Patent GB-874237-A (GB)
Title: Improvements in and relating to the preparation of hydrogenation products from halides of elements of groups ó= and ó( of the periodic system
Inventor: SUNDERMEYER WOLFGANG
IPC: C01B33/107
Filed: 1958-08-07
Abstract: <PICT:0874237/IV (a)/1> An organo halide of silicon is hydrogenated by contact with an alkali, or alkaline earth metal, hydride, or hydride ions in a melt of a non-oxidizing halide of a metal of Group I or II, or mixture of such halides.  Hydrides of Li, Na, K, Rb, Cs, Ca, Sr, Ba, and Ra are referred to and it is preferred to electrolyse the metal halide formed to separate alkali or alkaline earth metal and halogen, and form hydride by reacting the metal with hydrogen either simultaneously, or sequentially, with the hydrogenation reaction.  The halides of silicon may include as organic substituents, e.g. CH3-, C2H5-, or C6H5.  The preferred melt is a eutectic of LiCl and KCl with, or without, an alkaline earth metal chloride but a number of mixtures of two and three alkali, alkaline earth, and silver halides are specified.  A melt 4 of halide e.g. LiCl is contained in steel U-tube 1 having ceramic tube liner 9 in leg 2, heaters 13, 14 and 15, and cooler 16.  D.C. is applied to graphite anode 8 and iron tube cathode 11, and halogen is liberated at 19, while alkali or alkaline earth metal floats on the surface 6. Cooler 16 is then operated to solidify the melt at 18 and isolate the two portions of the tube and hydrogen is passed through cathode tube 11, while heater 13 maintains adjacent melt liquid. When hydride has been formed with the metal, silicon halide may be injected through tube 11 preferably in a hydrogen carrier and the hydrogenated product is withdrawn at 20.  Cooler 16 is turned off and electrolysis of the hydride repeated.  In an alternative, (Fig. 2, not shown), a circular vessel with an annular anode is divided into two zones by a circular, perforated, tantalum partition, the preforations of which can be closed by displacement of a second perforated tube with a closed bottom to effect mechanical isolation of the zones.  The tubular cathode is at the centre of the vessel.  Apparatus for continuous operation may have three upwardly directed legs (Fig. 3, not shown) with electrodes in the two outer legs as in Fig. 1.  The halide of silicon is fed into the bottom of the central leg, which may be funnel-shaped to prevent escape of hydrogenated product into the outer legs, and reacts with the hydride ions passing to the anode. The hydride ions have been formed by electrolysis of the hydride produced at the cathode by continuous introduction of H2 to react with alkali or alkaline earth metal.  A layer of solid melt may protect the inside wall against corrosion.  Alternatively, (Figs. 4, 5 not shown), a circular vessel may be divided into three zones by circular partitions which may be perforated.  In the continuous process the H2 carrier may be recovered from the product and recycled, and the liberated halogen may be used to form the Group III or IV halide.ALSO:<PICT:0874237/IV (b)/1> An organo halide of boron or germanium is hydrogenated by contact with an alkali, or alkaline earth metal, hydride, or hydride ions in a melt of a non-oxidising halide of a metal of Groups I or II, or mixture of such halides. Hydrides of Li, Na, K, Rb, Cs, Ca, Sr, Ba, and Ra are referred to and it is preferred to electrolyse the metal halide formed to separate alkali or alkaline earth metal and halogen, and form hydride by reacting the metal with hydrogen either simultaneously, or sequentially, with the hydrogenation reaction.  The halides of boron or germanium may include as organic substituents, e.g. CH3-, C2H5-, or C6H5.  The preferred melt is an eutectic of LiCl and KCl with, or without, an alkaline earth metal chloride but a number of mixtures of two and three alkali, alkaline earth, and silver halides are specified.  A melt 4 of halide, e.g. LiCl is contained in steel U-tube 1 having ceramic tube liner 9 in leg 2, heaters 13, 14 and 15, and cooler 16.  D.C. is applied to graphite anode 8 and iron tube cathode 11, and halogen is liberated at 19, while alkali or alkaline earth metal floats on the surface 6. Cooler 16 is then operated to solidify the melt at 18 and isolate the two portions of the tube and hydrogen is passed through cathode tube 11, while heater 13 maintains adjacent melt liquid. When hydride has been formed with the metal, halide of boron or germanium may be injected through tube 11 preferably in a hydrogen carrier and the hydrogenated product is withdrawn at 20.  Cooler 16 is turned off and electrolysis of the hydride repeated.  In an alternative, (Fig. 2 not shown), a circular vessel with an annular anode is divided into two zones by a circular, perforated, tantalum partition, the perforations of which can be closed by displacement of a second perforated tube with a closed bottom to effect mechanical isolation of the zones.  The tubular cathode is at the centre of the vessel.  Apparatus for continuous operation may have three upwardly directed legs (Fig. 3 not shown) with electrodes in the two outer legs as in Fig. 1.  The halide of boron or germanium is fed into the bottom of the central leg, which may be funnel shaped to prevent escape of hydrogenated product into the outer legs, and reacts with the hydride ions passing to the anode.  The hydride ions have been formed by electrolysis of the hydride produced at the cathode by continuous introduction of H2 to react with alkali or alkaline earth metal.  A layer of solid melt may protect the inside wall against corrosion.  Alternatively, (Figs. 4, 5 not shown), a circular vessel may be divided into three zones by circular partitions which may be perforated.  In the continuous process the H2 carrier may be recovered from the product and recycled, and the liberated halogen may be used to form the boron or germanium halide.ALSO:<PICT:0874237/III/1> A halide, as defined, of an element of Group III or IV of the Periodic Table is hydrogenated by contact with an alkali, or alkaline earth metal, hydride, or hydride ions in a melt of a non-oxidizing halide of a metal of Group I or II, or mixture of such halides.  Hydrides of Li, Na, K, Rb, Cs, Ca, Sr, Ba, and Ra are referred to and it is preferred to electrolyse the metal halide formed to separate alkali or alkaline earth metal and halogen, and form hydride by reacting the metal with hydrogen either simultaneously, or sequentially, with the hydrogenation reaction.  The halides of the Group III or IV elements include halides containing organic substituents, e.g. CH3-, C2H5-, or C6H5-, and such compounds as K2SiF6 and K2GeCl6, and referenc is made to the preparation of SiH4, SiHX3, SiH2X2, p  and SiH3X from SiX4 where X is halogen, Si2H6 from Si2Cl6, B2H6 from BBr3, and GeH4 and organo silanes, boranes and germanes.  The preferred melt is a entectic of LiCl and KCl with, or without, an alkaline earth metal chloride, but a number of mixtures of two and three alkali, alkaline earth, and silver halides are specified.  A melt 4 of halide, e.g. LiCl, is contained in steel U-tube 1 having ceramic tube liner 9 in leg 2, heaters 13, 14 and 15, and cooler 16.  D.C. is applied to graphite anode 8 and iron tube cathode 11, and halogen is liberated at 19, while alkali or alkaline earth metal floats on the surface 6. Cooler 16 is then operated to solidify the melt at 18 and isolate the two portions of the tube and hydrogen is passed through cathode tube 11, while heater 13 maintains adjacent melt liquid. When hydride has been formed with the metal, SiCl4 may be injected through tube 11 preferably in a hydrogen carrier and the hydrogenated product is withdrawn at 20.  Cooler 16 is turned off and electrolysis of the hydride repeated.  In an alternative, (Fig. 2 not shown), a circular vessel with an annular anode is divided into two zones by a circular, perforated, tantalum partition, the perforations of which can be closed by displacement of a second perforated tube with a closed bottom to effect mechanical isolation of the zones.  The tubular cathode is at the centre of the vessel.  Apparatus for continuous operation may have three upwardly directed legs (Fig. 3 not shown) with electrodes in the two outer legs as in Fig. 1.  The halide of the Group III or IV element is fed into the bottom of the central leg, which may be funnel shaped to prevent escape of hydrogenated product into the outer legs, and reacts with the hydride ions passing to the anode.  The hydride ions have been formed by electrolysis of the hydride produced at the cathode by continuous introduction of H2 to react with alkali or alkaline earth metal.  A layer of solid melt may protect the inside wall against corrosion.  Alternatively, (Figs. 4, 5 not shown), a circular vessel may be divided into three zones by circular partitions which may be performated.  In the continuous process the H2 carrier may be recovered from the product and recycled, and the liberated halogen may be used to form the Group III or IV halide.