Cyclic Taurine Production from Alkali Isethionate

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Solution Overview

Problem

The existing processes for producing taurine from ethylene oxide result in low overall yields and generate significant waste streams, particularly due to the ammonolysis of sodium isethionate and the separation of taurine from sodium sulfate, with yields not exceeding 80% and complex ion exchange resin regeneration requirements.

Innovation Solution

A cyclic process is developed to convert alkali ditaurinate and alkali tritaurinate byproducts into alkali taurinate, utilizing ammonolysis reactions under controlled conditions, and a method for separating sodium sulfate from taurine and other byproducts, allowing for continuous recycling and high yield production of taurine, exceeding 90%, by converting residual taurine into a highly soluble form for crystallization and recycling mother liquors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ammonolysis of sodium isethionate is performed to produce taurine, then taurine yield is improved, but byproducts (sodium ditaurinate and sodium tritaurinate) are generated reducing overall yield

Engineering Contradiction:

Improvetaurine production rateVSAvoidoverall yield of taurine

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent converts the harmful byproducts (sodium ditaurinate and sodium tritaurinate) into beneficial products by performing additional ammonolysis reactions. These byproducts are reacted with ammonia to produce more taurine, thereby converting waste material into valuable product and achieving overall yields greater than 90%.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Instead of discarding the byproducts from the first ammonolysis reaction, the patent recovers them by subjecting them to further ammonolysis treatment. The sodium ditaurinate and sodium tritaurinate are converted back into taurine through controlled heating with ammonia, thus recovering what would otherwise be lost material.

Inventive Principle:

Principle #34Discarding and recovering

2Manufacturing precision

If ion exchange resins are used to separate taurine from sodium sulfate, then separation efficiency is improved, but process complexity and regeneration requirements increase

Engineering Contradiction:

Improveseparation efficiency of taurineVSAvoidion exchange resin regeneration system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes sodium sulfate from the reaction mixture through filtration before the ammonolysis step. By eliminating sodium sulfate early in the process, the need for complex ion exchange resin systems is avoided, simplifying the overall process while maintaining effective separation of taurine.

Inventive Principle:

Principle #2Taking out (Extraction)

3Speed

If conventional ammonolysis conditions are used, then reaction speed is improved, but byproduct formation increases reducing yield

Engineering Contradiction:

Improveammonolysis reaction rateVSAvoidtaurine yield

Core Design Contradiction:

SpeedVSLoss of substance

Solution Approach 1:

The patent employs a multi-stage ammonolysis process with periodic treatment. The first ammonolysis reaction is followed by a second ammonolysis step that specifically targets the byproducts. This periodic application of ammonolysis conditions ensures complete conversion to taurine while maintaining efficient reaction rates through controlled heating at 180-270°C.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent optimizes reaction parameters including temperature (180-270°C), pressure (autogenous to 260 bars), and ammonia concentration (20-30% aqueous ammonia) to achieve the optimal balance between reaction speed and selectivity. These parameter changes enable fast reaction rates while minimizing unwanted byproduct formation through precise control of the ammonolysis conditions.

Inventive Principle:

Principle #35Parameter changes

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 a high overall yield of taurine greater than 90%, reduces waste generation, and facilitates the separation of sodium sulfate, enabling an economical and efficient production cycle with minimal waste, particularly applicable to ethylene oxide, ethanol, and ethylene processes.

Implementation Method 1

the ammonolysis of sodium isethionate to yield sodium taurinate

Methodology Applied

Scientific EffectAmmonolysis: Chemical Bonding

Implementation Method 2

heating an aqueous solution of sodium taurinate at a temperature of 210° C.

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

Crude taurine is easily obtained by filtration from a crystalline suspension of taurine after cooling

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUSRE48392E1Cyclic process for the production of taurine from alkali isethionate

Publication Date: 2021.01.12 LIBRE HLDG

AI summary

A cyclic process is disclosed for the production of taurine from alkali isethionate in a high overall yield by continuously converting the byproducts of the ammonolysis reaction, sodium ditaurinate and sodium tritaurinate, to sodium taurinate. Sodium sulfate and residual taurine in the crystallization mother liquor are efficiently separated by converting taurine into a highly soluble form of sodium taurinate or ammonium taurinate while selectively crystallizing sodium sulfate.