Terephthalic acid

Terephthalic Acid Copolyesters Containing Tetramethylcyclobutanediol for High-Performance Plastics

There is a need for high-performance applications for terephthalic acid (TPA) polyesters with high heat resistance, impact toughness, and optical clarity. Bisphenol A (BPA) based polycarbonates and polyarylates have such properties, but BPA is an endocrine disruptor. Therefore, new TPA polyesters that are less hazardous to health and the environment are becoming popular. Tetramethylcyclobutanediol (TMCD) is a difunctional monomer that can be polymerized with TPA and other diols to yield copolyesters with superior properties to conventional TPA polyesters. It has a cyclobutyl ring that makes it more rigid than cyclohexanedimethanol (CHDM) and EG. Thus, TMCD containing TPA copolyesters can have high heat resistance and impact strength. TPA can be made from abundantly available upcycled polyethylene terephthalate (PET). Therefore, this review discusses the synthesis of monomers and copolyesters, the impact of diol composition on material properties, molecular weight, effects of photodegradation, health safety, and substitution of cyclobutane diols for future polyesters.

A bacterium that degrades and assimilates poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) is used extensively worldwide in plastic products, and its accumulation in the environment has become a global concern. Because the ability to enzymatically degrade PET has been thought to be limited to a few fungal species, biodegradation is not yet a viable remediation or recycling strategy. By screening natural microbial communities exposed to PET in the environment, we isolated a novel bacterium, Ideonella sakaiensis 201-F6, that is able to use PET as its major energy and carbon source. When grown on PET, this strain produces two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. Both enzymes are required to enzymatically convert PET efficiently into its two environmentally benign monomers, terephthalic acid and ethylene glycol.

Cytotoxic benzylidene hydrazides of terephthalic acid and related compounds

The present investigation involved the synthesis of a number of novel benzylidene hydrazides as candidate cytotoxic agents. The preparation of these compounds from terephthalic acid and isophthalic acid proceeded satisfactorily. However, the reaction of phthalic acid hydrazide with various aryl aldehydes was unsuccessful in general. Some of the unexpected products were identified. The shapes and also the distances between the centers of the aryl rings designated B and C of three representative compounds 1b, 2b and 3b were determined. The compounds designated 1a-e, 2a-e and 3b were screened against human HCT116 and HT29 colon cancer cells as well as human CRL1790 non-malignant colon cells which revealed the tumor-selective toxicity displayed by these compounds.

Cerium-terephthalic acid metal-organic frameworks for ratiometric fluorescence detecting and scavenging·OH from fuel combustion gas

Hydroxyl radical (?OH) in fuel combustion gas seriously damages human health. The techniques for simultaneously detecting and scavenging ?OH in these gases are limited by poor thermal resistance. To meet this challenge, herein, metal organic frameworks (MOFs) with high thermal stability (80-400 °C) and dual function (?OH detection and elimination) are developed by coordinating Ce ions with terephthalic acid (TA) (Ce-BDC). Due to the reversible conversion between Ce³⁺ and Ce⁴⁺, and the high concentration of Ce³⁺ on the surface of Ce-BDC MOFs (89.6%), an ?OH scavenging efficiency over 90% is realized. Ratiometric fluorescence (I_{440 nm}/I_{355 nm}) detection of ?OH with a low detection limit of ?4 μM is established by adopting Ce ions as an internal standard and TA as an ?OH-responsive fluorophore. For real applications, the Ce-BDC MOFs demonstrate excellent ?OH detection sensitivity and high ?OH scavenging efficiency in gas produced from cigarettes, wood fiber and machine oil. Mouse model results show that the damage caused by ?OH in cigarette smoke can be greatly reduced by Ce-BDC MOFs. This work provides a promising strategy for sensitively detecting and efficiently eliminating ?OH in fuel combustion gas.

Halogenated Terephthalic Acid "Antenna Effects" in Lanthanide-SURMOF Thin Films

Lanthanide-based crystalline coatings have a great potential for energy-conversion devices, but until now luminescent surface-anchored materials were difficult to fabricate. Thin films, called lanthanides surface-mounted metal-organic frameworks (SURMOFs) with tetrasubstituted halide (fluorine, chlorine, and bromine) terephthalic acid derivative linkers as a basic platform for optical devices, exhibit a high quantum yield of fluorescence visible to the naked eyes under ambient light. We show that we can tune the luminescent properties in thin films by halide substitution, which affords control over the molecular structure of the material. We rationalize the mechanism for the modulation of the photophysical properties by "antenna effect", which controls the energy transfer and quantum yields using experimental and theoretical techniques for chelated lanthanides as a function of the type of atom substitutions at the phenyl rings and the resulting dihedral angle between phenyl rings in the linkers and carboxylate groups.