Terephthalate Ester Production via C6-C13 Alcohol Esterification
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Solution Overview
Problem
There is a need for alternative plasticizers that are not subject to the same classification and restrictions as low molecular weight phthalates, particularly for applications like medical and food contact, which should be produced from readily available materials and offer comparable performance properties.
Innovation Solution
The method involves esterifying C6-C13 alcohols with dimethyl terephthalate in the presence of a catalyst to produce terephthalate esters, with the ester and alcohol recovered through fractionation and partial condensation of methanol, using solvents like methanol and dioxane, and catalysts such as titanate and sulfuric acid, to achieve efficient production of terephthalate esters like di-2-ethylhexyl terephthalate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low molecular weight phthalate esters are used as plasticizers, then good performance properties are achieved, but they are subject to classification and restrictions under REACH and cannot be produced or used in Europe after February 2015
Solution Approach 1:
The patent changes the chemical structure parameters by using terephthalic acid instead of phthalic acid, and employing high molecular weight alcohols (C6-C13) to create terephthalate esters with different molecular weights and properties. This structural parameter change produces plasticizers that are not subject to REACH restrictions while maintaining comparable performance characteristics.
Solution Approach 2:
The patent creates composite plasticizer structures by combining terephthalic acid with various high molecular weight alcohols (2-ethylhexanol, isononyl alcohol, isodecyl alcohol, etc.), producing a family of ester compounds with diverse properties. These composite structures provide alternatives to restricted phthalates while maintaining plasticizer functionality.
2Object-affected harmful factors
If alternative plasticizers are developed to replace restricted phthalates, then compliance with REACH is achieved, but new production processes and materials must be developed
Solution Approach 1:
The patent employs a universal esterification process that can produce multiple different terephthalate esters by simply changing the alcohol component while using the same core materials (terephthalic acid or its derivatives). This multi-functional process approach allows compliance with REACH while maintaining ease of manufacture through a standardized production methodology.
Solution Approach 2:
The patent utilizes parameter changes in the esterification process, particularly in temperature, pressure, and catalyst selection, to optimize the production of terephthalate esters. By adjusting these parameters, the process achieves high conversion rates and product quality while maintaining operational simplicity and manufacturing ease.
3Reliability
If esterification of terephthalic acid with high molecular weight alcohols is performed, then restricted phthalate alternatives are produced, but the process requires specific conditions (temperature, pressure, catalysts)
Solution Approach 1:
The patent optimizes process parameters including temperature (150-250°C), pressure (1-10 bar), and catalyst concentration (0.01-1%) to achieve efficient esterification. By carefully controlling these parameters, the process produces high-quality alternative plasticizers while managing device complexity through standardized condition ranges.
Solution Approach 2:
The patent employs catalysts (such as sulfuric acid, p-toluenesulfonic acid, or metal oxides) as intermediaries to facilitate the esterification reaction between terephthalic acid and high molecular weight alcohols. These catalysts enable the reaction to proceed under milder conditions and with higher efficiency, reducing the overall complexity of process control.
4Productivity
If methanol is used as a solvent in the esterification process, then reaction efficiency is improved, but methanol must be recovered through fractionation and partial condensation
Solution Approach 1:
The patent implements a methanol recovery system that separates and recovers methanol from the reaction mixture through fractionation and partial condensation. By recovering methanol for reuse or disposal, the process maintains high productivity and reaction efficiency while managing the complexity of the recovery system through targeted separation techniques.
Solution Approach 2:
The patent utilizes phase transitions (vaporization and condensation) of methanol to enable its separation from the reaction mixture. By controlling temperature and pressure to exploit the different volatility characteristics of methanol and other components, the system efficiently recovers methanol while maintaining overall process productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a viable alternative to restricted phthalate esters by producing terephthalate esters with comparable performance properties, utilizing readily available materials and improved production processes, thus addressing the need for restricted applications like medical and food contact uses.
Implementation Method 1
esterifying C6-C13 alcohols with dimethyl terephthalate in the presence of a catalyst to produce terephthalate esters
Implementation Method 2
in the presence of a catalyst to produce the terephthalate ester and methanol
Implementation Method 3
the terephthalate ester is recovered by fractionation
Implementation Method 4
at least a portion of the C6-C13 alcohol is recovered by fractionation and the partial condensation of the methanol
Data Source
AI summary
Embodiments of an invention disclosed herein relate to methods to produce terephthalate esters, the methods include esterifying at least one C6-C13 alcohol with dimethyl terephthalate (DMT) in the presence of a catalyst to produce the terephthalate esters.