Process for the Preparation of Oligo- and Polysiloxanes

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This invention describes a new method for producing oligo- and polysiloxanes (key components in silicone oils, rubbers, and resins) as well as N-substituted urea derivatives. The process involves reacting carbon dioxide (CO2) with aminosilane compounds to form silyl carbamates, which are then thermally decomposed to yield the desired siloxanes and urea derivatives, without generating corrosive or hazardous chlorinated by-products.

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• Hydrophobization (waterproofing) of glass, ceramics, textiles, and leather
• Lubricants for plastics processing and plastic gearing
• Additives in polishes and printing inks
• Manometer and hydraulic fluids
• Release agents in manufacturing
• Defoamers and antifoaming agents in industrial processes
• Collectors in mineral flotation processes
• Pharmaceutical intermediates (urea derivatives)
• Flame retardants (urea derivatives) for plastics and textiles
• Organic synthesis building blocks for advanced chemicals

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• Greener, safer process avoiding toxic and corrosive by-products like hydrochloric acid
• Eliminates need for highly water-sensitive starting materials (chlorosilanes)
• Can be conducted under milder conditions and even in the presence of small amounts of water
• Enables efficient and flexible production of both linear and branched/crosslinked siloxanes
• Allows the synthesis of both symmetrical and unsymmetrical urea derivatives, including those difficult to access by other means
• Process is robust, scalable, and suitable for industrial manufacturing
• CO2 utilization contributes to sustainability and resource efficiency
• No requirement for expensive catalysts or highly toxic reagents like phosgene

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Inventors & Applicants

Patent Abstract

The invention relates to a method for producing oligo- or polysiloxanes, which are widely used as silicone oils, silicone rubbers (elastomers), and silicone resins, and for producing N-substituted urea derivatives. The oligo- or polysiloxanes produced according to the invention are suitable for, inter alia, hydrophobing glass, ceramic, textiles, or leather, and as lubricants for plastics processing, lubricants in plastic gearing, polishing agent additives, for preventing pigments from floating in pigmented coatings, as manometer fluid, collectors in flotation processes and for use in defoamer formulas, hydraulic fluids, release agents, printing ink, or metal cleaning agents. The N-substituted urea derivatives produced according to the invention are suitable for use as flame retardants, in pharmaceuticals, but also in organic synthesis. The method according to the invention for producing oligo- and/or polysiloxanes and/or N-substituted urea derivatives is based on inserting CO2 into an aminosilane, which has at least 2 amino groups, in order to form silyl carbamate. Subsequently, the obtained silyl carbamate is pyrolyzed to form oligo- or polysiloxane, carbon dioxide, and N-substituted urea.