Comparison between titanium tetrabutoxide and a new commercial titanium dioxide based catalyst used for the synthesis of poly(ethylene terephthalate)

Abstract

Titanium-based catalysts for poly(alkylene terephthalate) synthesis have been known for many years. Up to now, organotitanate compounds are used as catalysts on an industrial scale only for the synthesis of poly(butylene terephthalate) (PBT), poly(trimethylene terephthalate) (PTT), and related copolyesters; for poly(ethylene terephthalate) (PET), synthesis antimony-based catalysts are preferred. In fact, in this case, titanium is known to cause undesirable discoloration. In this article, a study of PET synthesis using different concentrations of a new titanium dioxide based catalyst (C-94), commercially available from Acordis Industrial Fibers GmbH, is carried out and compared with the results obtained with titanium tetrabutoxide (TBT) catalyst in the same experimental conditions. The solid-state properties and composition of C-94 was investigated by thermogravimetric analysis (TGA) coupled with mass spectroscopy and by X-ray powder diffraction (XRD). A characterization of the polymers prepared with C-94 and TBT is also described. The results have shown that the use of C-94 leads to more hydrolytically stable polymers, whereas no evidence of difference in the catalytic activity, carboxyl end-groups concentration, diethylene glycol content, and thermal properties were revealed.

Synthesis and properties of polyesters derived from renewable eugenol and α,ω-diols via a continuous overheating method

“…46 In consequence, excessively low temperature was unfavourable to the transesterification reactions. In order to reduce the volatilization of α,ω-diols as much as possible and advocate the strategy of sustainable development, a continuous overheating method was adopted across the transesterification stage.…”

The chemistry, manufacture and tensile behaviour of polyester fibers

“…Either TiO 2 or a mixture with SiO 2 or TiO 2 /ZrO 2 compositions can be used as polymerization catalysts (AKZO patent) as well [19]. The discoloration, occurring when titanium alkoxides are employed, is usually attributed to organic contaminants formed during the polymerization process [20]. It was found that the C-94 catalyst (TiO 2 and SiO 2 with a ratio of 9:1 w/w) [20] is six to eight times as active as antimony oxide catalyst [21].…”

Poli(tereftalato de etileno), PET: uma revisão sobre os processos de síntese, mecanismos de degradação e sua reciclagem

“…Em alguns produtos finais de embalagens de alimentos ou bebidas carbonatadas, foram encontrados resíduos a base de antimônio, colocando em risco a saúde pública. Devido à demanda de aumento de produção e que cumpra as regulamentações alimentícias exigidas, são crescentes as pesquisas em busca de catalisadores alternativos para a produção de PET [37][38][39] . Os catalisadores a base de titânio apresentam atividade superior aos convencionalmente utilizados.…”

“…Entretanto, com o desenvolvimento de novos sistemas catalíticos a base de titânio tais como tetrabutóxido de titânio (Ti (OC 4 H 9 ) 4 ), C 94 (mistura de TiO 2 /SiO 2 , a uma razão de 9/1 wt. %) e complexos de Ti-P, várias propriedades do produto final foram otimizadas, como: transparên-cia, taxa reacional, aumento da atividade catalítica, melhor coloração e, principalmente, uma redução na quantidade de catalisador necessária (de 250-300 µg.kg -1 para catalisadores a base de antimônio para 10-30 µg.kg -1 em catalisadores a base de titânio) [36,37,39,40] .…”