High Viscosity Group II Base Stock via Radical Coupling

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Solution Overview

Problem

Conventional methods for producing high viscosity lubricant base stocks, such as solvent processing and catalytic processing, face challenges in reducing sulfur and nitrogen content while maintaining viscosity, with catalytic processing limiting viscosities to around 10 cSt at 100°C and being costly for specialty polymeric materials.

Innovation Solution

A base stock composition is formed by radical coupling of a feedstock with a viscosity index of 50 to 120, using a peroxide catalyst to achieve a coupled effluent with a kinematic viscosity of at least 14 cSt, sulfur content of 0.03 wt% or less, and aromatics content of 10 wt% or less, followed by fractionation to achieve desired molecular weights and viscosities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If hydrotreating and hydrocracking processes are used for heteroatom removal, then sulfur and nitrogen content is reduced, but viscosity is significantly reduced

Engineering Contradiction:
Improvesulfur and nitrogen contentVSAvoidviscosity
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The patent applies preliminary heteroatom removal through hydroprocessing before the coupling reaction. By removing sulfur and nitrogen early in the process, the subsequent coupling reaction can build high molecular weight polymers without the viscosity-reducing side effects of heteroatoms, achieving both low heteroatom content and high viscosity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the molecular weight parameters through coupling reactions, combining lower molecular weight intermediates into higher molecular weight base stocks. This parameter change increases viscosity while the preliminary heteroatom removal ensures the final product maintains low sulfur and nitrogen content

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If catalytic processing is used for base stock production, then lower viscosity base stocks are produced, but the ability to make high viscosity base stocks is limited

Engineering Contradiction:
Improvebase stock productionVSAvoidviscosity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent merges catalytic processing with coupling reactions in a sequential process. The catalytic processing first creates clean, low-viscosity intermediates with removed heteroatoms, then coupling reactions merge these intermediates into high molecular weight polymers, combining the advantages of both methods to achieve high viscosity with low heteroatom content

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses parameter changes in molecular weight through controlled coupling reactions. By adjusting coupling conditions and feedstock selection, the process can produce base stocks across a wide viscosity range, overcoming the viscosity limitation of conventional catalytic processing

Inventive Principle:
Principle #35Parameter changes

3Temperature

If solvent processing is used for high viscosity base stock production, then high viscosity base stocks are produced, but heteroatom removal is less effective

Engineering Contradiction:
ImproveviscosityVSAvoidsulfur and nitrogen content
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary heteroatom removal through hydroprocessing before the coupling reaction. By removing sulfur and nitrogen early in the process, the subsequent coupling reaction can build high molecular weight polymers without the viscosity-reducing side effects of heteroatoms, achieving both low heteroatom content and high viscosity

Inventive Principle:
Principle #10Preliminary action

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

The method produces Group II base stocks with viscosities greater than conventional limits, retaining desirable properties of low molecular weight base stocks while increasing viscosity, and can be used to formulate high-quality lubricants with improved low-temperature performance and oxidation stability.

Implementation Method 1

A base stock composition is formed by radical coupling of a feedstock with a viscosity index of 50 to 120, using a peroxide catalyst to achieve a coupled effluent with a kinematic viscosity of at least 14 cSt

Methodology Applied
Scientific EffectRadical coupling:

Implementation Method 2

followed by fractionating the coupled effluent to achieve desired molecular weights and viscosities

Methodology Applied
Scientific EffectFractionation: Fractionation

Data Source

PatentEP3374474B1High viscosity base stock compositions
Publication Date: 2024.04.24 EXXONMOBIL TECHNOLOGY & ENGINEERING CO
  • EP3374474B1 patent drawingFigure 1~2
  • EP3374474B1 patent drawingFigure 3~4
  • EP3374474B1 patent drawingFigure 5~6

AI summary

Methods are provided for producing Group II base stocks having high viscosity and also having one or more properties indicative of a high quality base stock. The resulting Group II base stocks can have a viscosity at 100°C and/or a viscosity at 40°C that is greater than the corresponding viscosity for a conventional Group II base stock. Additionally, the resulting Group II base stocks can have one or more properties that are indicative of a high quality base stock.