US 3793185 A
A novel use for sorbents involving the selective removal of heavy metals from liquid streams has been discovered. More specifically it has been discovered that these sorbents selectively remove alkyl lead moieties from gasoline. The sorbents are comprised of metal halides (preferably tin tetrachloride or antimony pentachloride) bonded to a suitable substrate through at least one amine or alkyl halide functional group. The sorbents can be effectively regenerated.
Description (OCR text may contain errors)
United States Patent 1191 Whitehurst et al.
14 1 Feb. 19,1974
 SORBENT FOR REMOVAL OF HEAVY 3,176,041 3/1965 Ayers 208/263 METALS 3,751,507 8/1973 2,745,793 5/1956 Jezl et al 208/!  In en s: Darrell Whitehursi, Tltusville; 3,213,033 10/1965 Hindin et al. 252 413 Stephen A. Butter, East Windsor; 2,504,134 4/1950 Kharasch 208/251 Paul G. Rodewald, Rocky Hill, all of NJ. I Primary Examiner-Delbert E. Gantz  Assrgnee: Mobll Oll Corporation, New York, Assistant Examiner juanita Nelson Attorney, Agent, or Firm-Andrew L. Gaboriault; Mi-  Filed; May 73 chael G. Gilman; Coe A. Bloomberg  Appl. N0.: 365,358
Related US. Application Data  ABSTRACT  Continuation-impart of Ser. No. 319,099, Dec. 27,
1972- I A novel use for sorbents involving the selective removal of heavy metals from liquid streams has been 208/251 208/252, 208/253 discovered. More specifically it has been discovered 252/414 that these sorbents selectively remove alkyl lead moi- [Sl] Int. Cl C10g 17/00 eties from gasoline The sorbems are comprised f Fleld of Search 208/251, 253; metal halides (preferably tin tetrachloride or antimony 252/411, 413, 414 pentachloride) bonded to a suitable substrate through at least one amine or alkyl halide functional group.  References Clted The sorbents can be effectively regenerated.
UNITED STATES PATENTS 2,453,138 10/1948 Kharasch 208/251 34 Claims, 12 Drawing Figures 5 6O a: .n 50 1L 3O O SPECTRO. METHOD 2O X Pb ANALYSIS 1 I 1 I v I 500 I000 2000 3000 CC TREATED LEAD REMOVAL CAPACITY OF PR-46(I2LHSV) SiOz GASOL1NE(.38gPb/go1)- I PATENTED 3.793.185-
SHEET 1 OF 8 PATENIEU FEB I 9 I974 SHEET 7 OF 8 FIGUREH Pb CONTENT OF EFFLUENT vs. CONTACT TIME (SnCl ACTIVE HALOGEN RESIN 88- I3) PAIENTEUFEB 1 9 m4 SHLU 8 (If 8 O V X m L 5 0 w -m X H 9 2 L I O E '0 R 7 U G I l O CI '0 5 x o 3 X I O O m O O O O O O O O O O O W 9 8 7 6 5 4 3 2 I Qm O2mmnn cc TREATED LEAD REMOVAL CAPACITY AND CONTACT TIME CH3- SnCI4( ss-a INFLUENT Pb CONC.= 053g /go|.
SORBENT FOR REMOVAL OF HEAVY METALS RELATED CASE This application is a continuation-in-part of now pending U.S. application Ser. No. 319,099 filed Dec. 27, 1972.
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention deals with the removal of metals from compositions containing such metals as organic or inorganic compounds. It more particularly refers to removal of lead from gasoline.
The need for the removal of metals is evidenced by the fact that their presence in hydrocarbon charge stocks conducted to catalytic cracking and catalytic reforming process units is known to poison and shorten the life of the catalyst with which such metal contaminated stocks come into contact.
1t is also desirable to remove trace metals from lubricating oils or to recover soluble metal catalysts from reactor effluents or polymer solutions. The removal of heavy metals such as mercury, silver, calcium and the like from the water efiluents of chemical or photographic plants is also highly desired from an ecological standpoint.
Unburned hydrocarbon, carbon and carbon monoxide emissions are regarded by many as representing a substantial source of air pollution. These engine emissions are subject to photo-chemical reaction in the atmosphere, providing what has been termed smog, which is an irritant of lachrymal and respiratory system tissues.
The incompletely oxidized carbon, e.g., carbon monoxide and unburned hydrocarbons, present in engine exhaust is the result of incomplete combustion of the hydrocarbon fuel in the engine combustion chamber. Complete oxidization of such carbon monoxide and/or hydrocarbons transforms such to carbon dioxide and water, probably in the form of steam due to the high combustion temperature. Neither carbon dioxide nor steam is considered a harmful emission.
Various means have been employed to reduce or eliminate carbon monoxide and unburned hydrocarbon emissions. One approachhas been to pass the combustible exhaust gases through a catalytic converter located in the engine's exhaust system where the carbon monoxide and hydrocarbons are catalytically oxidized,
usually by the introduction of supplemental air, to carbon dioxide and water.
It is known that residues of alkyl lead from combustion of leaded gasoline tend to poison catalysts available for oxidizing unburned hydrocarbons and carbon monoxide in an engine exhaust. Such poisoning severely shortens the useful life of exhaust combustion catalysts. Furthermore the presence of lead complexes in engine exhaust is considered objectionable by some. Therefore the removal of lead from gasoline might be desirable separate and apart from its characteristic of poisoning exhaust combustion catalysts. It has thus been heretofore proposed that lead free gasoline be supplied for use in automobiles equipped with emission control devices which utilize catalysts to help further oxidize exhaust gases.
Under most proposals, small, trace amounts of lead would be allowed in lead free gasoline. The Federal Government regulations require all gasoline sales outlets to furnish at least one grade of gasoline having less than 0.07 gram of lead per gallon to the public by July 1, 1974. On Feb. 23, 1972 the Environmental Protection Agency in a paper relating to the 1970 Clean Air Act Amendments offered for comment a requirement of 0.05 grams of lead per gallon of gasoline. The lead level reduction is to be accomplished by July 1, 1974. Other proposals have been even more stringent.
The normal network of petroleum product distribution involves railroad tank cars, pipelines, water borne tankers, tank trucks and bulk storage tanks. For commercial operation these are presently set up to handle different products. For example, the same pipeline might be used to convey a shipment of regular grade gasoline, premium grade gasoline, distillate fuel and other light liquid products in succession. According to present procedures, that portion of the fluids carried by the pipeline which constitutes an intermingling of the two products at their interface is diverted to use with the lower grade product, thus avoiding degradation of the higher grade hydrocarbon.
However when leaded gasoline is followed by leadfree gasoline, not just the interface comprising in intermingling of the two products, but the entire leadfree shipment becomes degraded. When leaded gasoline, containing tetraethyl lead, tetramethyl lead or a mixture of transalkylation products of the two is contacted with the metal or other surfaces of transportation and storage facilities, a significant amount of lead is left deposited in scale and on these surfaces. Since alkyl lead components are infinitely soluble in light hydrocarbons such as gasoline, upon after using the same faculties for lead free gasoline the latter product becomes contaminated with lead which may run as high as about 0.1 grams of lead per gallon or more. These amounts of lead are sufficient to impair the life of exhaust emission control oxidation catalysts and are in excess of the presently proposed allowable limits on lead content of lead free gasolines.
2. Description of the Prior Art Techniques have heretofore been known for removal of dissolved or suspended heavy metal contaminants from liquid products.
In catalytic cracking and reforming operations, the use of guard chambers containing a variety of sorbents and/or catalysts intended to remove heavy metal contaminants from the charge stock before contact is made with the catalyst have been described. Catalytic hydrodesulfurization processes and catalysts remove some amount of heavy metal contamination from hydrocarbon streams processed thereby.
Systems for removal of lead from gasoline have also been proposed. Presently known techniques require considerable time or are non-selective in effecting removal from the gasoline not only of the lead but also of those additives which are desired to be retained, such as antioxidants, anti-icing additives, metal passivators, detergents and the like.
I One previously proposed system for removing lead from gasoline is described in U.S. Pat. No. 2,368,261. There, acid activated clay, such as bentonite which had been previously treated with hydrochloric or sulfuric acid, is used. Leaded gasoline is percolated through the clay whereby up to percent of the lead present is removed. Unfortunately, acid activated clays will also remove other gasoline additives which are required or desired for proper protection and functioning of automo tive equipment.
Another approach is that described in US. Pat. No. 2,392,846. According to an Example in this patent, a five gallon lot of leaded gasoline is treated with 20 ml. of stannic chloride followed by addition of 100 grams of activated carbon. This results in decomposition of the tetraalkyl lead and adsorption of the lead decomposition products on the activated carbon thus drastically reducing the lead content. The gasoline is removed from the activated carbon by decantation. This is a very slow process which permits the processing of about 35 gallons of gasoline per hour. Unfortunately even in this system, the additives desired to be retained in the gasoline are also adsorbed by the activated carbon.
Both the processes described in the cited prior patents depend for effectiveness on a chemical conversion of the tetraalkyl lead. The lead compounds can be reacted with such materials as halogens, halogen acids, metal halides, metal salts, sulfur dioxide, carboxylic acids, metals in the presence of hydrogen etc. While alkyl leads are infinitely soluble in gasoline, the resulting decomposition products are not readily soluble in hydrocarbons and hence can be selectively adsorbed on high surface adsorbents.
The American Oil Company, in a paper presented at the May 9, 1972 meeting of the API Division of Refining noted that in a significant number of its stations it was presently unable to meet the 0.05 gram/gal. or even the 0.07 gram/gal. requirement using scrutinous control of their distribution system and segregation of products. The area of greatest potential contamination was that of the service station itself. The report would indicate that all gasoline manufacturers relying only on distribution control to ensure that the unleaded gasoline will remain within specifications, face an extremely difficult and expensive undertaking.
It is a primary objective of this invention to provide means to remove heavy metals from liquid, particularly hydrocarbon, streams. It is a further objective of this invention to remove lead alkyls from gasoline. It is an objective of this invention to selectively remove these metals from hydrocarbon streams by such means as will not remove gasoline additives, such as detergent additives, from gasoline streams. It is an objective of this invention to provide for means for removing lead alkyls from gasoline, such means being capable of regeneration. Other and additional objects of this invention will become apparent from a consideration of this entire specification including the claims and drawings.
SUMMARY OF THE INVENTION In accordance with and in fulfillment of the afore stated objectives, an embodiment of this invention consists of utilizing a sorbent comprising a porous solid substrate having pores with a minimum pore diameter of about A. and a minimum surface area of about 10 m /g; the substrate being modified by at least one functional group of an amine, alkyl halide or the like which acts as a bridging member between the substrate and at least one metal halide; mixed functional groups of amines or other weak Lewis bases with alkyl halides being particularly effective; the metal being a Group IB, IIB, IIIA, IVA, VA, VIA or VlIl metal having an atomic number of at least 13, for the removal of heavy metals from non-aqueous liquid solutions, and more particularly for removing lead'from gasoline. For purposes of this disclosure, the metal group designations referred to are as defined in Langes Handbook of Chemistry at 58-61 (10th ed. 1967). The gasoline is passed through said sorbent at a space velocity of up to 300 LHSV and a temperature of about -50C. to C.
Halides of the following metals work particularly well: iron (Fe), copper (Cu), silver (Ag), Zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), tin' (Sn), lead (Pb), phosphorous (P), arsenic (As), antimony (Sb), bismuth (Bi), sulfur (S), selenium (Se) and tellurium (Te). Those salts having a Lewis acid character exhibited unusually superior results.
The sorbents were prepared by a batch sorption technique in a manner which may be generally described as follows: 10cc of a metal halide such as tin chloride was added while stirring to approximately cc of a solvent such as acetone in a 500cc Erlenmeyer flask. To this mixture approximately 50cc of functionalized sorbent matrix was added. The flask was stoppered and the mixture was shaken occasionally over a period of about one half-hour. The mixture including the added matrix was then transferred 'to a chromatographic column and washed twice with approximately 5000 volumes of a solvent such as acetone. The sorbent was dried by passing P 0 dried nitrogen through the sorbent bed. An aliquot of the sorbent was swelled with the gasoline being used.
In a preferred embodiment, the metal salts of stannic chloride and/or antimony pentachloride bonded to a substrate having a surface area of at least 10 m /g. with pore diameter of at least lOA., through an amine bridging member produced an extraordinary ability to remove lead tetraethyl and tetramethyl compounds from gasoline. As illustrated by Table 7, described later in this disclosure in greater detail, a sorbent having a substrate of silica, a metal halide of stannic chloride bonded to the substrate by means of a tertiary amine reduced the lead concentration of gasoline from 0.36 g/gaL to 0.01 g/gal for 150 bed volumes of operation.
Furthefiniifl'a'sfiepict'd'inTible also described in greater detail later in this disclosure, the sorbent which comprises an embodiment of this invention removes lead moieties and other heavy metals selectively; important and needed additives such as cleansing detergents are not substantially removed.
While not wishing to be limited by a specific theory of operability, it is believed that the lead removal by the sorbents of this invention may be represented by the following notation:
ma rlx matrix matrix matrix matrix where X is a halogen and R is an alkyl. The above notation and the operation which it represents will be amplified later in the specification, and specifically in the section where the examples are described.
Another embodiment of this invention involves the method of regenerating a sorbent as previously described by means of acid extraction. In the preferred embodiment, a volume of sorbent which is spent, that is, no longer active for lead removal due to pro-- longed use, is washed sequentially withabout 15 volumes of benzene, methanol and water. Then about 25 volumes of about 20 percent hydrochloric (l-ICl) is passed over the sorbent. The sorbent is then washed free of acid and dried. The regenerated sorbent is then reactivated with a solution of the metal halide (a preferred sorbent is acetone) in a proportion of about 1:15 metal halide to sorbent as it is passed over the sorbent. Finally the regenerated sorbent is washed with volumes of solvent and air dried.
Other embodiments of this invention comprise the system and method of employing the previously described sorbent at any point in a system for distributing and dispensing motor fuels or in an automobile fuel system so as to substantially remove lead.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawings attached hereto represents a typical service station gasoline pump modified according to the present invention.
FIG. 2 is an enlarged view of the cartridge for containing the lead removal agent.
FIG. 3 is a view in fragmentary section of a cartridge for containing the lead removal agent.
FIG. 4 is an analytical curve illustrating amount of lead removal as a function of absorbance and transmittance.
FIGS. 5-8 are curves comparing turbidometric analysis with atomic absorption analysis for four selected sorbents.
FIG. 9 is a set of curves illustrating lead concentration as a function of volume of leaded gasoline treated.
FIG. 10 is a series of curves illustrating lead removed as a function of flow rate.
FIG. 11 is a curve illustrating lead content of effluent as a function of contact time.
FIG. 12 is a set of curves illustrating lead removal capacity as a function of contact time.
DESCRIPTION OF PREFERRED EMBODIMENTS In a preferred embodiment, the sorbent is placed in a canister in the discharge hose of a service station gasoline pump. This preferred embodiment is more particularly described by making reference to FIGS. 1-3.
As shown in FIG. I, a gasoline dispensing pump of conventional design includes a housing indicated generally at 10 within which are contained a motor driven pump and a metering device, not shown. The metering device drives, through suitable gearing, indicators within a panel 11 to report gasoline dispensed and price for the amount so dispensed. The fuel after passing through the metering device, is conducted to the outside of the housing through a pipe connection 12 and into a discharge hose 13 equipped with a valve nozzle 14.
The modification to conventional dispensing pumps is a canister 15 connected to the fuel discharge 12 by a pipe 16 provided with a valve for which the operating handle is shown at 17. Fuel from the pipe 16 is conducted to the top of canister 15 containing the lead removal agent from which it passes through a suitably prepared cartridge and is thence discharged to hose l3 and nozzle 14.
A typical cartridge isshown is FIG. 3 as constituted by a gauze container 18 within a wire mesh supporting cage 19. Disposed within the container gauze 18 is a mass of the lead removal agent of the type which characterizes this invention.
For the usual service station, a cartridge having a diameter of about 24 inches and length of about 12 inches should be adequate to reduce the lead content to acceptable levels for a working life of about one month. For stations having larger substantially lead free gasoline throughput, either the cartridge may be changed more often, or a larger cartridge may be installed between the fuel tank and the dispensing pump. (As previously noted, this disclosure contemplates utilizing the sorbent at any point in a system for distributing and dispensing motor fuels). Again referring to FIG. 2, when it is desired to change the cartridge, valve 17 is closed, the hose 13 is drained and the canister 15 is removed by unthreading from the top portion thereof. It is thus a simple matter to replace the cartridge in a very short period of time and return the dispensing pump to duty.
Applicant has discovered that performance of the previously described sorbent can be appreciably enhanced by the addition of an absorption material such as charcoal. Such an absorption or deliquesent material may either be mixed with sorbent particles contained in the canister 15 or be located upstream or downstream of the sorbent. When the absorption material is utilized to remove trace amounts of water in gasoline a preferred embodiment entails the location of the absorption material upstream of the sorbent.
EXAMPLES l-S such as acetone. The resin was dried by passing P 0 dried nitrogen through the resin bed.
These tests consisted of contacting approximately three to six volumes of gasoline containing 2.5 grams of lead/gallon gasoline with one volume of sorbent under ambient conditions, followed by a lead analysis of the contacted gasoline. The period of contact time is noted in the first 5 examples. (The lead analyses after 20 minutes, one hour and three hours roughly correspond to those found under flow conditions at space velocities of 9, 3 and 1 LHSV, respectively).
Following the contacting of the 2.5 grams of lead/gallon of gasoline fuel with the sorbent prepared as previously described, the lead content of the treated gasoline was analyzed as follows:
A 5 part by volume sample of gasoline was treated with 1 part by volume of a saturated solution of silver nitrate (AgNO in absolute ethanol. After standing for 10 minutes, the content of reduced silver in the sample was determined by turbidometric technique. These measurements were done at 425 nm or 500 nm depending on the gasoline used. The measured transmission was compared with a standard analytical curve similar to the one illustrated by FIG. 4. Results of examples 1-8 are illustrated by Table l.
.A.*. .TABLE t c o,
Metal sorbent removal Example designa- (percent number tion Sorbent complex Solvent Time Pb) Remarks 1 SB-(i CH3 ETOET 20 min. 90 1 hr 100 J- CHZIII- S1101;
.3 SB-S CH3 (CH3):CO 3 hr.66%
1 45 1 Wk.100% f CH2IYI-SHCI4 71 3 SB-9 /C (CHmCO Upto1wk 0 f-N -S nCl4 acrylic 4 SB-lO C (CHMCO 0 23 1 wk.100% f- O -C-N\ 95 l 0 Such 5 S B-ll (CHmCO min 0 1 wk.96%
f- CH'ZClSHCll 1 h 77 94 6 BI DEAE cellulose-SnCli 68 1 PR-65-A 0 o-Dichlorobenzene 1 hr 1'00 N -SnCl4 C --N S bCls 8 PR-65-B do 1hr 100 CH2C1- S bCls Comparison of example 3 with the other example results tabulated in Table 1 gives an indication of the importance of the substrate surface area. The acrylic substrate used in example 3 had a surface area substantially lower than the other substrates used, and as the results indicate, the lead removal ability of the sorbent formed with it was substantially lower than the other examples.
It is contemplated that substrates of the type described in this disclosure include spent cracking catalysts and inorganic oxides such as clays and pumice.
EXAMPLES 9-12 Metal halides having Lewis acid character were attached to various substrates as noted in Table 2. The table also indicates the solvent used during metal halide incorporation and the volume of gasoline passed over.
10 parts by volume of sorbent while still maintaining at least 50 percent removal of the initial lead at 11-13 LHSV.
The leaded gasoline to be treated was passed over the sorbent under the following continuous flow conditions:
The general procedure involved passing volumes of about 0.4 gram of lead/gallonof gasoline fuel through a 10 part by volume quantity of resin supported on a glass frit. The flow rates were controlled by varying the percent of stroke on a variable displacement pump, while a l to 2 part by volume gasoline hydraulic head was maintained above the resin by a fine adjustment stopcock.
The sorbents utilized in examples 9-12 were analyzed in a manner similar to the procedure described in examples 1-8.
TABLE 2.PERF0RMAN0E "OF VARIOUS METAL HALIDE REDISTRIBUTION Rfiii'di'zfi'rs" IN LEAD REMOVAL FROM GASOLINE Solvent used Sorbent during metal Example desig- Metal halide incor- Vl/Z cc./10 cc. number nation Sorbent B halide poration (sorbent) b 9 PR-SO SnCll Acetone 1, 200
J CH1(Cl)-9(CN)-1} E GDM 10 PR-34 Same as above SbCl Benzene 1, 400
ll PR-44 C SnCl; Acetone 1,600
C DVB 12 PR-48 Same as above SbCl Chloroform 2. 700
b Capacity at LHSV=10 king agent. EGDM=Ethylene glycol dimethacrylate. DVB=DivinylbenZene EXAMPLES 13-19 v A number of sorbents containing tin chloride (SnCl or antimony pentachloride (SnCl were analyzed for tin or antimony content before and after processing a gasoline of about 0.4 grams of Pb/gallon of fuel. The lead content of the used sorbents was also determined by chemical analysis, and the results summarized in Table 3. The gasoline flow conditions were identical to those described in the procedure recited in examples 9-12.
Those sorbents which efficiently removed lead and had large capacities in general showed little or no loss of tin or antimony to be processed gasoline. Lead removal by the sorbents in general paralleled the volume TABLE 3.TIN RETENTION AND LEAD PICKUP BY vxtirous soIWFKTsCONTAINWGsHtfiT" EXAMPLES 20-29 A class of sorbents with tin chloride in combination with active halogen was further modified by the addition of weak Lewis bases (nitriles). The relative concentration of halogen to nitrile; swelling of the sorbent after nitrile modifying treatment and stannic chloride addition; the weight percentage of tin incorporated with the sorbent; and the volume of gasoline passed over 10 volumes of the treated sorbent until 50 percent of the initial lead (0.4 gm/gal.) at 11-13 LHSV could no longer be removed were measured and summarized in Table 4. The gasoline flow conditions were identical to those described in the procedure recited in examples 9-12.
Volume of 0.33-0.39 g. Pb/gal. Weight percent gasoline Sorbent deleaded Example desig- Sn Sn 1 Pb l (ccJlO cc. nation Sorbent matrix initial final final sorbent) 13 $-11 J (3 H m .22 .07 .02 343 1 2 1 uvu\ 0 0n.u1 EGDM 15 SB-S C 11.4 12.2 .04 1,240
f G -o o1 ..(cN .1
1T PR-44 C 7.1 2.91 1.2 2,294
N DVB 18 PEI-46 OH 4.3 3.6 2.8 2,626
\l/ SiOz i C N N-C Wt. percent Sb w PR-48 o 14.0 14.6 .28 3,144
I All runs were terminated shortly alter the sorbent no longer removed 20% of the lead (-.4 gJgal.) at LSiIV=ll-l3.
" TABLE L sG'iiBENT JEFF'IFE'I'E'NGY o r SnCli 'iL'us'iEYiZiI'TIKLiDECONTAINING Pail MES Mole percent remaining of original swelling (Ace/gm.) Wt. Wt. -CHX percent Sorbent Base Cross percent After Sn+ Vol.1 Percent Ex. desigresin linking Cl in treat- After incor- LHSV- Sn efli- No. nation number agent Modifying treatment original CHz-Cl CHzCN merit SnCh porated 11-13 ciency 5 E (ge1). None 100 0 0 4 D -.d 11.2 2 E ..d 20.0 2 E KCN/HaO (58 C.) 16 hi 20.0 1 E NISGCIN/HQO (warm) 17.1 1r.
2 E KiI IY/DMSO (50 C.) 20.0
1r. 1 E 513-13 regenerated 20.0 2 E KSN/H O (40 C.) 20.0
r. 3 NaOH/HzO C.) 18.4
29...-. PR-33 2 E Sonlcated 125w 10mlm 20.0
E is ethylene glycol dimethylacrylete. D is dlvlnylbenzene. of gasoline processed in which 20 percent of the lead was removed. In example 18 nearly 3 percent by weight lead was incorporated into the sorbent. At such a high level of lead, its recovery by acid extraction would appear to be economically feasible.
EXAMPLES 30-35 The tin distribution in a number of sorbent matrices was determined by electron microprobe techniques; leaded gasoline was passed over a 10 part by volume sample of each sorbent until the sorbent was no longer &2 M RVEE E B Q Q 2230 now am ES $5 o 3632 2;.
952 S me? cm 328 2035a 23 we 555m $33 23 E EEEc 58.3mm" G E u 2A 2 mm B 2 w A III @5 5 338m 2. A E we 8 A n w &3? a 2552 am $62 3 M mm E 3 A 2 m E n E FEW .8 22m 82 Q8 NA 8m Q2 w m 32 I mm om om mm ow cm) I mmanbn oqmi QM 253mm E Q B A E Q B a E EwE E 53% axac gam a I 29.5 2553 m am m7 2 m m w m w 31m m 1 m m s m u 33 m mm vm mm a 3 mm I 35:55: ma ma zw a zm 25E -IIIIII.....I.II-I.II..I..... M 385m F :a I: g 5 3 5 w an 4 mm m6 #5 T: I 6% WWW W I I :nEm IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII I I w I N Q N N N w 832 W -4 $8 m6 m4 IIIIIIIIIIIIIIIIIIIIIIIIIIIIII II n 2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 4878 a 4. w w. .632 m SEE IIIIIIIIIIIIIIIIIIIIIIIII I I 4 oomA "5mg vnww whoa QGQOHQAH 3 m Ba m E A w w IIIIIIIIIIIIIIII I I fiwxuov 2:525 whom I. i. SI Q m mm IIIIIIIII Adiv flofio mfimflwQ w 33 3 258 SE 5 no I. Q! Q IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 315 3 I @535 Q 3 nV an my 32 IIIIIIIIIIIIII I I fiEubdc 38.5w 226mm SOUS m Q O O IIIIIIIIIIIIIIIIIIIIII 555 555w 0 2 z o Z; :u O I G ZO O :O l 210 5 O O 5 Q A 0 v no 0 I 0 E m m w: w w 21m 1 m w w IIIIIIIIIIIIIIIII noswzmmwoc 255w Nm 5 an mm 5 cm IIIIIIIIIIIIIIIIIII I I 5.: QEHEQ m Sm c885: 3:34
able to remove 50 percent of the initial lead concentra- EXAMPLE 47 tion (0.4 gm/gal) at 11-13 LHSV according to the flowing test procedure recited in examples 9-12; and A cyanide-treated chloromethylated polystyrene finally the lead distribution in the sorbent was deterresin (sorbent designating 58-13) which had been mined by microprobe techniques. The percent tin effi- 5 meted.with stannicvcllloridei-and whlch been ciency, that is the percent of the original tin which opdered mactve by Sansfactonly treatmg Over 200 erated to remove lead, was calculated tlqr each sorbent. umes of leaded gasoline grams/ was Table illustrates the physical propertie s orctiai'ac washed with portions of benzene, methanol and water. teristics of various sorbents all of which contained tin 250 volumes of 20 percent hydrochloric acid was then chloride (SnCl The table shows the amount of tin ed over the resin which was next washed with 250 initially f PP e sorbent, and the unifofvolumes water, methanol and finally air-dried. Two voly 0f the dlsmbution throughout the se V umes of stannic chloride in 30 volumes of acetone was EXAM S 36-3 then passed over the resin, followed by 100 volumes of Four sorbents were tested at LHSV 1 1-13 under the acetone; the resin was h d i d i j flowing test procedure recited in examples 9-12. Under This regenerated sorbent was again used to remove these conditions the lead removal was high generally lead from gasoline leaded to a 0.33-0.39 gm/gal. level.
above 80 percent. The treated gasoline was tested to determine its nitrogen component concentration to determine the amount of indigenous basic nitrogen compounds in gasoline removed during the lead removal EXAMPLES 5 rocess. A se arate anal sis of a deter ent additive was 2 made Rgsultslate i in Tablg 6t 7 A gasoline having a lead level of gram/gallon TABLE 6.THE EFFECT OF LEAD REMOVAL ON THE NITROGEN AND NITROGEN BASED DETERGENT CONTENT OF The results of the lead removal capability of the regenerated sorbent are plotted in FIG. 9.
GASOLINE Example number. 36 37 38 39 Sorbent designation. SIB-13 PR-44 PR-48 PR-46 C C O OH O C I l Substrate -Cll2(Cl) ,5(CN) .5 N N S102 Si-C-O-C-N-C-C-N C C O C Metal halide SnCl; SnCl; SbClg. SnClr Parts by Parts by N N volume fuel "N" volume fuel N" content Parts by volume fuel content processed content processed content Parts by volume fuel (p.p.m.) processed (co) (p.p.m.) (cc.) (p.p.m.) (cc.) (p.p.m.) processed (ca) 12 Original 13 Original 14 Original 14 Original 2. 0 375 4. 5 78 3. 6 80 3. 1 722 3.0 500 5. 7 1, 364 3. 5 1, 394 4. 2 1, 614 3. 0 870 6. 7 1, 918 5. l 2, 680 7. 9 2, 626 6.9 1,570 6.2 .034
No detergent removal N o detergent removal 33% detergent removal in 1st 400 cc.
in 1st 400 cc. in 1st 400 cc. (no removal after 400 cc.)
(a) Original content was 24#/1,000 bbl. or 3.6 p.p.m. N. 7) QeseslQga ts pyyo r egt sLaenmesywi texe e e at 11-13 LHSV- V m EXAMPLES 40-46 was diluted with a very low lead level gasoline until the Four sorbents, similar or identical to those tested in miXtUfeS a level as edaegd 9 10 g m/g llon. examples 36459 were tested at spaee Velocities g g Four sorbents were then tested at varying LHSV rangfrom 1 The sorbents tested pzlllsslng test procedure -150 bed volumes of leaded gaso me over eac recited in examples 9-12. The response of the low lead bent and measuring the lead content of the gasoline before and after treatment. The initial lead concentration was varied from Q10 to 039 grams of lead gallon the results at higher lead levels. The efficiency of sorof gasoline. The results of the test are shown in Table 50 bent designated as PR'44 was compared at two differ 7. s. en ..leeat !els( l3 gretaptlea laellon end 0,7 0
TABLE 7 Lead concentration, gJgal. Example Space Sorbent number velocity Feed Product O\(|)H C 40 12 .01 41 0 .01. slot Si N N smell 0 C 42 13 36 .16 43 11 10 .04 N SnCl 44 28 1O .02
o f@ N/ 5 46 13 39 11 f omol(cm Lend mmlysls after btlll volumes except as notod. A ter 7-5 tcd.voluulus.,.
eeeli ete $Pe9... .e. i yesie mxese it gram/gal). As noted in FIG. 7, the efficiencies were substantially identical.
The sorbent designated SB-13 was subjected to the gasoline flowing conditions recited in examples 9-12. The gasoline had a lead concentration of about 0.4 gm/gal, and the space velocity was varied from approximately 10 to 50 LHSV. The lead removal ability of the sorbent at the various space velocities was determined by atomic absorption analysis; the results are plotted in FIG. 11.
- EXAMPLE 53 EXAMPLE 54 The preparation of a silica based sorbent containing primary and secondary amine functional groups and attached stannic chloride is described below.
The xylene used as solvent in catalyst preparations was dried by azeotropic distillation using a Dean-Starkv trap. The silica used was Davison Grade 59 (properties of which are given in the table below) ground to 12/ 100 mesh and dried in a vacuum over at approximately 120C for about 4 hours.
Davison Grade 59 Silica Gel Silica Content (Dry Basis) 99.0% (Min.)
Total Volatile at 1750F 4.5% (Max.)
Apparent Density Approx. 25 lbs. per cubic foot Specific Heat 0.22 BTU/16F Surface Area 340 Sq. Meters/gm Pore Diameter (average) 140 Angstroms Pore Volume 1.15 CC/gm CHEMICAL ANALYSIS Typical (Dry Basis) Silica as SiO 99.50
Iron as Fe O; 0.01 Aluminum as A1 0.10 Titanium as TiO, 0.02 Calcium as CaO 0.07 Sodium -as Na,0 0.06 Zirconium as ZrO 0.03 Trace Elements 0.03
MOISTURE ADSORPTION Typical R.H 1.71 20% R.H. 2.88 40% R.H. 4.96 60% R.H. 7.80 80% R.H 16.96 100% R H 93.50
Approximately 150g silica suspended in about 750 ml. xylene was added 30.5g N-(B-aminoethyl) -'y-aminopropyltrirnethoxysilane. The mixture was stirred under reflux (about C) for approximately 4 hrs. and cooled. The liquid was decanted and the solid product was washed 3 times with about 400 ml. portions of n-hexane, stirred in hot distilled water for about hr. (to promote complete reaction and also remove unreacted silane) washed with water, and dried in a vacuum oven at about 130C for approximately 16 hr. This material contained about 4.50 wt.% C, 1.23 wt.% H and 1.1 wt.% N.
To about 60 cc. acetone in an approximately 250 cc. Erlenmeyer flask was added with stirring 4.0 cc. stannic chloride. Then about 20cc. of the above functionalized silica was added. The flask was stoppered and the mixture was shaken occasionally over a period of about '15 hour. The sorbent was then transferred to a chromatographic column and washed three times with about 2500. volumes of acetone. The sorbent was dried by passing P O -dried nitrogen through the sorbent bed.
The final product was designated PR-8l and contained 4.3 wt.% Sn.
EXAMPLE 55 The preparation of a silica based sorbent containing tertiary amine functional groups and attached stannic chloride is described below.
Approximately g. portion of the functionalized silane of Example 1 was suspended in about 250 ml. of 88 percent formic acid and about 185 ml. 37 percent formaldehyde and stirred under reflux -98C) for approximately 12 hr. After cooling, the liquid was decanted. The solid was washed 3 times with about 300 ml. distilled water, suspended in about 300 ml. distilled water and sufficient l N NaOH (-90 ml.) was added until the solution was neutral. The product was then filtered out, washed with about 300 ml. distilled water, stirred in about 700 ml. 90C distilled water for approximately 1 hr., filtered and dried in a vacuum oven at about C for approximately 16 hr. Analysis: 4.5%
.C, 1.23% H, 1.1% N. Tin chloride was incorporated in an identical manner to that of Example 1. The final product was designated PR-80 and contained 3.2 wt.% Sn.
EXAMPLES 5 6-5 7 TABLE 8 Sorbent Capacity (volumes of Example Designation gasoline/volume of sorbent 56 PR-80 425 57 PR-8l 480 EXAMPLES 58-59 The sorbents PR 80 and PR 81 were found to be more effective atelevated temperatures as shown in Table 9 where the instantaneous lead removal increased markedly on raising the temperature. The sorbents being studied were aged due to use and were op- 3. The method as claimed in claim 2 wherein said minimum pore diameter is about 10 A.
TRIKE 9 Capacity for more than 55% Sorbent Instantaneous Instantaneous Pb Removal l )esigna- Pb Removal Pb Removal at 55C tion Example at 25C at 55C (volumes/vol. of sorbent) PR 80 58 74% 94% 475 PR-8l 59 56% 87% 525 EXAMPLE 60 4. The method as claimed in claim 3 wherein said The sorbent containing primary amine functional groups designated PR-lOO was prepared as in Example 1 from antimony pentachloride and an aminopolystyrene resin containing 2.35 percent nitrogen. The sorbent was used to remove lead alkyl contaminants from gasoline containing 0.105 g. Pb/gal. The flow rate was 12 LI-ISV. Under these conditions the sorbent was effective in removing more than 55 percent of the lead alkyl from 230 volumes gasoline/volume sorbent.
EXAMPLE 61 The sorbent designated PR-9l was prepared in Example 54 from antimony pentachloride and the functionalized silica. The sorbent contained 8.37 percent antimony and was used to remove lead alkyl contaminants from a commercial gasoline containing 0.22g Pb/ gal. The flow rate was 12-48 LHSV and the temperature was 20C. Under these conditions the sorbent was effective in removing more than 5 5 percent of the lead alkyl from 380 volumes gasoline/volume sorbent. The gasoline detergent was not removed.
EXAMPLE 62 'y-Alumina having a surface area of about 200 M /g was functionalized as in Example 54 to give a product containing about 2.09% N.v This product was then treated with antimony pentachloride to give the sorbent (PR-l l 8) containing about 5.82% Sb. The sorbent was then used to remove lead alkyl contaminants from a gasoline blend containing about 0.0805 g. Pb/gal. The flow rate was approximately 12-24 LHSV. Under these conditions the sorbent was effective in removing over 50 percent of the lead alkyl from more than 600 volumes gasoline/volume sorbent.
What is claimed is:
l. A method for effecting removal of heavy metal contaminants from a substantially hydrocarbon solution containing the same which comprises contacting said solution with a sorbent for said metal contaminants comprising a substrate having a minimum surface area range of about m /g to 800 m /g and having pores with a minimum pore diameter range of about 10 A. to 500 A., said substrate being modified by at least one amine functional member, said substrate being further modified by at least one metal halide, the metal of said metal halide being a Group IB, IIB, IIIA, IVA, VA, VIA or VIII metal having an atomic number of at least 13, said functional member acting as a bridging member between said substrate and said metal halide; and removing said solution having a significantly lower heavy metal moiety concentration.
2. The method as claimed in claim 1 wherein said minimum surface area is about 10 mlg.
metal is selected from the group consisting of Fe, Cu, Ag, Zn, Cd, Hg, Al, Sn, Pb, P, As, Sb, Bi, S, Se and Te.
5. The method as claimed in claim 4 wherein said metal halides have Lewis acid character.
6. The method as claimed in claim 5 wherein said heavy metal contaminants are lead alkyl moieties said substantially hydrocarbon liquid solution is gasoline, and said contacting is carried out at about 50C. to C. and at space velocities of up to about 300 LHSV.
7. The method as claimed in claim 6 wherein said metal halide is tin tetrachloride.
8. The method as claimed in claim 6 wherein said metal halide is antimony pentachloride.
9. The method as claimed in claim 6 wherein said substrate is an oxide of at least one of the elements selected from the group consisting of B, Bi, Al, Si, Ga, Sn, Ti, Zr, V, Cr, Mo, W, Mg and Fe.
10. The method as claimed in claim 9 wherein said element is Al.
11. The method as claimed in claim 9 wherein said element is Si.
12. The method as claimed in claim 9 wherein said element is Ti.
13. The method as claimed in claim 9 wherein said sorbent is further modified by the addition of nitriles having weak Lewis base character.
14. The method as claimed in claim 11 wherein said oxide is SiO 15. The method as claimed in claim 14 wherein said amine functional member is a primary amine.
16. The method as claimed in claim 14 wherein said amine functional member is a secondary amine.
17. The method as claimed in claim 14 wherein said amine functional member is a tertiary amine.
18. The method as claimed in claim 17 wherein said tertiary amine is N,N,N'-trimethyl-'y-propyl ethylene diamine.
.19. The method as claimed in claim 18 wherein said metal halide is tin tetrachloride.
20. The method as claimed in claim 18 wherein said metal halide is antimony pentachloride.
21. In a process for distributing and dispensing motor 1 fuel comprising transportation means and storage means used alternatively for leaded and unleaded fuels and at least one substantially lead-free fuel dispensing station comprising storage means; pumping means; conduit means connecting said storage means and said pump; and conduit discharge means from said pump; the improvement which comprises contacting said fuel with a sorbent comprising a substrate having a minimum surface area range of about 10 m /g to 800 m /g and having pores with a minimum pore diameter range of about A. to 500 A., said substrate being modified by at least one amine functional group, said substrate being further modified by at least one metal halide the metal of said metal halide, being a Group 18, IIB, lIIA, IVA, VA, VIA or VllI metal having an atomic number of at least 13, said functional member acting as a bridging member between said substrate and said metal halide, said contacting being carried out at about 50C. to 100C. and at space velocities of up to about 300 LHSV; and removing said substantially lead-free gasoline.
22. The process as claimed in claim 21 wherein said minimum surface area is about 10 m /g.
23. The process as claimed in claim 22 wherein said minimum pore diameter is about 10 A.
24. The process as claimed in claim 23 wherein said metal halides have Lewis acid character.
25. The process as claimed in claim wherein said amine functional group is a primary amine.
26. The process as claimed in claim 20 wherein said amine functional group is a secondary amine.
27. The process as claimed in claim 20 wherein said amine functional group is a tertiary amine.
28. The process as claimed in claim 23 wherein said tertiary-amine is N,N',N'-trimethyl'y-propyl ethylene diamine.
29. The process as claimed in claim 28 wherein said metal halide is tin tetrachloride.
30. The system as claimed in claim 28 wherein said metal halide is antimony pentachloride.
31. The process as claimed in claim 28 wherein said sorbent is located in said pump discharge means so that said fuel passes through said sorbent as it is pumped.
32. The process as claimed in claim 31 wherein a absorption material is located upstream of said sorbent to effect water removal.
33. The method claimed in claim 1 wherein said method further comprises regenerating said sorbent by removing said metal contaminants by means of acid extraction, followed by adding a metal halide.
34. A method of regenerating a lead removal sorbent comprising a porous substrate bonded to a metal halide by means of an amine functional member, said method of regeneration comprising sequentially washing a spent sorbent, that is, one no longer active for lead removal due to prolonged use, with about 15 volumes of benzene, methanol and water; passing about 25 volumes of about 20 percent hydrochloric acid over said spent sorbent; washing sequentially said acid reacted sorbent with about fifteen volumes of 0.1 N NaOH and methanol; drying said sorbent; passing a metal halide over said sorbent in a proportion of about 1:5 metal halide to sorbent, said metal halide being in solution with a solvent in a proportion of about 1:15 metal halide to solvent as it is passed over the sorbent; washing said sorbent with about 10 volumes of solvent; and drying said sorbent.
3 3 I UNITED STATES PATENT OFFICE- CERTIFICATE OF CORRECTION Patent No. 3,793,185 Datgd February 19, 197 1- Inv n r(s) Darrell D. whitehurst, et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
(golumn ll In Table 5, pore volume of example number 32,
"1.15" should be --1.16--.
Column 19, "System" should be --process-.
line 29 si ned and sealed this 15th day of August 197 (SEAL) Attest:
MCCOY M. GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents