Low-sulfur polysulfide silanes and process for preparation

A low-sulfide and polysulfide technology, applied in the field of removal steps, can solve the problems of reducing advantages, polluting final products, and expensive trivalent phosphorus compounds

Inactive Publication Date: 2003-06-18
GENERAL ELECTRIC CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The second disadvantage is that with an average sulfur rating of 2, some individual low sulfide silane species must have a sulfur rating greater than 2, which further detracts from the advantages gained by...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Example 1 3-Triethoxysilyl-1-propyl subsulfide mixture with an average sulfur rating of 3.0 preparation

[0047] A reactor consisting of a 5 liter flask was suitable for reflux. Heat was supplied to the flask. The system was kept under nitrogen atmosphere. The bulk solid was removed from the reaction product by decanting. The solids were more completely removed by filter press. Press filtration was accomplished in a closed teflon-coated stainless steel vessel fitted with a filter plate. The solvent was removed from the product by distillation under reduced pressure using a rotary evaporator.

[0048] From 3-chloro-1-propyltriethoxysilane, anhydrous sodium sulfide, and sulfur in ethanol, prepare sulfur grades 2, 3, 4, 5, 6, and The 3-triethoxysilyl-1-propyl subsulfide mixture of 7. The product thus obtained was measured for its sulfur grade distribution by SFC (Supercritical Flow Chromatography) using a carbon dioxide mobile phase. The sulfur grade distribution...

Embodiment 2

[0050] Example 2 Preparation of High Purity 3-Triethoxysilyl-1-Propyl Disulfide

[0051] This example and the following two examples illustrate how disulfide silanes can be produced thereby suppressing thioethers by initially preparing a sulfur-rich low-sulfide silane mixture and thus containing S3, S4 (i.e. trisulfide, tetrasulfide) sulfide), and optionally higher sulfur grades, and then desulfurize the higher sulfur grades by the process of the present invention to convert the higher grades back to S2. The initial use of excess sulfur inhibits thioether formation which, once formed, cannot be easily converted to any other sulfur grade. Conversely, higher sulfur grades can be easily converted to S2 by the process of the present invention.

[0052] The reactor system is the same as above. From 3-chloro-1-propyltriethoxysilane, anhydrous sodium sulfide, and sulfur in ethanol, according to methods well known in the art, prepare 3- Triethoxysilyl-1-propyl subsulfide mixture....

Embodiment 3

[0053] Example 3 3-Triethoxysilyl-1-propyl low sulfide blend with low polysulfide sulfur content preparation

[0054] This example and the following two examples illustrate how complete or partial desulfurization of low sulfide silane compositions can be employed using alkoxy exchange coupling on silicon. During the desulfurization process described in the examples, ethoxysilane esters contaminated with methoxy esters were transesterified with ethanol to convert all methoxy esters to ethoxy esters.

[0055] A reactor consisting of a 5 liter flask was fitted to a 25-plate Oldershaw distillation column (28 mm ID). The top of the column is fitted with a distillation head capable of delivering variable and controllable reflux ratios. Provide heat to the flask. The system was kept under nitrogen atmosphere. The bulk solid was removed from the reaction product by decanting. Solids were more completely removed by gravity filtration through a sintered frit filter plate in the ...

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PUM

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Abstract

An improvement on existing methods to desulfurize oligosulfide silanes generates no added raw materials or waste streams in addition to the sodium chloride which is generated as a byproduct in the current manufacturing process for polysulfide silanes. This is accomplished by using mercaptosilane salts as desulfurizing agents, which yield more product in addition to that already obtained from the desulfurized silane of higher sulfur rank. The process simply entails reacting an oligosulfide silane with a mercaptosilane salt to thereby obtain an oligosulfide silane whose average sulfur rank is less than the starting oligosulfide silane. Coproduct sulfide salts can be recycled back to the oligosulfide manufacturing process. The mercaptosilane salts are novel materials as well.

Description

Background of the invention [0001] The present invention relates to a process for the preparation of polysulfide-functional silanes consisting of a novel sulfur rank distribution, ie a distribution which does not result from the practiced prior art. [0002] Sulfur-containing silane coupling agents are particularly useful in providing rubber tires, including automotive tires, with improved properties, generally by coupling inorganic fillers or fibers to the rubber matrix in a manner that results in improved properties. Sulfur-containing silane coupling agents that have achieved commercial success to date have been produced by unfavorable processes that include large amounts of chlorine-containing by-products. [0003] Many variations have been proposed for the preparation of oligosulfide-functional silanes starting from chloroalkylsilane starting materials and including sulfur and / or sulfur anions. This technique is described in the following US patents: US3,842,111, US3,873,...

Claims

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Application Information

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IPC IPC(8): C07F7/18
CPCC07F7/1836C07F7/1892C07F7/1804C07F7/18
Inventor R·W·克鲁斯
Owner GENERAL ELECTRIC CO
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