkali metal}} 2 : Polycyclic aromatic hydrocarbons|Naphthalenes |
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