Stabilizing Ester Viscosity via Ethene Co-oligomerization
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Solution Overview
Problem
The challenge lies in maintaining a constant viscosity of ester mixtures used as plasticizers for PVC, particularly when the composition of n-butene sources fluctuates, making it difficult to ensure consistent plasticizer quality due to changes in the availability and quality of raw materials.
Innovation Solution
Incorporating ethene into the production process by either adding ethene oligomers to butene oligomers or co-oligomerizing ethene with butene, allowing for the adjustment of viscosity through controlled addition of ethene, thereby stabilizing the viscosity of the ester mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If n-butene from fluctuating sources is used as raw material, then productivity is improved by utilizing available C4 sources, but manufacturing precision deteriorates due to variable viscosity of the ester mixture
Solution Approach 1:
C2-olefins (ethene) are introduced as an intermediary substance to mediate between the variable n-butene feedstock and the desired constant viscosity product. The C2-olefins mix with C4-olefins in the oligomerization process to produce C8-olefins with controlled branching, thereby buffering the effect of feedstock variations on final product viscosity.
Solution Approach 2:
The composition parameters of the feed mixture are dynamically adjusted by varying the proportion of C2-olefins added to the n-butene stream. When viscosity deviates from target values, the C2-olefin content is modified to shift the branching degree of C8-olefins, thereby restoring viscosity to specification.
2Adaptability or versatility
If the composition of n-butene changes over time, then adaptability is improved by using alternative C4 sources, but stability of the object's composition deteriorates as viscosity becomes unpredictable
Solution Approach 1:
C2-olefins serve as a stabilizing intermediary that decouples the relationship between variable n-butene composition and final ester viscosity. By introducing this additional controllable variable, the system can adapt to different n-butene sources while maintaining stable product composition through active composition management.
Solution Approach 2:
A feedback control system continuously monitors the viscosity or composition of the ester mixture and adjusts the C2-olefin addition rate accordingly. When viscosity drifts from target values due to n-butene composition changes, the control system modifies the C2-olefin feed to compensate and restore viscosity stability.
3Ease of manufacture
If branching of C8 olefins is increased, then ease of manufacture is improved by using conventional n-butene oligomerization, but viscosity of the ester mixture increases beyond desired levels
Solution Approach 1:
The branching parameter of C8-olefins is adjusted by changing the feed composition ratio of C2- to C4-olefins. Lower C2-olefin proportions produce more branched C8-olefins (higher viscosity), while higher C2-olefin proportions produce less branched C8-olefins (lower viscosity), allowing viscosity control while maintaining the simplicity of catalytic oligomerization.
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 enables the production of ester mixtures with a stable viscosity over time, even with fluctuating raw material qualities, by minimizing the branching of C8 olefins and thus reducing the viscosity of the final ester mixture.
Implementation Method 1
a first oligomerization is subjected to obtain an oligomer. At least some of the butene oligomers contained in the oligomer are subjected to a hydroformylation
Implementation Method 2
at least some of the butene oligomers contained in the oligomer are subjected to a hydroformylation Aldehydes are oxidized
Implementation Method 3
at least some of which are hydrogenated by subsequent hydrogenation into an alcohol mixture
Implementation Method 4
which is then converted into the ester mixture
Data Source
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AI summary
The invention relates to a process for producing an ester mixture in which a feed mixture containing n-butene, the composition of which changes over time, is first oligomerized and then converted into an ester mixture by hydroformylation, hydrogenation, and esterification. An approximation of the actual viscosity of the ester mixture is determined in this process. The objective is to provide a comparatively simple process that makes it possible to convert n-butene with a time-varying composition into an ester mixture whose viscosity can be kept largely constant over a long period, even when using a discontinuous C4 source that yields fluctuating qualities over this period. This is achieved through the targeted use of a second raw material, namely ethene.It has been found that the viscosity of n-butene-based ester mixtures can be influenced by the targeted use of ethene in the preparation of the ester precursors. Specifically, the invention proposes two methods for using ethene: firstly, directly as a C2 olefin, and secondly, as a C8 olefin after prior separate oligomerization.