Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2001-03-13
2004-05-25
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C208S203000
Reexamination Certificate
active
06740619
ABSTRACT:
The present invention relates to an improved process for the preparation of a catalyst useful for liquid-liquid sweetening of LPG and light petroleum distillates.
More particularly the invention relates to the preparation of sulphonamides of various metal phthalocyanines suitable as catalysts and their use for liquid-liquid sweetening of pentanes, LSRN, cracked naphtha and regeneration of alkali in the extraction of mercaptans from LPG, pentanes, LSRN and light thermally cracked naphtha.
It is well known that the presence of mercaptans in the petroleum products like LPG, naphtha, gasoline, kerosene, ATF etc is highly undesirable because of their foul odour and highly corrosive nature. They are also poisonous to the catalysts and adversely affect the performance of tetraethyl lead as octane booster. Although there are several processes known for the removal of mercaptans from petroleum products, the most common practice is to oxidize the mercaptans present to less deleterious disulphides with air in the presence of a catalyst. Generally, the lower mercaptans present in LPG, pentanes, LSRN and light thermally cracked naphtha are first extracted in alkali solution and then oxidized to disulfides with air in the presence of a catalyst. The disulphides, being insoluble in alkali solution, separate out from the top and the alkali is regenerated. In the liquid-liquid sweetening the lower mercaptans present in petroleum products like pentanes, LSRN, cracked naphtha etc are converted to disulphides by direct oxidation with air in the presence of alkali solution and catalyst. The higher molecular weight mercaptans present in petroleum products like heavy naphtha, FCC gasoline, ATF and kerosene are oxidized to disulphides with air in a fixed bed reactor containing catalyst impregnated on a suitable support like activated carbon (Catal. Rev.-Sci. Eng. 35(4), 571-609 (1993).
It is also well known that the phthalocyanines of the metals like cobalt, iron, manganese, molybdenum and vanadium catalyze the oxidation of mercaptans to disulphides in alkaline medium. Among these cobalt and vanadium phthalocyanines are preferred. As the metal phthalocyanines (MPC's) are not soluble in aqueous medium, for improved catalytic activity their derivatives like sulphonated and carboxylated metal phthalocyanines are used as catalysts for sweetening of petroleum fractions. For example use of cobalt phthalocyanine monosulphonate as the catalyst in the fixed bed sweetening of various petroleum products (U.S. Pat. Nos. 3,371,031; 4,009,120; 4,207,173; 4,028,269; 4,087,378; 4,141,819, 4,121,998; 4,124,494; 4,124,531) and cobalt phthalocyanine disulphonate (U.S. Pat. No. 4,250,022) tetra sulphonate (U.S. Pat. No. 2,622,763) and the mixture thereof (U.S. Pat. No. 4,248,694) as catalysts for liquid-liquid sweetening and alkali regeneration in mercaptan extraction of light petroleum distillates have been reported. The use of phenoxy substituted cobalt phthalocyanine as sweetening catalyst (Ger Offen 3,816,952), cobalt and vanadium chelates of 2,9,16,23-tetrakis (3,4-dicarboxybenzoyl)phthalocyanine as effective catalyst for both homogeneous and fixed bed mercaptan oxidation (Ger Offen 2,757,476; Fr. Demande 2,375,201) and cobalt, vanadium chelates of tetrapyridinoporphyrazine as active catalysts for sweetening of sour petroleum distillates (Ger offen 2,441,648) have also been reported.
It is well known that the catalysts used for the liquid-liquid sweetening of petroleum fractions like pentanes, LSRN, etc. and regeneration of alkali in the mercaptan extraction from LPG, pentanes etc are di-, tri-and tetra sulphonates of metal phthalocyanines particularly those of cobalt and vanadium phthalocyanines; cobalt phthalocyanine sulphonates being specially preferred. The cobalt phthalocyanine sulphonates differ in activity and in their solubility characteristics depending upon the number of sulphonate functionalities leading to problems in their use as catalysts.
Cobalt phthalocyanine disulphonate, a commonly used catalyst in liquid-liquid sweetening and alkali regeneration, is extremely dusty in the dry fine powder form and causes a handling problem. To overcome this problem cobalt phthalocyanine disulphonate is admixed with water and commonly used as a slurry. However, with insufficient mixing the cobalt phthalocyanine disulphonate precipitates out from the slurry. Moreover, even if the slurry is mixed sufficiently, it retains the cobalt phthalocyanine disulphonate in suspension for a particular length of time only, beyond which the slurry becomes extremely viscous and may form gel, making it very difficult to remove the material from packaging. Cobalt phthalocyanine tetrasulphonate, on the other hand, is highly soluble in water and its use can eliminate precipitation and gel forming problems associated with the use of cobalt phthalocyanine disulphonate. However, it is reported that cobalt phthalocyanine tetrasulphonate has lower catalytic activity than cobalt phthalocyanine disulphonate (U.S. Pat. No. 4,885,268). Further, preparation of the metal phthalocyanine disulphonates by reacting metal phthalocynines with oleum has handling and working-up problems.
During our investigations on the development of new sweetening catalysts, we observed metal phthalocyanine sulphonamides to be active catalysts for liquid liquid sweetening of light petroleum products (Indian Patent No 1,53,190, Indian
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Patent No. 1,52,541 and Ind. J. Tech. 25, 397-400 (1987)). In these patents and literature a procedure for making cobalt phthalocyanine sulphonamides has been reported. This method involves treatment of cobalt phthalocyanine with chlorosulphonic acid followed by amidation with ammonia gas. However, the catalyst yield and activity was found to be low. Hence the present invention provides an improved process for the preparation of metal phthalocyanine sulphonamides in considerably higher yields and with very high catalytic activities for both liquid-liquid sweetening and alkali regeneration.
The objective of the present invention is to provide an improved process for the
15
preparation of metal phthalocyanine sulphonamide suitable a catalyst for liquid-liquid sweetening of pentanes, LSRN, cracked naphtha etc. and regeneration of alkali in the mercaptan extraction from LPG, pentanes, LSRN, light thermally cracked naphtha and the like, which obviates the drawbacks as detailed above.
Accordingly the present invention provides an improved process for the preparation of catalyst metal phthalocyanine sulphonamide of the formula
Mpc(SO
2
NHR)
x
wherein MPc represents
M is Co, Ni, Fe, Mn, Cr or V;
X is 1, 2, 3 or 4 and
R is hydrogen, alkyl,or cycloalkyl,
useful for LPG and light petroleum distillates which comprises;
reacting a metal phthalocyanine with chlorosulphonic acid at a temperature in the range of 90-150° C. for a period ranging between 1 hr-5 hrs, cooling the mixture to a temperature ranging between 40-80° C., adding 1-7 parts of a chloride reagent to the said mixture, heating the above said mixture to a temperature ranging between 60-80° C for a period ranging between 0.5 hr to 3 hrs to obtain the metal phthalocyanine sulphonyl chloride, isolating the above said compound by adding the reaction mixturein an ice cold water, reacting the above isolated metal phthalocyanine sulphonyl chloride with an amine of general formula H
2
NR where R is selected from hydrogen, aryl, alkyl and cycloalkyl in an aqueous or non aqueous medium or a mixture thereof at a temperature in the range −4 to 15° C. and at a pH ranging between 7-9 in the presence of an acid binding agent to obtain the desired catalyst.
In an another embodiment of the present invention the metal phthalocyanine used is selected from the group consisting of cobalt, manganese, iron, nickel, chromium and vanadium phthalocyanine, most preferably cobalt phthalocyanine.
In yet another embodiment of the present invention the chloride reagent used is selected from thionyl chloride, phosphorus trichloride and phosphorus pentachloride.
In yet another embodiment of the pre
Balodi Bhagwati Prasad
Bhatia Virendra Kumar
Das Gautam
Kapoor Virendra Kumar
Kumar Anil
Bell Mark L.
Brown Jennine M.
Council of Scientific and Industrial Research
Ladas & Parry
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