Abstract:
In the process of converting an aromatic feedstock to an alkyl-substituted mono-nuclear aromatic product by contacting the feedstock with a coke-selectivated ZSM-5 type catalyst at elevated temperature under conversion process coking conditions to produce said alkyl-1-substituted mononuclear aromatic product selectively, the improvement which comprises:regenerating the process coked catalyst in contact with a non-oxidizing atmosphere comprising an effective amount of hydrogen at a temperature of about 800.degree. F. to 1200.degree. F. to restore activity of the catalyst while retaining selectivity. Advantageously, the conversion involves alkylation, disproportionation and/or isomerization to produce at least one lower alkyl or dialkyl benzene product.
Abstract:
The present invention relates to a new method for preparing a composition comprised of a crystalline zeolite having deposited thereon a coating of silica which extensively covers and resides substantially exclusively on the external surface thereof, and to the composition so prepared.
Abstract:
Living plants and animals synthesize and often accumulate a wide variety of organic materials having a molecular weight greater than 150. These include different chemical types such as natural hydrocarbons including rubbery substances, natural resins, and natural glycerides such as oils and fats. These substances, formed in the anabolic process, are collectively called "anabolites".This invention provides a process for catalytically converting certain anabolites to liquid hydrocarbons useful for the manufacture of fuels such as gasoline and chemicals such as para-xylene. Crystalline aluminosilicate zeolites having an effective pore size of greater than about 5 Angstrom units are useful catalysts.
Abstract:
A process is provided for the selective production of para dialkyl substituted benzenes wherein the alkyl group contains from 1 to 4 carbon atoms which comprises contacting, under conversion conditions, a hydrocarbon precursor selected from the group consisting of mono alkyl-substituted benzenes having 1-4 carbon atoms in the alkyl substituent and a mixture of said precursor or benzene with an alkylating agent containing from 1 to 4 carbon atoms with a catalyst comprising a porous crystalline aluminosilicate zeolite having deposited thereon a coating of silica which extensively covers and resides substantially exclusively on the external surface thereof, said zeolite being characterized by an activity, in terms of alpha value, of between about 2 and about 5000, a xylene sorption capacity greater than 1 gram/100 grams of zeolite and an ortho xylene sorption time for 30 percent of said capacity greater than 10 minutes, said sorption capacity and sorption time being measured at 120.degree. C and a pressure of 4.5 .+-. 0.8 mm. of mercury and recovering from the resulting product mixture, a para dialkyl substituted benzene in an amount greater than the thermodynamic equilibrium concentration thereof in the total dialkyl substituted benzenes produced.
Abstract:
A catalyst is provided, which is especially applicable for the selective production of C.sub.2 -C.sub.3 olefins, comprising a crystalline aluminosilicate zeolite having a silica to alumina ratio of at least about 12, a constraint index, as hereinafter defined, within the approximate range of 1 to 12 and having contained within the interior crystalline structure thereof added amorphous silica in an amount of at least about 0.3 and preferably between about 0.5 and about 30 weight percent. The resultant catalyst is characterized by n-hexane sorption capacity at a temperature of 90.degree. C and a n-hexane partial pressure of 83 mm. of mercury which is at least 1 percent less than corresponding sorption capacity under identical conditions for the unmodified zeolite. Generally, the n-hexane sorption capacity for the described silica-modified zeolite, at the above specified conditions, is 5 to 60 percent less than that for the zeolite which has not undergone treatment to incorporate amorphous silica therein. The invention described herein also encompasses synthesis of the specified catalyst and use of the same in selectively converting lower monohydric alcohols and their ethers, especially methanol and dimethyl ether, to a hydrocarbon mixture rich in ethylene and propylene.
Abstract:
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.
Abstract:
A method of preparing a modified catalytic molecular sieve for enhanced shape selective hydrocarbon conversions in which a catalytic molecular sieve is modified by being exposed to at least one ex situ selectivation sequence, each sequence including an impregnation of the molecular sieve with a selectivating agent in an aqueous emulsion and a subsequent calcination of the impregnated molecular sieve. The selectivating agent compositions for the ex situ selectivation method are also described, including the selectivating agents, the surfactants, and the aqueous components. Also, a method for moderate steaming of the ex situ selectivated molecular sieve. Also a method for in situ trim-selectivating the ex situ selectivated catalytic molecular sieve. Also described is the modified catalytic molecular sieve modified by this method. Also described is a process for shape selective hydrocarbon conversion comprising contacting a hydrocarbon feedstream under conversion conditions with the modified catalytic molecular sieve.
Abstract:
A process for a shape selective hydrocarbon conversion such as toluene disproportionation involves contacting a reaction stream under conversion conditions with a catalytic molecular sieve which has been pre-selectivated and concurrently activated by contact with a substantially aqueous solution of an organosilicon compound. The invention also includes a method for concurrently preselectivating and activating a catalyst and the shape selectivated, activated catalyst which results from this method.
Abstract:
There is provided a process for oligomerizing propylene by contacting propylene with silica modified zeolites. The modification of the zeolite with silica results in a product which is enriched in hydrocarbons falling within the boiling range of jet fuel (330.degree.-480.degree. F.) and diesel fuel (480.degree.-650.degree. F.). The zeolite may be ZSM-5, which may be modified by sorbing methylhydrogensilicone into the pores of the zeolite followed by calcination to convert the sorbed methylhydrogensilicone into amorphous silica.
Abstract:
Oligomers produced from lower alkenes by acidic zeolite catalyzed oligomerization can be converted to useful lubricant additives or lubricants by amidation and sulfonation of olefinic bonds in the oligomers by reaction with nitriles in the presence of strong acid catalyst whereby oligomer derivatives containing amide groups and sulfonic acid groups are produced. The products so produced from C.sub.20 + olefins exhibit favorable qualities as lubricants. The discovery is particularly applicable to the amidation and sulfonation of oligomers produced from lower olefins such as propylene by oligomerization using a ZSM-5 catalyst which has been surface deactivated.