Cyclohexanedimethanol
Encyclopedia
Cyclohexanedimethanol is an organic compound
with formula C6H10(CH2OH)2. It is a colorless low-melting solid used in the production of polyester
resins. Commercial samples consist of a mixture of cis and trans isomers, as seen for other disubstituted derivatives of cyclohexane
.
of dimethyl terephthalate
(DMT). The reaction conducted in two steps beginning with the conversion of DMT to the diester dimethyl 1,4-cyclohexanedicarboxylate (DMCD). In the second step DMCD is further hydrogenated to CHDM. The cis/trans ratio of CHDM is differ according to the catalyst, 80:20 for Cu4Ru12 catalyst, 65:35 in case of the RuPt catalyst, 88:12 for the Ru-Sn catalyst
, 30:70 in case of the copper chromite catalyst usually used in industrial processing.
Most of the commercial CHDM has cis/trans ratio of 30:70. The leading producers in CHDM are Eastman Chemicals and SK Chemicals.
(PET), or polyethylene terephalic ester (PETE), from which plastic bottles are made.
Thermoplastic polyesters containing CHDM exhibit enhanced strength, clarity, and solvent resistance. The exact properties of the polyesters vary from the high melting crystalline poly(1,4-cyclohexylenedimethylene terephthalate), PCT, to the non-crystalline copolyesters with the combination of ethylene glycol
and CHDM in the backbone. The properties of these polyesters is also dependent on the cis/trans ratio of the CHDM monomer. CHDM has low melting point and reduce the degree of crystallinity of PET homopolymer. These PET is known as glycol modified polyethylene terephthalate, PETG. PETG is used in many fields, electronics, automobiles, barrier, and medicals etc. So the resin can be plastically formed with lower force and /or with low heat requirement. These reasons stabilize the polymer from degradation and reduce final products acetaldehyde
level to acceptable level.
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with formula C6H10(CH2OH)2. It is a colorless low-melting solid used in the production of polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
resins. Commercial samples consist of a mixture of cis and trans isomers, as seen for other disubstituted derivatives of cyclohexane
Cyclohexane
Cyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which being intermediates used in the production of nylon...
.
Production
CHDM is produced by catalytic hydrogenationHydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...
of dimethyl terephthalate
Dimethyl terephthalate
Dimethyl terephthalate is an organic compound with the formula C6H42. It is the diester formed from terephthalic acid and methanol. It is a white solid that melts to give a distillable colourless liquid.-Production:...
(DMT). The reaction conducted in two steps beginning with the conversion of DMT to the diester dimethyl 1,4-cyclohexanedicarboxylate (DMCD). In the second step DMCD is further hydrogenated to CHDM. The cis/trans ratio of CHDM is differ according to the catalyst, 80:20 for Cu4Ru12 catalyst, 65:35 in case of the RuPt catalyst, 88:12 for the Ru-Sn catalyst
, 30:70 in case of the copper chromite catalyst usually used in industrial processing.
- C6H4(CO2CH3)2 + 3 H2 → C6H10(CO2CH3)2
- C6H10(CO2CH3)2 + 4 H2 → C6H10(CH2OH)2 + 2 CH3OH
Most of the commercial CHDM has cis/trans ratio of 30:70. The leading producers in CHDM are Eastman Chemicals and SK Chemicals.
Applications
Via the process called polycondensation, CHDM is a precursor to polyesters. It is one of the most important co-monomers for production of polyethylene terephthalatePolyethylene terephthalate
Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...
(PET), or polyethylene terephalic ester (PETE), from which plastic bottles are made.
Thermoplastic polyesters containing CHDM exhibit enhanced strength, clarity, and solvent resistance. The exact properties of the polyesters vary from the high melting crystalline poly(1,4-cyclohexylenedimethylene terephthalate), PCT, to the non-crystalline copolyesters with the combination of ethylene glycol
Ethylene glycol
Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
and CHDM in the backbone. The properties of these polyesters is also dependent on the cis/trans ratio of the CHDM monomer. CHDM has low melting point and reduce the degree of crystallinity of PET homopolymer. These PET is known as glycol modified polyethylene terephthalate, PETG. PETG is used in many fields, electronics, automobiles, barrier, and medicals etc. So the resin can be plastically formed with lower force and /or with low heat requirement. These reasons stabilize the polymer from degradation and reduce final products acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...
level to acceptable level.