CA1102346A

CA1102346A - Process for producing a functionalized silica by reacting silica with a silane and a polyamine

Info

Publication number: CA1102346A
Application number: CA282,066A
Authority: CA
Inventors: Ian V. Howell; Ronald D. Hancock
Original assignee: BP PLC
Current assignee: BP PLC
Priority date: 1976-07-09
Filing date: 1977-07-05
Publication date: 1981-06-02
Also published as: AU2673177A; ZA774040B; GB1530039A

Abstract

ABSTRACT OF THE DISCLOSURE
A functionalised silica is prepared by reacting silica with a silane and a polyamine. The product is useful for removing metals from solution, e.g., Cu from ATX, or in the extraction of U from its ores.

Description

~ ~23~

The present invention relates to the removal of heavy metals, transition metals and actlnide metals from solution and in particular to the removal of copper, lead or uranium from solution, ~ s a res~lt of previous refining processes, traces of copper are sometimes present in distillate fuels such as automotive and aviation gasolines and aviation kerosines. Copper is undesirable because it is an oxidation catalyst which promotes the formation of gums and resins which affect the performance of an engine.
It is current practice to combat the adverse effect of copper by adding a copper deactivator to the fuel.
A further problem which is assuming increasing importance from the point of view of environmental protection is the removal of lead from automotive gasolines. As a result of pressure for - the reduction of lead levels, low lead and lead~free gasolines are becoming available, but these cannot be used in equipment previously used to convey or dispense gasoline with higher lead levels because of the risk of contamination unless the equipment is thoroughly cleaned, As a result of the growing demand for uranium as a nuclear fuel, the recovery of uranium from solutions produced in the hydrometallurgical processing of uranium bearing materials is also -~
of major importa~ceO
We have now discovered a material w~ich can be used for removing metals from solutions, Thus according to one aspect of the present invention there i~ provided a product, suitable for the removal of heavy metals, transition metals and actinida metals from solution, obtained by reacting an inorganio solid containing surface hydroxyl groups in a first stage with a compcund of formula (I) 3~

Y - Si - R - C~2 - X (l) whexein R i~ a divalent organic group containing up to 20 oarbon atoms, Rl and R are halogen atoms or organio radicals oontaining up to 20 carbon atoms, Y i8 a halogen atom or an -OR~ group in which ~3 repres0nts a H atom or an alkyl, aryl or acyl group containing up to 20 carbon atoms, and X i~ a halogen atom; and ~ ~
reacting the product of the first stage with a polyamine of general ~ ~ -formula (II) ~HR [ (CR 2~n NH ] m (CR 2)n NHR

wherein R4, R5, ~6 and R7 represent H atom~, alkyl or aryl group~
containing up to 20 oarbon atoms and may be the same of different7 n i9 an integer between l and 5, and m i~ an integer between l and 5, or a polyamine of formula (III) CH2 ~ \ ~CE _ (III) C~2 T2 CIH2 :

The inorganio solid containing surfaoe hydroxyl groups may be alumina, titania, zirconia, glass, sepiolite, or a zeolitic moleoular sieve. Preferably the inorganio solld is ~ilica and more preferably ~ilioa gel. In addition mixtures of inorganic ~olids may be u3ed. ~nle~s they have been sub~eoted to severe treatment~, e,g " heating above 1000C, all oommercial silioas contain ~urface hydroxyl group~. However for the removal of metal~
from alkaline media, under whioh condition~ ~ilica would be ohemioally attacked, it is prefer~ed to employ an alkali resistant inorganic ~olid containing surfaoe hydro~yl group~.

~23f~i R and R2 in the compound of formula (I) may be halogen atoms or alkyl, aryl, arylo~y or alkoxy radicals and may be the same or different. Preferably Rl and R are alkoxy or aryloxy groupe~ Preferably the group Y i9 an alkoxy group and the groups Rl and R2 and Y are identical alkoxy groups~
R in the compound of formula (I) i8 suitably an alkylene group containing up to 6 carbon atoms and i~ preferably a dimethylene group.
R4, R59 R and R7 are preferably H atoms, n is preferably

2 and m i9 preferably 1, 2 or 3.
In the case of 3ilica and the compound of formula (1) the substrate is believed to be formed by the reaction represented by the following equations-Rl Si - OH + Y - li - R - CH2 - X

- Si - - Si - R - CH2 - X ~ HY
R
~owsver the invention is not intended to be restricted in any way by the above ~quation repre~enting the formation of the ~ubstrate.
In the fir~t stage the reaction may be effected by warming the reactante together, e.g., t~tder reflt~ in the presence of an inert ~olvent for the compound of formula (I) for 1 to 3 hours and thereafter separating the product, A ~uitable solvent for the compound of formula (I) i~ toluene.
In the second st~ge, the reaction between the first stage product and the polyamine may take place in the absence or presence of a solvent, The reaction takes place at elevated te~perature, suitabl~ in the range 50-300C. Suitable solvents include ethers ~nd their derivativea 3uch as that sold under the Trade Name "Diglyme".

-- 4 ~

According to another aspect of the present invention there i~ provided a proce~s for the removal of heavy metal~, transition metals and actinide metal3 from 301ution, which process comprises contacting the solution with the 0econd s-tage reaction product as hereinbefore described and recovering an effluent of reduced metal content.
The term heavy metal within the context of th0 present application is intended to mean those metal~ in the B sub-groups of Group~ I to VI of the Periodic ~able according to Mendeleef.
The process is particularly applicable to the removal of the heavy metals copper and lead. ~ransition metal within the context of this application i0 defined a~ a metal which has an incomplete d-shell of electron3 in it~ electronic configuration. The term transition metal may be further sub-divided into non-noble transition metal~ e.g., manganese, iron and cobalt, and noble transition metals, which are transition metals generally con3idered to be highly reaiRtant to oxidation The term actinide metal i9 defined as a metal with an atomic number equal to or greater than B9 in the Periodic Table of Elements, It is clearly economically advanta~eous to operate at ambient temperature and in mo~t cases~ if not all, the product will function effectively at thi~ temperature, It will also remove metals at higher temperatures if the feedstock is ~upplied at elev~ated temperature.
~he BubBtrate i3 thought to remove the metal~ by complex compound formation throu~h the donor ligands bonded to the inorganic surface, Wh0n the substrate loses its activity for removing metals it may either be disposed of without removing the metals or the metals may be removed by means known to those skilled in the art.
One such method for removing the metal from tha sub~trate is to ¢ontact the metal loaded ~ubstrate with an aqueous 001ution of a

3~;

mineral acid followed by separa-tion of the aqueous solution containing the metal from the substrate. The mineral acid should be chosen so that the resultirlg me-tal salt is soluble in the treating solution.
Thus for example9 hydrochloric acid is suitable for copper removal but not for lead. Nitric acid shou~d be employed for the latter.
Thereafter the metal may, if desired, be recovered from the aqueous solution by methods well known in the art.
~ he solution containing metals may be contacted with the substrate batchwise, or9 preferably continuously by passing the solution over a bed of the substrate mounted in a suitable reactor, The invention is illustrated by the following Examples:-Example 1 ane with Silica Acid washed silica gel (lOO g) was suspended in toluene (500 ml) and distilled water (50 ml) added. ~he mixture was stirred at room temperature for 2 hours and then warmed to reflux. The residual water was distilled from the reaction flask and collected in a Dean and Stark receiver, which was periodically drained, After cooling to room temperature ~-chloropropyl trimethoxy silane (100 ml) was added to the fla~k and the mixture stirred and warmed to reflux for 3 hours. ~he methanol liberated was distilled off and collected in a Dean and Stark receiver, which again was periodically drained. After cooling the silica was transferred to a Soxhlet apparatus, extracted with methanol for 24 hours and finally dried in vacuo.
On analysis the silica product contained 1.55 per cant weight chlorine.
Example 2 The ohloro-silica (20 g) prepared as described in ~xample l, 23~6 was added to triethylene tetramine (lOO ml) contained in a 250 ml flask under an atmosphere of dry ni-trogen The mixture was stirred and warmed to 195 - 198 C for 24 hours. After cooling to room temperature, the residual liquid was decanted and the silica transferred to a Soxhlet apparatus. Soxhlet extraction using dry methanol under a nitrogen atmosphere was maintained for 18 hours, the silica finally being dried in vacuo.
On analysis the product contained 1.96 per cant weight nitrogen.

Reaction_of Chloro-silica with Tetraethylene Pentamine Tetraethylene pentamine (100 ml) was added to the ohloro-silica (20 g) prepared as described in Example 17 and contained in a 250 ml flask under an atmosphere of dry nitrogen. The mixture ~-was stirred and warmed to 195 - 200C for 24 hours. After cooling to room temperature, the silica was transferred to a Soxhlet apparatus was finallg dried in vacuo.
On analysls the product oontained 2.28 per cent weight nitrogen.
~ .
Reaction of_Chloro-silica with 2?Z~2"-triaminotrieth ~amine The chloro~silica (20 g) prepared as described in Example 19 was suspended in Diglyme (75 ml) under a nitrogen atmosphere.
2,2',2"-triaminotriethylamine (20 ml) was added and the mixture stirred and heated to reflux temperature for 24 hours~ After cooling, the silioa was transferred to a Soxhlet apparatus, extracted with methanol for 24 hours and finally dried in vacuo.
On analysis the product oontained 1,50 per oent weight nitrogen.

Conoentrated Jet A-1 Aviation Spirit oontaining 170 ppb of soluble oopper was pumped at a liquid hourly spaoe velocity of 11~239L6 9,7 - lO,l and at ambient temperature and pressure, over a flxed bed of amino-silica (2 ml), prepared as described in Example 2, which was contained in a glass microreactor. Hourly product samples were collected and analysed for copper content Analysis showed that the copper content of the product samples was 25 ppb for the 7-hour duration of the test.
am~le 6 Concentrated Jet A-l Aviation Spirit containing 120 ppb of soluble copper was pumped at ~ liquid hourly space velocity of lO, and at ambient temperature and pressure, over a fixed bed of amino-silica (2 ml~, prepared as described in Example 3, which was contained in a glass micro-reactor. Hourly product sa~ples were collected and analysed for copper content. Analysis showed that the copper content of the product samples was 20 ppb for the 7-hour duration of the test.
Example~
Concentrated Jet A-l Aviation Spirit containing 170 ppb of soluble copper was pumped over the amino-silica (2 ml), prepared aq described in Example 4, and using the same conditions as de3cribed in Example 6, Analysis of the hourly product samples showed that the copper oontent was 25 ppb for the 7-hour duration of the test.

A solution of anhydrous ferrous chloride dissolved in acetone was added to an acetone su~pension of a N-alkyl-triethylene tetramine ligand-~ilica, prepared as described in Example 2, under an atmosphere of dry, dsoxygenated nitrogen. After stirring the reaction mixture for 2 hours at room temperature the silica was isolated by filtration.

Any residual f0rrous chloride was removed by washing the silica with acetone, acetone oontaining a few drops of n-butyric acid and 3~6 finally acetone again. The produce was finally dried in vacuo.
On analysis the silica contained 1.27 per cen-t weig~ht iron, A solution of ferrous sulphate acidified to a pH of approximately 2 with diLute ~ulphuric acid, was added to a N-alkyl-triethylene tetramine ligand-silica and the mixture stirred for 2 hours at room temperature, under a nitrogen atmo phere The silica was filtered off, washed free of any residual ferrous sulphate with very dilute sulphuric acid, then water and finally acetone. 'rhe product was finally dried in vacuo. On analysis the silica contained loO9 per cent weight iron.

A solution of anhydrous ferrous chloride dissolved in acetone wa3 added to an acetone suspension of a N-alkyl-tetraethylene pentamine ligand-silica, prepared as described in Example 3~ under an atmosphere of dry, deoxygenated nitrogen. After stirring the reaction mixture for 2 hours at room temperature the silica was isolated by filtrætion. The silica ~la~ freed from any residual ferrous chloride by washing with acetone7 then acetone containing a few drops of n-butyrio acid, and finally acetone again. The product was finally dried in vacuo. On analysis the silica was found to contain 0 54 per cent weight iron.
~a~ :
A solution of anhydrou~ ferrous chloride dissolved in acetone was added to an acetone suspension of a N-alkyl-2,2~,2";triaminotriethylamine ligand-silica, prepared as deccribed in Example 4, and the reaction mixture stirred for 2 hours at room temperature under an atmosphere of dry, deoxygenated nitrogen. ~he silica was isolated by filtrationt washed free from any re~idual ferrous chloride with acetone, acetone containing a few drops of n-bu~yric acid and finally acetone again.

2~4~

The silica was finally dried in vacuo. On analysi6 the product was fo~md to contain 0.19 per cent waight iron.
~1~ .
250 ml of an aqueous solution of uranyl nitrate containing .79 K of Uo2(No3)26X2o was stirred with 1.59 g of the triethylene tetramine functionalised ~ilica, prepared as described in Example 27 for 4 hours at room temperature. After allowing the mixture to stand for 26 hours the silica product was transferred to a Soxhlet appaxatu6 and extracted with water for 8 hours, followed by methanol for 24 hours. ~he silica was finally dried in vacuo. On analysis the silica was found to contain 3.1 per cent weight uranium.
~ . .
200 ml of a dilute sulphuric acid solution of uranyl sulphate containing 1.69 g of U02S04~H20 was stirred with 1.39 g of lhe triethylene tetramine functionalised silica, prepared as described in Example 2, for 5 hours at room temperature. After allowing the mixture to stand for 18 hours the silica product was transferred to a So~hlet apparatus and extractcd with water for 18 hours followed by methanol for 8 hours, The silica was finally dried in vacuo. On analysi~ the silica was found to contain 0.9 per cent weight uranium.

200 ml of a dilute sulphurio ac1d solution of uranyl sulphate containing 1.29 ~ U02S043~20 was stirred with 2.11 g of the acid w~shed U30 silica ba~e for 5 hour~ at room temperature. After allowi the ~ixture to stand for 18 hours the silica product was transferred to a ~oxhlet apparatus and e~tracted with water for 18 hours followed by methanol for 8 hours, ~he silica was finally dried in vacuo.
~n analy~is the ~ilica was found to contain 0.1 per cent weight uranium.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A product, suitable for the removal of heavy metals, transition metals and actinide metals from solution, obtained by reacting an inorganic solid containing surface hydroxyl groups in a first stage with a compound of formula (I) (I) wherein R is a divalent organic group containing up to 20 carbon atoms, R1 and R2 are halogen atoms or organic radicals, Y is a halogen atom or an - OR3 group in which R3 represents a H atom or an alkyl, aryl, or acyl group containing up to 20 carbon atoms and X is a halogen atom; and reacting the product of the first stage with a polyamine of formula (II) (II) wherein R4, R5, R6 and R7 represent H atoms, alkyl or aryl groups containing up to 20 carbon atoms and may be the same or different, n is an integer between 1 and 5, and m is an integer between 1 and 5, or a polyamine of formula (III).

(III)

2, A product according to claim 1 wherein the inorganic solid containing surface hydroxyl groups is alumina, titania, zirconia, glass/ sepiolite or a zeolitic molecular sieve.

3. A product according to claim 1 wherein the inorganic solid containing surface hydroxyl groups is silica.

4. A product according to claims 1, 2 or 3 wherein R1 and R2 are alkoxy or aryloxy groups.

5. A product according to claims 1, 2 or 3 wherein Y
is an alkoxy group.

6. A product according to claims 1, 2 or 3 wherein R
is an alkylene group containing up to 6 carbon atoms.

7. A product according to claims 1, 2 or 3 wherein R4, R5, R6 and R7 are H atoms.

8. A product according to claims 1, 2 or 3 wherein n is 2 and m is 1, 2 or 3.

9. A process for the removal of heavy metals, transition metals and actinide metals from solution by contacting the solution with a product according to claims 1, 2 or 3.