1,4-Cyclohexanedimethanol on:
[Wikipedia]
[Google]
[Amazon]
Cyclohexanedimethanol (CHDM) is a mixture of
Thermoplastic polyesters containing CHDM exhibit enhanced strength, clarity, and solvent resistance. The properties of the polyesters vary from the high melting crystalline poly(1,4-cyclohexylenedimethylene terephthalate), PCT, to the non-crystalline copolyesters derived from both ethylene glycol and CHDM. The properties of these polyesters also is affected by the cis/trans ratio of the CHDM monomer. CHDM reduces the degree of crystallinity of PET homopolymer, improving its processability. The copolymer tends to resist degradation, e.g. to
U.S. National Library of Medicine: Hazardous Substances Databank – 1,4-cyclohexanedimethanol
Monomers Diols
isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers.
Iso ...
ic organic compounds with formula C6H10(CH2OH)2. It is a colorless low-melting solid used in the production of polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...
resins. Commercial samples consist of a mixture of cis and trans isomers. It is a di-substituted derivative of cyclohexane
Cyclohexane is a cycloalkane with the molecular formula . Cyclohexane is non-polar. Cyclohexane is a colorless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used). Cyclohexan ...
and is classified as a diol
A diol is a chemical compound containing two hydroxyl groups ( groups). An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified.
The most common industrial diol is e ...
, meaning that it has two OH functional groups. Commercial CHDM typically has a cis/trans ratio of 30:70.
Applications
Via the process called polycondensation, CHDM is a precursor to polyesters. It is one of the most important comonomers for production ofpolyethylene terephthalate
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods ...
(PET), or polyethylene terephthalic ester (PETE), from which plastic bottles are made.
Thermoplastic polyesters containing CHDM exhibit enhanced strength, clarity, and solvent resistance. The properties of the polyesters vary from the high melting crystalline poly(1,4-cyclohexylenedimethylene terephthalate), PCT, to the non-crystalline copolyesters derived from both ethylene glycol and CHDM. The properties of these polyesters also is affected by the cis/trans ratio of the CHDM monomer. CHDM reduces the degree of crystallinity of PET homopolymer, improving its processability. The copolymer tends to resist degradation, e.g. to acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the mos ...
. The copolymer with PET is known as glycol-modified polyethylene terephthalate, PETG. PETG is used in many fields, including electronics, automobiles, barrier, and medical, etc.
Production
CHDM is produced by catalytic hydrogenation of dimethyl terephthalate (DMT). The reaction conducted in two steps beginning with the conversion of DMT to the diester dimethyl 1,4-cyclohexanedicarboxylate (DMCD): :C6H4(CO2CH3)2 + 3 H2 → C6H10(CO2CH3)2 In the second step DMCD is further hydrogenated to CHDM: :C6H10(CO2CH3)2 + 4 H2 → C6H10(CH2OH)2 + 2 CH3OH A copper chromite catalyst is usually used industrially. The cis/trans ratio of the CHDM is affected by the catalyst. Byproduct of this process are 4-methylcyclohexanemethanol (CH3C6H10CH2OH) and the monoester methyl 4-methyl-4-cyclohexanecarboxylate (CH3C6H10CO2CH3,CAS registry number
A CAS Registry Number (also referred to as CAS RN or informally CAS Number) is a unique identification number assigned by the Chemical Abstracts Service (CAS), US to every chemical substance described in the open scientific literature. It inclu ...
51181-40-9).Peter Werle, Marcus Morawietz, Stefan Lundmark, Kent Sörensen, Esko Karvinen and Juha Lehtonen "Alcohols, Polyhydric" Ullmann's Encyclopedia of Industrial Chemistry, 2008, Wiley-VCH, Weinheim. The leading producers in CHDM are Eastman Chemical in US and SK Chemicals in South Korea.
References
{{ReflistExternal links
U.S. National Library of Medicine: Hazardous Substances Databank – 1,4-cyclohexanedimethanol
Monomers Diols