Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
  • B01J20/12—Naturally occurring clays or bleaching earth
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D15/00—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/20—Silicates
  • C01B33/36—Silicates having base-exchange properties but not having molecular sieve properties
  • C01B33/38—Layered base-exchange silicates, e.g. clays, micas or alkali metal silicates of kenyaite or magadiite type
  • C01B33/44—Products obtained from layered base-exchange silicates by ion-exchange with organic compounds such as ammonium, phosphonium or sulfonium compounds or by intercalation of organic compounds, e.g. organoclay material
• • 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
  • C10G25/00—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
  • C10G25/003—Specific sorbent material, not covered by C10G25/02 or C10G25/03
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/10—Refining fats or fatty oils by adsorption

Definitions

• This invention relates to the removal of polyaromatic hydrocarbons from oil or other liquids by adsorption onto a solid substrate.
• Vegetable, animal or fish oils are produced on a large scale for human consumption.
• the production process in the case of vegetable oils, may include drying of the source material, for example coconut flesh, by direct contact with flue gases or using open fires. This can cause the contamination of the oils with small but significant quantities of polyaromatic hydrocarbons.
• animal or fish oils similar contamination can occur due to pollution by discharged aqueous industrial effluents via the food chain.
• animal oil is used herein to include animal fats in liquid form.
• Polyaromatic hydrocarbons are compounds comprising a plurality, that is three or more, fused aromatic rings. Some of these compounds, notably benzo(a)pyrene, are known or suspected carcinogens and it is desirable to reduce their concentration in oils or in aqueous liquids such as the industrial wastes referred to above. Benzo(a)pyrene is often present in about 10% of the total quantity of polyaromatic hydrocarbons and its removal is taken to be an indicator of the concomitant removal of other polyaromatic hydrocarbons. The removal of benzo(a)pyrene may be monitored by reverse phase HPLC analysis using a calibration curve obtained from prepared standard solutions. The benzo(a)pyrene may be eluted in hexane on an alumina column
• United States Patent Specification No. 4916095 dicloses the removal of benzo(a)pyrene from waste water streams by the use of a clay having organic surfactant cations irreversibly bound to the surface.
• a clay having organic surfactant cations irreversibly bound to the surface.
• the clay is an expansible clay, such as a swelling bentonite, it is first reacted with highly charged inorganic cations such as hydroxy aluminium polymeric 7 + cations, which bind strongly to the interlayer cation exchage sites of the clay.
• a subsequent treatment with the cationic surfactant acts to cause irreversible binding of the surfactant only on the surface of the clay.
• Such inorgano-organoclays are effective to reduce the benzo(a)pyrene content of water.
• Cetyl pyridinium chloride-montmorillonite is taught in United States Patent Specification No. 4916095 to be suitable for the absorption of organic wastes from water, is shown to have activity in relation to chlorinated biphenyl or octachlorodioxin but to have litle effectiveness in relation to fluorene or pentachlorophenol and was not tested in relation to benzo(a)pyrene.
• polyaromatic hydrocarbons are removed from oils or other liquids by contact with organoclays bearing certain onium cations.
• the present invention provides a process for reducing the content of polyaromatic hydrocarbons in liquids comprising contacting the liquid with an organoclay in which at least some of the interlayer cation exchange capacity is occupied by organic onium cations having the general formula:
• X represents an atom of nitrogen, phosphorus, antimony or arsenic having a valency of 4 or of oxygen, selenium, sulphur or tin having a valency of 3
• SUBSTITUTESHEET H represents one or more hydrogen atoms
• R represents one or more organic radicals comprising a cyclic group containing conjugated double bonds which is directly bonded to the atom X
• n and m each represent numbers
• n + m is a number equal to the valency of X
• m optionally representing zero.
• X is a nitrogen atom or a phosphorus atom to give an ammonium or phosphonium cation.
• One of the valencies of the atom X will be a delta bond involving two electrons.
• the clays suitable for use according to this invention are layered materials capable of binding an onium compound by ion-exchange such as a silicate, aluminosilicate, aluminophosphate or like material the layers of which have acquired an anionic charge by the replacement of some framework Si, Al or P atoms by atoms of lower valency.
• the adsorbent is a smectite clay mineral or a synthetic analogue of such a mineral since these materials generally have a high cation exchange capacity of from about 50 to 150 m.eq/100 g.
• Smectite minerals may be defined as a group of minerals or phyllosilicates of the 2:1 layer type with the general formulae:
• _I m+ represents exchangeable cations such as Ca++, Mg++, having a valency m, necessary to satisfy the negatively charged lattice
• R2 + represents magnesium or iron
• R 3+ represents aluminium or iron.
• the smectite group of minerals includes the mineral sub-groups mont orillonite,
• Minerals belonging to the montmorillonite (dioctahedral), saponite or hectorite (trioctahedral) groups are particularly preferred for use according to the present invention.
• Fullers earth, is a montmorillonite containing predominantly Ca++ and Mg++ exchangeable cations which is suitable for use according to the present invention.
• the ion-exchange binding of the onium cation with the anionic layered adsorbent may be achieved by treating the adsorbent substrate with a solution or suspension of the onium compound in water or other polar solvent.
• the cation exchange capacity of the substrate is preferably saturated with the onium cations.
• the onium cation is preferably used in excess over the cation exchange capacity of the substrate.
• a suitable quantity of onium cation is above 1.0 but preferably 1.5 to 2.5 times the cation exchange capacity of the substrate.
• the substrate is preferably treated at a concentration of, for example, from 1 to 12% by weight with the onium cation. It is an important factor in achieving an efficient adduction that the substrate be in a highly dispersed state. The presence of shear assists dispersion and a suitable way of attaining this is by means of a high shear stirrer.
• a dispersion agent such as tetrasodium pyrophosphate
• the quantity of dispersing agent may be suitably in the range of 0.1% to 5% and preferably from 1% to 4% by weight of the substrate. If any aggregates of substrate remain undispersed it may be desirable to remove such aggregates by, for example, centrifugation.
• the onium cation may be added to the dispersion of the substrate or may itself be dispersed at, for example, a concentration of from 1% to 6% by weight, and the two dispersions may be mixed while slowly adding the suspension of the onium compound to the dispersion of the substrate.
• the dispersion of the substrate and the mixed dispersions are
• a*_ fc maintained under shear throughout, and for a sufficient time after the mixing has been completed to allow the cation exchange to go to completion.
• a suitable time is for 20 to 120 minutes after mixing has been completed.
• the temperature is maintained throughout at from 10°C to 90°C depending on the thermal stability of the onium cation.
• the derivative resulting from the cation exchange may be filtered and washed free of inorganic cations from the substrate and anions associated with the onium cation. Again depending on the thermal stability of the onium cation it may be necessary to control the temperature of drying carefully to avoid decomposition of the onium cation.
• the onium compound contains one or more cyclic groups containing conjugated double bonds, for example phenyl or substituted phenyl groups, directly connected to or incorporating the atom X of the onium cation.
• the groups R in the above stated formula are not the group containing conjugated bonds but are, for example, aliphatic groups containing from 1 to about 20 carbon atoms.
• one only at most of the groups R comprises a carbon- carbon chain containing more than 5, for example 6 to 20, carbon atoms, for example the hexadecyl group.
• 1 or 2 of the non-aromatic groups is an alkyl group containing from 1 to 5 carbon atoms.
• the group containing the conjugated double bonds may very suitably be a polyaromatic group, for example phenyl or substituted phenyl groups, directly connected to or incorporating the atom X of the onium cation.
• the groups R in the above stated formula are not the group containing conjugated bonds but are, for example,
• f_ . wc ?5 _rr example a naphthalene group.
• further aromatic groups may be connected to the aromatic group R or R ⁇ R ⁇ x via a linking group such as a methylene group or a polymethylene group.
• the Applicant envisages that the electron density in the one or more cyclic groups R containing conjugated double bonds may be reduced by attraction to the onium atom X and that this may alter the character of the said cyclic groups to give them a greater affinity for the polyaromatic hydrocarbon atom which it is desired to adsorb.
• a grouping containing fused conjugated double bond rings such as a pyrene grouping or a benzo(a)pyrene grouping when introduced into an onium compound and ionically bonded via the onium compound to a substrate may be an effective preferential adsorbent for benzo(a)pyrene contained in oils.
• the treatment of a liquid containing polyaromatic hydrocarbons according to this invention may be carried out by contacting the liquid with a body of the organoclay suitably, for example, by passing the liquid through a column or bed of the organoclay or by mixing the organoclay into a body of the liquid in each case allowing sufficient contact time to achieve adsorption of the polyaromatic hydrocarbon onto the organoclay.
• An oil may be treated as such or in miscellar or solution form in a suitable solvent.
• the adsorbent was a Peruvian smectite clay having a cation exchange capacity of 50 to 100 m.eq/100 g. This clay was treated at ambient temperature with double its cation exchange capacity of the onium cation identified in the following Table in the form of a solution in water or ethanol. After 60 minutes the product was water washed and oven dried at 60-80°C.
• a number of volumes (10ml) of a poor quality coconut oil containing 12.1 ( ⁇ 1.0) ppb (parts per 10 9 ) of benzo(a)pyrene were treated with 0.5g of the onium exchanged adsorbent with stirring for 35 minutes at 100°C temperature. The adsorbent was then removed and filtered from the oil which was then analysed for residual benzo(a) yrene. The quantity of benzo(a)pyrene adsorbed was assumed to equate to the difference between the original quantity and the residual quantity.
• Example 1 is according to the invention.
• the organoclay contained no groups containing conjugated double bonds.
• the organoclay contained 4-valent nitrogen in pyridinium, not ammonium, form.
• the group containing conjugated double bonds was connected to the nitrogen atom via a methylene group i.e. was not directly connected *o the nitrogen atom.
• Example 2 there were no non-aromatic substituents as is preferred according to the invention.
• Exa rle 3 there were no short chain alkyl groups as is preferred according to the invention.
• Example 21 is according to the invention.
• Example 22 there is no short chain alkyl group as is preferred and in Example 23 the 4-valent nitrogen atom is in pyridinium form.
• 2,2 diphenyl propylamine is a new compound.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Life Sciences & Earth Sciences (AREA)
• Analytical Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Inorganic Chemistry (AREA)
• Wood Science & Technology (AREA)
• General Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Geochemistry & Mineralogy (AREA)
• Microbiology (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)

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Cited By (5)

Citations (4)

• 1990
  • 1990-10-17 GB GB909022472A patent/GB9022472D0/en active Pending
• 1991
  • 1991-10-01 ZA ZA917837A patent/ZA917837B/xx unknown
  • 1991-10-07 AU AU86620/91A patent/AU8662091A/en not_active Abandoned
  • 1991-10-07 WO PCT/GB1991/001736 patent/WO1992006758A1/en active Application Filing
  • 1991-10-14 MX MX9101578A patent/MX9101578A/es unknown
  • 1991-12-17 TW TW080109943A patent/TW197954B/zh active

Patent Citations (4)

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