Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G73/00—Recovery or refining of mineral waxes, e.g. montan wax
  • C10G73/02—Recovery of petroleum waxes from hydrocarbon oils; Dewaxing of hydrocarbon oils
  • C10G73/24—Recovery of petroleum waxes from hydrocarbon oils; Dewaxing of hydrocarbon oils by formation of adducts
• • 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
  • C07C7/152—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by forming adducts or complexes

Definitions

• urea dewaxing process A second product obtained from the mineral oil filtrate by way of this so-called urea dewaxing process is a hydrocarbon mixture which, as a result of the reduced n-paraffin content, has a lower pour point than the charge material.
• This urea dewaxing process may becarried out with crystalline urea, advantageously admixed with minor amounts of such materials as water and methanol as an activator.
• aqueous or alcoholic urea solutions' may also be used in this process.
• the adduct formation is normally carried out at a temperature of from about to 40C, using aqueous urea solutions saturated at an elevated temperature, for example, about 70C.
• Suitable oil solvents include low moleculear weight alcohols and ketones, low boiling hydrocarbons such as butane, pentane, isopentane,
• hexane and the like, and halogenated hydrocarbons such as dichloromethane.
• German patent no. 1,098,657 discloses a process by which the n-paraffin-urea adduct is obtained as a dustlike powder having a medium particle size of or below about 0.1 mm, in the form of fine to coarse particles or as a very viscous aqueous slurry.
• the form of the adduct depends, among other factors, on the type of urea solvent used, if one is used, as well as on the concentration and amount of the urea solution; further, on the type of oil solvent used for diluting the mineral oil and, last but not least, on the adduct-forming temperature.
• the dust-like adduct hereinafter called powder adduct, yields a very pure n-paraffin.
• German patent no. 1,105,090 discloses a process wherein in a-first stage a coarse-grained adduct is produced, and in a second stage this adduct is stirred with a suitable oilsolvent and cooled to form powder adduct. The second stage employs what is termed a repulping operation.
• German patent no. 1,098,657 discloses the influence of the adduct-forming temperature on the form of the adduct; powder adduct is stable only below a defined temperature limit depending, among other factors, on the type of oil solvent used. If, for example, 100 parts by volume of a mineral oil boiling in the range of from 307 to 415C are reacted with 100 parts by volume of aqueous urea solution saturated at C., 300 parts by volume of dichloromethane (DCM) as oil solvent, powder adduct is obtained if the adduct-forming temperature is below 27C.
• DCM dichloromethane
• An adduct in powdery form is formed in a urea dewaxing process at a temperature range of about 20 to 40C. by admixing with the n-paraffin-containing mineral oil distillate an organic solvent of 70 to volume percent of a C C hydrocarbon and 30 to 5 percent of ahigher boiling-organic compound such as methylisobutylketone.
• the solvent combination has the concomitant. advantage of permitting the effective separation of the powdery. adduct fromthe distillate-solvent mixture by centrifuging.
• a particularly advantageous and preferred embodiment of the process of the invention is to conduct the reaction at a temperature of between about 20 and 40C and prepare n-paraffin-urea powder ad a full jacket centrifuge. 5 duct having an average particle size of about 0.1 mm
• the admethyllsobutylketohe lt has further been duct formation was conducted up to or close to this found that miXtufeS of from about 95 to Particularly upper temperature limit.
• the powder adduct obtained about 90 to Volume Percent of allphatle, eyeloall" was separated from the liquid by filtration. Then, it was Phatle or aromatic s s hydrooarbons, for example, washed at adduct-forming temperature, using the same lsopehtahe, hexane or benZene, and from about5 to 30, type and same amount of solvent or solvent mixture Preferably about 10 to 20, volume percent of MlBK, employed in the adduct-forming step.
• ncorhrherelally attraetlve temperature range of about paraffin yield in the Table designates the content by 20 to C, but they are also excellent wash agents, so i h f f i b d on Charge material, efficient in freeing powder adduct and also fine-grained mi upon decomposition of the powder addu
• the to coarse-grained n-paraffin-urea adducts from isopar- 5 expression i f fi designates the afflos and other eohstltuerlts y Washlhg, P P portion of n-paraffins in the decomposition product.
• the first solvent i.e., hexane (Runs 5 ring.
• this dispersion can be MIBK in amounts of about 5 and 10 volume percent heated to a temperature substantially above the ad- (based on said first solvent), respectively.
• duct-forming temperature without thereby causing the Table I, the temperature limits for the formation of the adduct to conglomerate or cake. If these dispersions desired adduct were thereby raised quite considerably.
• Run No. 7 Gas oil, parts by volume 100 100 Aqueous urea sol. (70C saturation),- parts by volume 60 60 1st solvent, benzene benzene parts by volume 210 200 2nd solvent, MIBK MIBK parts by volume 10 20 Upper temperature limit, powder adduct, C 32 61 Adductforming temperature, C 25 25 n-Paraffin yield, wt.% 19.3 19.6 Purity of n-paraffin,
• non-filtcrable gel EXAMPLE lI A-spindle oil 0 boiling in the range of from about 317 to 420C (corresponding to a carbon number range of between about 14 and 28) and containing about 16 wt. percent of n-paraffins was used. 100 parts by volume of said spindle oil were diluted with 200 parts by volume of an oil solvent or solvent mixture and reacted at temperatures of 20 or C with parts by volume of an aqueous urea solution, saturated at C. The results are set forth in Table II below.
• Comparative Runs 9, 10 and 13 were conducted with pure hexane as solvent and with an adduct-forming temperature of 20C. A fine-grained adduct (average particle size 0.1 to 0.3 mm) resulted. In comparative Runs 15, 16 and 19 an adduct having a particle size of from about 0.3 to 0.6 mm was formed at 35C. Powder adduct (average particle size about 0.1 or less) was obtained only at a temperature of 8C or lower. At higher adduct-forming temperatures, and with hexane as solvent, a sticky adduct was obtained, which showed no further reaction. In Runs 11, 12, 14, 17, 18 and 20, MIBK was substituted for about 5 volume percent of said hexane.
• the av erage particle size of the adduct was reduced to 0.1 mm or less.
• the n-paraffins obtained from the runs using MIBK as a diluent component were of greater purity than those obtained in the comparative runs using hexane.
• a process according to claim 1 wherein the vol- In a Process for the recover) of n'parafflns from ume percent of C -C hydrocarbon is 80 to 90 volume mineral oil distillates comprising reacting the mineral percent d h volume percent f h r h oil, diluted with an organic solvent, at a temperature of ik r i 20 to 10 volume percent 20 to 40C, with an aqueous or alcoholic urea solution 3,
• a powdery ment which comprises diluting the mineral Oll distillate adduct having an average particle size of 0.1 mm. or charge material in the adduct-forming step with an orl i f d i h dd f i step.
• ganic solvent which is a solvent mixture consisting es- 7.
• a process according to claim 1 wherein the solvent sentially of from about 70 to 95 volume percent of a mixture is employed as the organic solvent to wash the C -C hydrocarbon and of from about 30 to 5 volume adduct and to decompose the adduct. percent of methylisobutylketone. 1 1

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• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Analytical Chemistry (AREA)
• Water Supply & Treatment (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (4)

• 1972
  • 1972-04-27 DE DE2220594A patent/DE2220594C3/de not_active Expired
• 1973
  • 1973-04-04 IT IT22582/73A patent/IT987057B/it active
  • 1973-04-19 GB GB1901173A patent/GB1421224A/en not_active Expired
  • 1973-04-25 US US00354284A patent/US3847791A/en not_active Expired - Lifetime
  • 1973-04-26 JP JP48048326A patent/JPS5062904A/ja active Pending
  • 1973-04-26 CA CA169,580A patent/CA1005082A/en not_active Expired
  • 1973-04-26 BE BE130461A patent/BE798771A/xx unknown
  • 1973-04-26 FR FR7315130A patent/FR2182131B1/fr not_active Expired
  • 1973-04-27 NL NL7305962A patent/NL7305962A/xx not_active Application Discontinuation

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