WO2021180308A1 - Procédé de traitement de mélanges de (m/d/t)-méthylpolysiloxane à partir d'applications de transfert de chaleur - Google Patents

Procédé de traitement de mélanges de (m/d/t)-méthylpolysiloxane à partir d'applications de transfert de chaleur Download PDF

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Publication number
WO2021180308A1
WO2021180308A1 PCT/EP2020/056343 EP2020056343W WO2021180308A1 WO 2021180308 A1 WO2021180308 A1 WO 2021180308A1 EP 2020056343 W EP2020056343 W EP 2020056343W WO 2021180308 A1 WO2021180308 A1 WO 2021180308A1
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WO
WIPO (PCT)
Prior art keywords
boiler fraction
temperature range
units
range
mbar
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PCT/EP2020/056343
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German (de)
English (en)
Inventor
Maximilian MOXTER
Richard Weidner
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Wacker Chemie Ag
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Priority to CN202080078136.8A priority Critical patent/CN114729128B/zh
Priority to PCT/EP2020/056343 priority patent/WO2021180308A1/fr
Publication of WO2021180308A1 publication Critical patent/WO2021180308A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/32—Post-polymerisation treatment
    • C08G77/34—Purification
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • the present invention relates to a process for working up methylpolysiloxane mixtures containing (M / D / T) units with a content of T units in the range from 0.1 mol% to 30 mol%, which are used as heat transfer fluids in the Temperature range from 250 ° C to 450 ° C were used, including the following step:
  • Linear silicone oils with trimethylsilyl end stops on both sides are used, among other things, as a heat transfer fluid in solar thermal power plants with a parabolic mirror system (Concentrated Solar Power, CSP for short).
  • the silicone oils are used for several hours a day With a thermal load of up to 425 ° C, the polydisperse mixture equilibrates with the formation of short-chain siloxanes and small cycles.
  • the extreme temperature load leads to a further chemical change in the silicone oil in the long term: chain-forming D-units disproportionate into chain-branching T-units and terminal M-units.
  • This process changes the M: D: T ratio of the silicone oil in the long term, one consequence of which is, for example, an increasing increase in the viscosity of the fluid.
  • the molecular composition changes, but also the chemical-physical data, such as the viscosity - this has an influence on the operability (e.g. the pumpability of the heat transfer fluid).
  • the operability e.g. the pumpability of the heat transfer fluid.
  • a silicone oil can contain between 10 and 60% by weight of low molecular weight linear and cyclic siloxanes; the fluid also typically contains between 5 mol% and 20 mol% of T units. Due to the high proportions of linear compounds such as Si2 and cyclic compounds such as D3, D4 and D5, the reuse of aged silicone oils is severely restricted. However, the aged silicone oils represent a potential source of raw materials for such low molecular weight, linear and cyclic siloxanes.
  • EP1008621 discloses a method for recycling any silicone compound, in particular plastic waste, by targeted degradation in the presence of an alkyl carbonate, an active hydrogen group and an acidic catalyst. A mixture of siloxane monomers and oligomers is obtained.
  • EP0597294 discloses a method for recycling functional methyl- or methyl / phenyl-polysiloxanes to give pure methylpolysiloxanes with any degree of branching / crosslinking by sulfuric acid-catalyzed equilibration in the presence of aluminum-containing silicate and hexamethyldisiloxane. The resulting cyclic and linear siloxanes are separated off by distillation.
  • DE2839652 discloses a process for the production of cyclic dimethylpolysiloxanes by targeted equilibration of linear or branched organopolysiloxane (at least 50% Me 2 Si0 2/2 ) with sulfuric acid, the resulting cycles being separated off in a reactive distillation.
  • Alkaryl; x 3-6) from filler-containing silicone materials / waste by catalytic decomposition with metal hydroxides in the presence of an alcoholic solvent under reduced pressure to strip the resulting cycles from the solvent.
  • EP0739926 discloses a process for the recovery of organoalkoxysilane from polyorganosiloxane by reacting a high molecular weight polysiloxane (1-800 kDa), which has been produced by vulcanization, with an alcoholate and an alkoxysilane at up to 300 ° C.
  • ER0082969 discloses a process for the cleavage of linear polysiloxanes to form organochlorosilanes with hydrogen chloride in aqueous solution in the temperature range from -10 to + 10 ° C. The resulting organosiloxanes are separated off as hydrates.
  • DE19619002Al discloses a process for the production of cyclosiloxanes (primarily D4 and D5) by basic cleavage of linear polysiloxanes by means of hydroxide salts. Examples 1 and 2 describe the separation of the resulting cycles by distillation under reduced pressure (48 mbar).
  • the current state of the art relies on the targeted, acidic as well as basic equilibration of any silicone (oils, rubber, etc.) for the preparation and recovery of small siloxanes.
  • the focus is mostly on the catalytic recovery of small cycles, which can be polymerized, for example; further methods in turn deal with the targeted preparation of polyorganosiloxanes through chemical modification of the material used.
  • a distillative separation of these low-boiling components from high-boiling components enables the separate further use of both fractions.
  • the high boiler fraction can be reused as directly as conventional silicone oils or broken down into their silicone components using known processes and further processed.
  • the low boiler fraction obtained can either be used as a synthesis raw material for polymerizations and / or equilibration reactions or can likewise be split into its silicone building blocks by known processes and processed further.
  • the invention relates to a process for working up methylpolysiloxane mixtures containing (M / D / T) units with a content of T units in the range from 0.1 mol% to 30 mol%, which are used as heat transfer fluids in the temperature range from 250 ° C to 450 ° C, including the following step:
  • (M / D / T) -methylpolysiloxane mixtures in the context of the present invention are to be understood as meaning mixtures of the most varied of siloxanes which are built up from the units M, T and / or D, with individual siloxanes consisting only of D units M units, from M and D units or from M and D and T units, and where M units Me3SiOi / 2 chain end units, T units MeSi0 3/2 chain branching units and D units Me 2 Si0 2/2 chain extension units are.
  • Low boiler fraction (a1) in the context of the present invention is understood to mean the constituents of the methylpolysiloxane mixture which have a boiling point in the range from 20 ° C. at normal pressure according to DIN1343 to 180 ° C. at 20 mbar.
  • High boiler fraction (a2) in the context of the present invention is understood to mean the constituents of the methylpolysiloxane mixture which have a boiling temperature above 180 ° at 20 mbar.
  • the separation by distillation preferably takes place in the temperature range from 10 ° C. to 230 ° C. in a pressure range from normal pressure according to DIN1343 to 5 mbar.
  • the separation by distillation is particularly preferably carried out in the temperature range from 15 ° C. to 200 ° C. in a pressure range from normal pressure according to DIN1343 to 10 mbar.
  • a method comprising the following step is particularly preferred:
  • Another particular embodiment of the invention is a method which further comprises the following step:
  • the single or multi-stage, especially the two-stage, distillation and fractional distillation for example, conventional vacuum distillation apparatus or thin-layer and short-path distillation apparatus are suitable.
  • the process according to the invention is suitable for separating equilibrated, T-unit-containing siloxane mixtures, which were used as heat transfer fluid in the temperature range from 250 ° C. to 450 ° C., in particular in the CSP range, by distillation into high-boiling and low-boiling fractions.
  • the resulting components can either be fed to a further application based on the chemical-physical specifications and their T-unit content or according to known methods such as distillation, reactive distillation,
  • Equilibration, depolymerization, etc. can be chemically processed. This preparation also allows the higher molecular weight constituents of the high boiler fraction (a2) to be separated into (lower molecular weight) constituents, which can then be fed to a further application.
  • constituents of the high boiler fraction (a2) can be, for example, as a damping medium, hydraulic oil, liquid dielectric, water repellent, antifoam, care additive, as a lubricant, as a release agent, as Plasticizer, as a heat transfer fluid in the
  • Another object of the invention is the use of the low boiler fraction (a1) according to one of claims 1-5 or of constituents of the low boiler fraction according to claim 6 as a raw material for chemical syntheses.
  • Use as a raw material for chemical syntheses of silicone oils as heat transfer fluids is particularly preferred.
  • Another object of the invention is the use of the high boiler fraction (a2) according to one of claims 1-5 as a damping medium, hydraulic oil, liquid dielectric, water repellant, antifoam, care additive, lubricant, release agent, plasticizer or heat transfer fluid in the low temperature range.
  • composition of the methylpolysiloxane mixtures was determined by means of GC.
  • Device Agilent GC-3900 gas chromatograph, column MXT5 (60 m x 0.28 mm, 0.25 ⁇ m), carrier gas hydrogen, flow rate 1 ml / min, injector CP-1177, split 1:50, detector FID 39X1 250 ° C. Evaluation in area percent, calibration (siloxanes and n-hexadecane) showed that the values in area% correspond to the same values in weight%.
  • composition of the methylpolysiloxane mixtures were determined by means of GPC.
  • Device Iso Pump Agilent 1200, autosampler Agilent 1200, column oven Agilent 1260 detector, RID Agilent 1200, column Agilent 300 mm x 7.5 mm OligoPore exclusion 4500D, column material highly crosslinked polystyrene / divinylbenzene, eluent toluene, flow rate 0.7 ml / min , Injection volume 10 m ⁇ , concentration 1 g / L (in toluene), PDMS (methylpolysiloxane) - calibration (Mp 28500 D, Mp 25200 D, Mp 10500 D, Mp 5100 D, Mp 4160 D, Mp 1110 D, Mp 311 D) . Evaluation in area%.
  • the viscosity was determined using a Stabinger SVM3000 rotational viscometer from Anton Paar at 25 ° C.
  • the flash points were determined using a flash point measuring device (Seta-Flash Series 3) from Stanhope Seta (UK).
  • methylpolysiloxane mixtures that have a composition comparable to CSP power plant operation
  • 100 milliliters and 600 milliliters of a linear methylpolysiloxane mixture with a defined M: D ratio were placed in a stainless steel autoclave (1 liter total volume, with analog and digital pressure sensors and resistance jacket heating with temperature sensor) and this was then sealed gas-tight. After repeated degassing in vacuo (3 ⁇ 20 mbar, 3 minutes each time), the oil was blanketed with an argon atmosphere without pressure.
  • the autoclave was heated to a defined temperature (internal temperature) for a selected period of time in order to maintain the thermodynamic equilibrium of the methylpolysiloxane mixtures and to bring about the formation of different proportions of branching T units.
  • a defined temperature internal temperature
  • the specific conditions are described in Examples 1-4.
  • T units The equilibration changes the molecular composition, and the extreme stress also results in the formation of branching T units.
  • the methylpolysiloxane mixtures obtained in this way were used for further investigation (GC, GPC, viscosity).
  • GC methylpolysiloxane mixtures obtained in this way were used for further investigation (GC, GPC, viscosity).
  • the formation of T units influences the ratio of the molecular building blocks (M: D: T) and can be quantified via 29 Si-NMR spectroscopy.
  • Silicone oil WACKER HELISOL ® 5A (M: D ratio 1: 4; Wacker Chemie AG) is thermally equilibrated for 1 month at 430 ° C in an autoclave according to the above protocol. Then 106.3 g of the aged fluid are worked up via a Vigreux column. The distillation begins at normal pressure in accordance with DIN1343 up to 150 ° C. (heating bath temperature), and then distilling out under reduced pressure from 20 mbar to 175 ° C. (heating bath temperature). The negative pressure is generated with a rotary vane pump (Fa. Vacuubrand, type RZ5) and via PTFE Young Valve set the resulting pressure with nitrogen. The pressure was measured with a Vacuu-View measuring device from Vacuubrand. The results are summarized in Tables 1 and 2.
  • Valve set the resulting pressure with nitrogen.
  • the pressure was measured with a Vacuu-View measuring device from Vacuubrand. The results are summarized in Tables 1 and 2.
  • Silicone oil WACKER HELISOL ® 5A (Wacker Chemie AG) is subjected to thermal stress in accordance with the above protocol for 1 month at 455 ° C in an autoclave. Then 431.5 g of the aged fluid are worked up via a Vigreux column.
  • Distillation begins at normal pressure in accordance with DIN1343 up to 150 ° C. (heating bath temperature), then distillation is carried out under reduced pressure from 20 mbar to 175 ° C. (heating bath temperature).
  • the negative pressure is generated with a rotary vane pump (from Vacuubrand, type RZ5) and the resulting pressure is set using nitrogen via a PTFE Young valve.
  • the pressure was measured with a Vacuu-View measuring device from Vacuubrand. The results are summarized in Tables 1 and 2.
  • Example 4 comparativative example:
  • Silicone oil with an M: D ratio of 1:16 (available from Wacker Chemie AG) is subjected to thermal stress in the autoclave for 1 month at 425 ° C according to the above protocol. Then 471 g of the aged fluid are worked up using a Vigreux column. The distillation begins at normal pressure in accordance with DIN1343 up to 150 ° C. (heating bath temperature), and then distilling out under reduced pressure from 20 mbar to 175 ° C. (heating bath temperature). The negative pressure is generated with a rotary vane pump (from Vacuubrand, type RZ5) and the resulting pressure is set using nitrogen via a PTFE Young valve. The pressure was measured with a Vacuu-View measuring device from Vacuubrand. The results are summarized in Tables 1 and 2.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Silicon Polymers (AREA)

Abstract

L'invention concerne un procédé de traitement de mélanges de méthylpolysiloxane contenant des unités (M/D/T), avec une teneur en unités T dans la région de 0,1 % en moles à 30 % en moles, qui ont été utilisés en tant que fluides de transfert de chaleur dans une plage de température de 250 à 450 °C, comprenant l'étape suivante : (i) une séparation par distillation à étage unique ou à étages multiples en une fraction à point d'ébullition inférieur (a1) et une fraction de point d'ébullition supérieur (a2) dans une plage de température allant de 0 à 250 °C dans une plage de pression allant de la pression normale (conformément à DIN1343) à 1 mbar.
PCT/EP2020/056343 2020-03-10 2020-03-10 Procédé de traitement de mélanges de (m/d/t)-méthylpolysiloxane à partir d'applications de transfert de chaleur WO2021180308A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202080078136.8A CN114729128B (zh) 2020-03-10 2020-03-10 对来自传热应用的(m/d/t)-甲基聚硅氧烷混合物进行处理的方法
PCT/EP2020/056343 WO2021180308A1 (fr) 2020-03-10 2020-03-10 Procédé de traitement de mélanges de (m/d/t)-méthylpolysiloxane à partir d'applications de transfert de chaleur

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PCT/EP2020/056343 WO2021180308A1 (fr) 2020-03-10 2020-03-10 Procédé de traitement de mélanges de (m/d/t)-méthylpolysiloxane à partir d'applications de transfert de chaleur

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2839652A1 (de) 1978-09-12 1980-03-20 Wacker Chemie Gmbh Verfahren zum herstellen von cyclischen dimethylpolysiloxanen
EP0082969A2 (fr) 1981-12-28 1983-07-06 Hüls Troisdorf Aktiengesellschaft Procédé de scission d'organosiloxanes
EP0597294A1 (fr) 1992-10-23 1994-05-18 Wacker-Chemie Gmbh Procédé de préparation de méthylpolysiloxanes
EP0739926A1 (fr) 1993-12-28 1996-10-30 Tama Chemicals Co., Ltd. Procede de recuperation d'organoalcoxysilane a partir de polyorganosiloxane
DE19619002A1 (de) 1995-05-11 1996-11-14 Rhone Poulenc Chimie Verfahren zur Herstellung von Cyclosiloxanen durch Depolymerisation von Polysiloxanen
WO1998011155A1 (fr) 1996-09-13 1998-03-19 Huntsman, Peter, Harold Procede de recuperation des polysiloxanes de methyle sous forme de cyclosiloxanes
EP1008621A2 (fr) 1998-12-07 2000-06-14 Yazaki Corporation Procédé pour recycler des silicones
DE102012211258A1 (de) * 2012-06-29 2014-01-02 Wacker Chemie Ag Siloxan-Mischungen
DE102015202158A1 (de) * 2015-02-06 2016-08-11 Technische Universität München Verzweigte Organosiloxane als Wärmeträgerflüssigkeit

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB933502A (en) * 1958-12-15 1963-08-08 Gen Electric Unsymmetrical poly (silarylenesiloxane) liquids
US4764631A (en) * 1988-01-15 1988-08-16 Dow Corning Corporation Preparation of cyclopolydiorganosiloxanes via vapor phase rearrangement
US4898956A (en) * 1989-06-27 1990-02-06 Dow Corning Corporation Method to prepare thermo-oxidatively stable phenylmethylsiloxane fluids

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2839652A1 (de) 1978-09-12 1980-03-20 Wacker Chemie Gmbh Verfahren zum herstellen von cyclischen dimethylpolysiloxanen
EP0082969A2 (fr) 1981-12-28 1983-07-06 Hüls Troisdorf Aktiengesellschaft Procédé de scission d'organosiloxanes
EP0597294A1 (fr) 1992-10-23 1994-05-18 Wacker-Chemie Gmbh Procédé de préparation de méthylpolysiloxanes
EP0739926A1 (fr) 1993-12-28 1996-10-30 Tama Chemicals Co., Ltd. Procede de recuperation d'organoalcoxysilane a partir de polyorganosiloxane
DE19619002A1 (de) 1995-05-11 1996-11-14 Rhone Poulenc Chimie Verfahren zur Herstellung von Cyclosiloxanen durch Depolymerisation von Polysiloxanen
WO1998011155A1 (fr) 1996-09-13 1998-03-19 Huntsman, Peter, Harold Procede de recuperation des polysiloxanes de methyle sous forme de cyclosiloxanes
EP1008621A2 (fr) 1998-12-07 2000-06-14 Yazaki Corporation Procédé pour recycler des silicones
DE102012211258A1 (de) * 2012-06-29 2014-01-02 Wacker Chemie Ag Siloxan-Mischungen
DE102015202158A1 (de) * 2015-02-06 2016-08-11 Technische Universität München Verzweigte Organosiloxane als Wärmeträgerflüssigkeit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"Analysis of Large Linear and Cyclic Methylsiloxanes and Computer Calculation of the Chromatographic Data", JOURNAL OF CHROMATOGRAPHIC SCIENCE, vol. 4, 1966, pages 347 - 349

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CN114729128A (zh) 2022-07-08
CN114729128B (zh) 2024-03-22

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