Preparation method and application of silicon-titanium composite homogeneous catalyst for polyester synthesis

Abstract

The invention relates to the field of polyester synthesis and discloses a preparation method and application of a silicon-titanium composite homogeneous catalyst for polyester synthesis. The preparation method comprises 1) dissolving a titanium compound and a silicon compound in a mixed solvent composed of ethylene glycol and another alcoholic solvent, adding a first co-catalyst and a second co-catalyst, and distilling under 80-120 DEG C and normal pressure; 2) adding a first complexing agent and a second complexing agent, and continuing to distill under 80-120 DEG C and normal pressure to obtain the silicon-titanium composite homogeneous catalyst. The preparation process of the catalyst herein involves a change to the titanium-silicon ratio and introduction of sulfonates, organic ligandsand phosphoric complexing agents; the introduction never affects the contents of titanium and silicon; the complexing agents can coordinate with titanium atoms, thereby changing an electronic environment of the titanium atoms, so that activity and stability of the catalyst are improved, selectivity is improved, the amount of side reactions is reduced effectively, and yellowing of polyester products is prevented.

Description

technical field [0001] The invention relates to the field of polyester synthesis, in particular to a preparation method and application of a silicon-titanium composite homogeneous catalyst for polyester synthesis. Background technique [0002] PET polyester, the full name of polyethylene terephthalate, is widely used in fibers, films, and packaging materials due to its good heat resistance, insulation, high resilience, and excellent acid and solvent resistance. , engineering plastics and many other fields, especially its washable, crisp, low price and other characteristics occupy the vast share of the chemical fiber market. The catalyst is an important part of polyester production. It not only affects the speed of esterification, transesterification and polycondensation reactions in the polyester production process, but also has a significant impact on side reactions, thermal stability and product color. [0003] At present, the most widely used polyester catalysts in indus...

AI Technical Summary

Problems solved by technology

Among them, the preparation technology of antimony-based catalysts is relatively mature, the production cost is low, the catalytic activity is moderate, the side reactions are few, and the hue is good. However, antimony is a heavy metal, which pollutes water and the environment, which is not conducive to green environmental protection and sustainable development.

Germanium-based catalysts have good catalytic activity, and the polyester obtained is pure white in color, does not contain heavy metals, and is basically pollution-free, but its resources are scarce and expensive, which limits its development

Therefore, the development of a catalyst that can replace the traditional antimony-based catalysts has become a trend in the development of polyester catalysts. The most important and promising one is a new catalyst with Ti as the main active component. This type of catalyst has high catalytic activity. less, meeting the requirements of non-toxic and environmental protection, but at this stage, titanium-based catalysts have many side reactions, yellow hue of polyester products, low stability of the catalyst itself, easy hydrolysis and other problems, so it has not been used on a large scale

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