Simultaneous Isobutanol Dehydration and Skeletal Isomerization
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Solution Overview
Problem
Current processes for producing isobutene and n-butenes from isobutanol involve separate dehydration and skeletal isomerization steps, which are inefficient and often result in low selectivity for the desired products due to secondary reactions and the need for fossil-based resources.
Innovation Solution
A process for simultaneous dehydration and skeletal isomerization of isobutanol using crystalline silicates with high Si/Al ratios, molecular sieves, or modified alumina catalysts at controlled temperatures and space velocities, producing a mixture of n-butenes and iso-butene with high yield and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate dehydration and skeletal isomerization steps are used, then the process can be carried out with conventional catalysts, but the selectivity for desired products is low due to secondary reactions
Solution Approach 1:
The patent combines two separate reaction steps (dehydration and skeletal isomerization) into a single simultaneous reaction step by using a bifunctional catalyst that possesses both dehydration function and skeletal isomerization function. This merging of functions eliminates the need for separate reaction steps and intermediate product handling, thereby improving selectivity by preventing secondary reactions that occur during sequential processing.
Solution Approach 2:
The patent employs a bifunctional catalyst that performs multiple functions simultaneously: it acts as both a dehydration catalyst and a skeletal isomerization catalyst. This multi-functionality allows the single catalyst to drive both chemical transformations required to convert isobutanol into n-butenes and iso-butene, improving process efficiency and product selectivity.
2Productivity
If conventional catalysts are used for dehydration, then the process is simple, but skeletal isomerization does not occur efficiently
Solution Approach 1:
The patent uses a composite catalyst system that combines different functional components: one component provides dehydration activity while another component provides skeletal isomerization activity. This composite structure allows the catalyst to perform both required transformations efficiently, achieving high productivity for n-butenes and iso-butene production.
Solution Approach 2:
The patent modifies catalyst properties (such as acidity, pore structure, or metal loading) to optimize both dehydration and skeletal isomerization activities. By adjusting these parameters, the catalyst achieves the dual functionality needed to convert isobutanol to the desired butene products with high yield.
3Productivity
If multiple reaction steps are used, then each reaction can be optimized separately, but the overall process efficiency is reduced
Solution Approach 1:
The patent merges the dehydration and skeletal isomerization reactions into a single simultaneous process, eliminating the time required for sequential processing and intermediate handling. This time-saving approach improves overall process efficiency while maintaining high product yield through the bifunctional catalyst.
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 process achieves high isobutanol conversion and selectivity for n-butenes and iso-butene, resembling thermodynamic equilibrium compositions, allowing for the replacement of fossil-based raffinate I in petrochemical plants and enabling production from renewable resources.
Implementation Method 1
contacting said stream with a catalyst in said reactor at conditions effective to dehydrate and skeletal isomerise at least a portion of the isobutanol to make a mixture of n-butenes and iso-butene
Implementation Method 2
contacting said stream with a catalyst in said reactor at conditions effective to dehydrate and skeletal isomerise at least a portion of the isobutanol to make a mixture of n-butenes and iso-butene
Data Source
Figure 1
AI summary
The present invention (in a first embodiment) relates to a process for the simu ltaneou s dehyd ration and skeletal isomerisation of isobuta nol to ma ke substantially corresponding olefins, having the same number of carbons and consisting essentially of a mixture of n-butenes and iso-butene, said process comprising: a) introducing in a reactor a stream (A) comprising isobutanol, optionally water, optionally an inert component, b) contacting said stream with a catalyst in said reactor at conditions effective to dehydrate and skeletal isomerise at least a portion of the isobutanol to make a mixture of n-butenes and iso-butene, c) recovering from said reactor a stream (B), removing water, the inert component if any and unconverted isobutanol if any to get a mixture of n-butenes and iso-butene, Wherein, the WHSV of the isobutanol is at least 1 h-1 or the temperature is from 200°C to 600°C and the catalyst is capable to make simultaneously the dehydration and skeletal isomerization of butene. The catalyst is a crystalline silicate of the group FER, MWW, EUO, MFS, ZSM-48, MTT, MFI, MEL or TON having Si/AI higher than 10, or a dealuminated crystalline silicate of the group FER, MWW, EUO, MFS, ZSM- 48, MTT, MFI, MEL or TON having Si/AI higher than 10, or a phosphorus modified crystalline silicate of the group FER, MWW, EUO, MFS, ZSM-48, MTT, MFI, MEL or TON having Si/AI higher than 10, or a silicoaluminaphosphate molecular sieve of the group AEL, or a silicated, zirconated or titanated or fluorinated alumina. Advantageously the stream (B) is fractionated in a step d) to produce a n-butenes stream (N) and to remove the essential part of isobutene optionally recycled with stream (A) to the dehydration/isomerization reactor of step b).