Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/04—Purification; Separation; Use of additives by distillation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
  • C07C2/02—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons
  • C07C2/04—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation
  • C07C2/06—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation of alkenes, i.e. acyclic hydrocarbons having only one carbon-to-carbon double bond
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
  • C07C7/177—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by selective oligomerisation or polymerisation of at least one compound of the mixture

Definitions

• the invention relates to a process for the preparation of oligomers by continuous oligomerization of butenes, which is characterized in that a) an initial stream comprising 1-butene and 2-butene in a total concentration of 10 to 70 wt.% And 10 to 60 wt. % iso-butane is used (referred to below as output current 1) b) this output current 1 is converted to more than 60% by weight of the 1-butene contained in the output stream 1, but less than 50% by weight of that contained in the output stream 1 C) the oligomers obtained in b) are separated off and, if appropriate, fed to a further workup and the remaining stream is subjected to a work-up by distillation. D) the residual stream iso-butane is removed by distillation distillative workup d) obtained is de-enriched in isobutane stream (hereinafter called output stream 2) to oligomers.
• output current 2 an initial stream comprising 1-butene and 2-butene in a total concentration of 10
• Oligomers of butene such as octenes and dodecenes, are of great importance as starting materials for further chemical syntheses and as constituents of fuels such as gasoline, die or kerosene.
• these oligomers z. B. converted by hydroformylation and subsequent hydrogenation in alcohols.
• the resulting alcohols are suitable for the preparation of plasticizers and surfactants.
• WO 00/69795 describes an oligomerization process in which the oligomerization takes place in a plurality of stages, that is to say in a plurality of successively adiabatically operated reaction zones, on a heterogeneous nickel-containing oligomerization catalyst.
• the streams used for an oligomerization should have the highest possible content of linear butenes.
• a content of inert butanes reduces the space-time yield.
• n- and iso-butane are therefore separated off before the oligomerization is carried out by a multistage process.
• the multi-stage process includes a Extractive distillation, a distillative workup of the resulting sump and washing the overhead fraction.
• raffinate 2 streams can be used, which can be taken from steam crackers or refineries or are also available as end products of other chemical processes, dehydrogenations or MTO processes (methanol to olefines).
• raffinate 2 streams are C4 streams.
• butadiene and isobutene have generally been largely removed by previous process steps.
• Known methods for the separation of butadiene are systems for the extraction of butadiene or the selective hydrogenation of butadiene to butenes.
• Refinery raffinate 2 streams generally contain significantly less oligomerization suitable 1- and 2-butenes than those from steam crackers.
• the reactors and the workup portion of the oligomerization must be designed to be large enough to achieve a satisfactory yield of oligomers and effective utilization of the raffinate-containing linear butenes.
• the object of the present invention was therefore to provide a corresponding method. Accordingly, the method defined above was found.
• a suitable starting stream 1 contains predominantly hydrocarbons with 4 C atoms
• C 4 -hydrocarbons in particular it consists of more than 85% by weight, preferably more than 95% by weight, more preferably more than 99% by weight, of C 4 -hydrocarbons.
• feed stream 1 contains no or only minor amounts of butadiene and isobutene. Where originally available, these are generally largely removed by previous process steps.
• Known methods for the separation of butadiene are systems for the extraction of butadiene or the selective hydrogenation of butadiene to butenes. Isobutene can z. B. by preparation of methyl tert-butyl ether (MTBE) or Isobutyltertiär- butyl ether (IBTBE) are separated with subsequent cleavage.
• MTBE methyl tert-butyl ether
• IBTBE Isobutyltertiär- butyl ether
• the following weights are based on the total weight of the output stream 1.
• the starting stream 1 preferably contains less than 3% by weight, in particular less than 1% by weight, particularly preferably less than 0.3% by weight, of butadiene.
• the starting stream 1 preferably contains less than 3% by weight, in particular less than 1% by weight, more preferably less than 0.3 or less than 0.1% by weight, of isobutene.
• Output stream 1 contains 1-butene and 2-butene in a total amount of 10 to 70 wt.%.
• 1-butene and 2-butene are linear butenes with the double bond in 1, 2 or in the 2,3-position.
• the starting stream contains 1-butene and 2-butene in a total concentration of 20 to 60% by weight, more preferably in a total concentration of 30 to 60% by weight, most preferably in a total concentration of 40 to 60% by weight.
• Output stream 1 contains both 1-butene and 2-butene.
• the starting stream contains from 1 to 30% by weight of 1-butene and from 1 to 40% by weight of 2-butene, particularly preferably
• the content of 1-butene is very particularly preferably 5 to 30% by weight and of 2 to butene 20 to 40% by weight, the total content of the two butenes being 40 to 60% by weight.
• Starting stream 1 contains 10 to 60% by weight of isobutane, in particular 15 to 50% by weight and particularly preferably 20 to 50% by weight of isobutane.
• feed stream 1 contains iso-butane in an amount of 30 to 50 weight percent.
• the output stream 1 n-butane and other ingredients, including, for. B. possibly small amounts of butadiene, isobutene (see above) or impurities count.
• output stream 1 also contains n-butane, e.g. In an amount of 0 to
• 60% by weight in particular 5 to 60% by weight, preferably 5 to 30% by weight.
• output current 1 is composed entirely
• starting stream 1 is composed overall
• output stream 1 in total from 5 to 30% by weight of 1-butene
• output current 1 is composed entirely
• oligomerization takes place.
• oligomerization is understood here as a dimerization.
• 1-butene and 2-butene are converted to octenes (dimerization), or further to dodecenes (trimerization) or higher oligomers (C16 or more, in short C16 +).
• dimerization almost exclusively produces iso-octenes, e.g. mono- or di- or trisubstituted C8-olefins (such as 3-methyl-heptene or 3,4-dimethyl-hexene). Accordingly, almost exclusively iso-dodecenes are formed as trimer.
• octene in this patent application is intended to encompass octenes of any kind and, in particular, octene mixtures, such as those resulting from the oligomerization, that is, mixtures of substantially different iso-octenes.
• dodecene in this patent application is intended to include dodecenes of any kind and, in particular, for dodecene mixtures, such as those resulting from the oligomerization, that is to say for mixtures essentially of different isododecenes.
• Methods of oligomerization are known and e.g. in EP-A 1724 249 or WO 00/69795.
• the oligomerization preferably takes place in the presence of a heterogeneous catalyst.
• heterogeneous catalysts are e.g. acidic catalysts into consideration.
• nickel-containing heterogeneous catalysts Preference is given to nickel-containing heterogeneous catalysts, particular preference is given to nickel in the form of nickel oxide (NiO).
• the heterogeneous catalyst may contain other ingredients, e.g. S1O2, ⁇ 2, ZrÜ2 or AI2O3 as carrier material.
• the oligomerization in process step b) can be carried out in one reaction zone or in a plurality of reaction zones connected in parallel or in series.
• the oligomerization takes place at temperatures of 30 to 180 ° C, particularly preferably at temperatures of 30 to 140 ° C.
• the oligomerization is carried out at pressures of 10 to 300 bar, more preferably at pressures of 15 to 100 bar.
• Suitable reactors are, for example, cylindrical reactors charged with the catalyst. These are flowed through by the preferably liquid starting mixture 1 from top to bottom or vice versa. For several reaction zones are correspondingly in series or in parallel switched reactors used or a reactor which is subdivided into several reaction zones accordingly.
• the oligomerization is carried out in process step b) in only one reaction zone.
• Output stream 1 is reacted in process step b) until more than 60% by weight of all 1-butenes present in the starting stream 1, but less than 50% by weight of the 2-butenes present in the starting stream 1, are converted into oligomers.
• starting stream 1 is reacted in process step b) until more than 80% by weight of all 1-butenes present in the starting stream 1 but less than 50% by weight of the 2-butenes present in the starting stream 1 are converted into oligomers.
• starting stream 1 is converted in process step b) until more than 85% by weight of all 1-butenes present in the starting stream 1 but less than 35% by weight of the 2-butenes present in the starting stream 1 are converted into oligomers.
• Very particular preference is given to converting starting stream 1 into process step b) until more than 85% by weight of all 1-butenes present in the starting stream 1 but less than 25% by weight of the 2-butenes present in the starting stream 1 are converted into oligomers.
• the achieved conversion of 1-butene and 2-butene can be easily determined by gas chromatographic quantification of the remaining amount of 1- and 2-butene.
• Process step c) is the separation of the oligomers formed in b).
• the oligomers are preferably separated by distillation, wherein the oligomers are discharged with the bottom and the C4 fraction is removed overhead.
• the oligomers are fed to a further workup.
• a separation into the fractions octene, dodecene and C16 + takes place.
• the separation can be carried out in a known manner by distillation.
• the total amount of the residual stream obtained in c) and now to be distilled in d) is preferably from 5 to 95% by weight, in particular from 30 to 95% by weight, particularly preferably from 50 to 90% by weight and very particularly preferably from 60 to 85% by weight. of the output current 1.
• the residual current consists in particular of a total of
• the residual current particularly preferably consists overall of from 20 to 50% by weight of 2-butene
• the distillation in process step d) can be carried out by known processes.
• the distillation is preferably carried out at head temperatures of from 50 to 90.degree. C., particularly preferably from 60 to 80.degree. C. and very particularly preferably from 65 to 75.degree. C., and in the case of bottoms. Temperatures of 60 to 1 10 ° C, more preferably carried out from 70 to 100 ° C and most preferably from 80 to 90 ° C.
• the distillation is preferably carried out at bottom pressures of 8 to 15 bar, more preferably from 9 to 13 bar and most preferably from 10 to 12 bar.
• the pressure loss over the entire column can be, for example, 0.1 to 0.5 bar.
• Suitable distillation columns are both packed columns and columns with built-in column trays (tray columns). Also suitable are columns which contain both fillers and bottoms, e.g. Packed beds in parts of the columns and corresponding internals (steel sheets) in other parts. Preferred is a tray column.
• the tray column can, for. B: 40 to 150, in particular 80 to 120 soils included
• the distillation column may preferably contain at least 5, in particular at least 10 theoretical trays.
• the number of theoretical trays may be e.g. B. a total of 10 to 100, in particular -20 to 100 or 30 to 100.
• the distillation column contains a total of 40-70 theoretical plates.
• the column is divided into a stripping section and a reinforcing section; the driven part may e.g. 25-40 theoretical plates and the reinforcing part contain 15-30 theoretical plates.
• distillation preferably more than 60 wt.%, In particular more than
• waste stream The separated iso-butane and optionally further separated compounds (hereinafter referred to collectively as waste stream) are preferably condensed and can be used for other purposes.
• the waste stream consists in particular of
• the waste stream is particularly preferably from 70 to 95 wt.% Iso-butane
• the waste stream very particularly preferably consists of 80 to 95% by weight of isobutane
• the output stream 2 obtained in d) is in turn converted into oligomers in process step e).
• Starting stream 2 is preferably more than 40% by weight, in particular more than 50% by weight and very particularly preferably more than 60% by weight of 2-butene.
• Output current 2 preferably consists of a total
• Output stream 2 particularly preferably consists overall of from 50 to 80% by weight of 2-butene
• Output stream 2 very particularly preferably consists overall of 60 to 70% by weight of 2-butene
• the work-up of the oligomers obtained in b) is carried out together with the oligomers obtained in e).
• the oligomers from b) and from e) are fed to a common distillation for separation into octene, dodecene and C16 +.
• the oligomers obtained overall in process steps b) and e) are preferably a mixture of 70 to 100% by weight, in particular about 75 to 90% by weight, of octene
• the residue obtained is a mixture rich in n-butane, which preferably contains 1-butene and 2-butene, if appropriate in a total amount of less than 25% by weight, particularly preferably less than 20% by weight.
• This mixture can be used for other purposes.
• the process according to the invention is a continuous process, therefore preferably all the above process steps are operated continuously.
• streams having a low content of linear butenes (1-butene and 2-butene), eg raffinate-2 streams from refineries, can be oligomerized with high space-time yield.
• the capacity of the reactors and processing parts can be used optimally.
• the 1- and 2-butenes present in the starting stream 1 can be converted into more than 85% by weight, in particular more than 90% by weight, into oligomers in total.
• it can also be easily carried out in existing oligomerization plants. In general, only a few equipment changes are necessary.
• the method according to the invention therefore permits flexible adaptation to different raw material sources. In particular, in the case of a change from C 4 sources with a high content of butenes to those with a low content of butenes, an apparatus adaptation and implementation of the method according to the invention is easily possible.
• a process was simulated in which the starting stream is oligomerized in a first stage and oligomers are separated off (process steps a, b and c), from which residual isoButane is separated by distillation (process step d) and the isobutane subsequently obtained.
• poor stream is oligomerized again (process step e), the oligomerization in e) takes place in two stages.
• the oligomers obtained in the oligomerization are fed to a joint workup in which the oligomers are separated into octene, dodecene and higher oligomers (C16 and higher oligomers, summarized as C16 +).

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• 2012
  • 2012-10-25 WO PCT/EP2012/071106 patent/WO2013075905A1/de not_active Ceased
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