Abstract: A catalyst useful for hydroprocessing a hydrocarbon-containing oil contains at least one hydrogenation component on an amorphous, porous refractory oxide containing delta alumina. The catalyst is prepared by impregnating support particles having a narrow pore size distribution and a median pore diameter greater than about 185 angstroms with a solution containing a precursor of the hydrogenation components, followed by drying and calcining. The catalyst is useful for promoting a number of hydrocarbon hydroprocessing reactions, particularly hydrogenative desulfurization, demetallation and denitrogenation, and most particularly, hydrodemetallation of residuum-containing oils.

Abstract: An aromatic saturation process is catalyzed under relatively low pressure conditions in the presence of a halide-containing compound. Additive fluoride-containing compounds can be injected into the feedstock just prior to contact of the feedstock with either a fluoride or nonfluoride-containing catalyst. Also, a catalyst utilized in the invention contains Group VIB and/or Group VIII hydrogenation metals, phosphorus and fluoride supported on an amorphous, porous refractory oxide and has a narrow pore size distribution.

Abstract: A catalyst containing nickel, tungsten and phosphorus supported on an amorphous, porous refractory oxide having a narrow pore size distribution is utilized for converting hydrocarbon-containing feedstocks. The catalyst is particularly effective for promoting an aromatic saturation reaction.

Abstract: A process of preparing a catalyst for removal of sulfur and nitrogen in hydro-processing of hydrocarbon streams. The catalyst composition is formed by depositing molybdenum or tungsten. A second metal is deposited on the support layer in a non-aqueous fashion. The second metal being vandium, niobium or tantalum in organic solvent soluble metal alkoxide form. A third metal of nickel or cobalt is deposited and calcined on the support layer.

Abstract: A process for the catalytic hydrodesulfurization of hydrocarbon- containing feeds using a catalyst of a phosphorus component, a cobalt component and a Group VIB metal component on an alumina carrier.

Abstract: The hydrotreating of petroleum feedstock is improved by using a layered transition metal catalyst, a mixture of such catalysts or a stocked bed of transition metal catalysts that has a selected ratio of edge to rim sites sufficient to provide a product having a predetermined sulfur and nitrogen content.

Abstract: A premium coke is produced from a decant oil resulting from the catalytic cracking of petroleum oil by selectively hydrodesulfurizing the decant oil and then subjecting the hydrodesulfurized decant oil to delayed coking.

Abstract: A hydrocarbon conversion process to yield product of improved properties is effected in the presence of a zeolite characterized by increased Secondary Pore Volume, decreased Lattice Constant, Secondary Pore Mode, Secondary Pore Diameter, increased Secondary Pore Volume, Surface Silicon to Aluminum Atom Ratio, and Acid Site Density.

Abstract: A novel treated charge zeolite is prepared by treating charge zeolite (which is essentially free of Secondary Pores) with steam for 5-60 hours at 1000.degree. F.-1500.degree. F. Product is particularly characterized by increased Secondary Pore Volume (pores of diameter of 100A-600A) in amount of as high as 0.20 cc/g.

Abstract: The present invention relates to a spent hydroprocessing catalyst regeneration process wherein the catalyst is subjected to an initial partial decoking step, followed by impregnation with a Group VIB metal-containing component, and then subjected to a final decoking step.

Abstract: A catalyst composition useful in the hydroprocessing of a sulfur- and metal-containing hydrocarbon feedstock comprises 1.0-5.0 weight percent of an oxide of nickel or cobalt and 10.0-25.0 weight percent of an oxide of molybdenum, all supported on a porous alumina support in such a manner that the molybdenum gradient of the catalyst has a value of less than 6.0 and 15-30% of the nickel or cobalt contained in the catalyst is in an acid extractable form. The catalyst is further characterized by having a total surface area of 150-210 m.sup.2 /g, a total more volume of 0.50-0.75 cc/g, and a pore size distribution such that pores having diameters of less than 100A constitute less than 25.0%, pores having diameters of 100-160A constitute 70.0-85.0% and pores having diameters of greater than 250A constitutes 1.0-15.0% of the total pore volume of the catalyst.

Abstract: Heavy hydrocarbon oil, containing asphaltene, sulfur and metal contaminants, is hydrotreated in the presence of a hydrotreating catalyst having a small pore diameter in an initial process step to remove sulfur and metal contaminants. Removal of additional metal and sulfur contaminants is then accomplished in a second process step by solvent deasphalting, wherein the size of the pore diameter of the hydrotreating catalyst utilized in the initial hydrotreating step affects the metals rejection in the subsequent solvent deasphalting step. In a third process step the deasphalted oil is catalytically cracked substantially in the absence of added hydrogen to provide lower boiling hydrocarbon products.

Abstract: Disclosed is an improved process for the hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, and hydroconversion of a hydrocarbon feedstock containing asphaltenes, metals and Shell hot filtration solids precursors. The process utilizes a catalyst mixture wherein one component of the mixture is a relatively small pore catalyst and another component is a catalyst that possesses a relatively large amount of macropore volume.

Abstract: A dual component cracking catalyst system is disclosed comprising zeolite as a first component and a mixture of a calcium/magnesium-containing material and a magnesium-containing material as a second component. The preferred calcium/magnesium-containing material is dolomite and the preferred magnesium-containing material is sepiolite.

Abstract: For a heavy hydrocarbonaceous feed, especially good hydrodemetalation and hydrodesulfurization are achieved, as well as MCR reduction, using a catalyst having 5 to 11 percent of its pore volume in the form of macropores, and a surface area greater than 75 m.sup.2 /g. Preferably the catalyst has a peak mesopore diameter greater than 165 .ANG., as determined by mercury porosimetry, and an average mesopore diameter greater than 160 .ANG..

Abstract: Catalytic materials are modified by adding one or more electropositive and/or electronegative elements thereto in amounts sufficient to adjust the resultant geometric mean electronegativity to a value within a desired or predetermined range. The invention is particularly suited to the preparation of hydrocarbon hydroprocessing catalysts, particularly with respect to hydrodesulfurization catalysts comprising a support material containing a porous refractory oxide. With such catalysts, not only is the geometric mean electronegativity adjusted to a desired value, but if the electropositive or electronegative element added to the catalyst has pore growth promotion properties, the average pore size of the resultant catalyst is increased while its surface area, and usually also its total pore volume, is decreased.

Abstract: A catalyst useful for hydroprocessing a hydrocarbon-containing oil contains at least one hydrogenation component on an amorphous, porous refractory oxide. The catalyst is prepared by impregnating support particles having a narrow pore size distribution and a mode pore diameter from abpit 70 to 80 angstroms with a solution containing a precursor of the hydrogenation components, followed by drying and calcining. The catalyst is useful for promoting a number of hydrocarbon hydroprocessing reactions, particularly hydrogenative desulfurization, dedemetallization and denitrogenation, and most particularly, hydrodesulfurization of residuum-containing oils.

Abstract: A process for the hydrotreatment of a sulfur and metal-containing hydrocarbon feed comprises contacting said feed with hydrogen and a catalyst in a manner such that the catalyst is maintained at isothermal conditions and is exposed to a uniform quality of feed, where said catalyst has a composition comprising 3.0-5.0 wt. % of an oxide of a Group VIII metal, 14.5-24.0 wt. % of an oxide of a Group VIB metal and 0-2.0 wt. % of an oxide of phosphorus supported on a porous alumina support, and said catalyst is further characterized by having a total surface area of 150-210 m.sup.2 /g and a total pore volume of 0.50-0.75 cc/g with a pore diameter distribution such that micropores having diameters of 100-160A constitute 70-85% of the total pore volume of said catalyst and macropores having diameters of greater than 250A constitute 5.5-22.0% of the total pore volume of said catalyst.

Abstract: An improvement in a process which comprises feeding a heavy hydrocarbon oil and hydrogen to a fixed bed reactor which is charged with a demetallation catalyst at its upper stage and a hydrotreating catalyst at its lower stage, first contacting said feed stock with the demetallation catalyst under hydrotreating conditions and then contacting the same with the hydrotreating catalyst for the purpose of hydrotreating. The improvement comprises providing at the upper stage of the demetallation catalyst bed a small volume of a premetallation catalyst bed, said premetallation catalyst being lower in the activity than the demetallation catalyst. This predemetallation catalyst bed is charged with a catalyst which comprises one kind or more of metals selected from Group IIB, Group IVB, Group VB, Group VIB and Group VIII supported on a porous inorganic oxide carrier, said metals being 0.2 to 3 wt. % in terms of oxide, and has a pore volume of 0.4 to 1.5 ml/g and a void fraction of 55 vol % or more.

Abstract: The invention provides a nickel upon transition alumina catalyst containing 5-40% ww of nickel, with an active nickel surface area between 80 and 300 m.sup.2 /g of Ni, with a transition alumina that satisfies the following X-ray diffraction pattern:______________________________________ d (10.sup.-10 m) I/Io ______________________________________ 1.39 100 2.85 75-85 2.72 60-80 2.43 70 2.01 45-80 ______________________________________Preferably, the BET total surface area of the catalyst is between 50 and 200 m.sup.2 /g catalyst and is substantially free from pores with a radius below 2.0 nm.Also, a process is provided for hydrotreating unsaturated hydrocarbons, in which unsaturated hydrocarbons are treated with hydrogen in the presence of a catalyst as defined above.

Abstract: A two-stage catalytic hydroconversion process using a large-pore catalyst in the first stage reactor and a small-pore catalyst in the second stage reactor in the two-stage process for hydroconversion of coal or petroleum asphaltene feed materials to produce distillate liquid fuels. The large-pore catalyst is characterized by having pore diameters larger than 1000.ANG. occupying a major portion of the catalyst total pore volume of 0.2 to 1.0 cc/gm, and the small-pore catalyst is characterized by having pore diameters smaller than 1000.ANG. occupying a major portion of the catalyst total pore volume.

Abstract: The present invention relates to a process for the hydroconversion of heavy crude oil and an improved regenerable catalyst for use therein. The process broadly comprises (a) introducing into a hydroconversion reaction zone a feedstock of crude oil, hydrogen, from about 10 to about 1000 wppm of an active phase source selected from the group consisting of Group VB metals, Group VIB metals, Group VIIB metals, Group VIIIB metals, Group IA metals, Group IIA metals, and mixtures thereof, and from about 0.1 to about 20.0 wt. % of a refractory carrier material having a surface area in the range of from about 10 to about 700 m.sup.2 /g, a total pore volume of from about 0.1 to about 2.0 cm.sup.3 /g, an average pore diameter in the range of from about 20 to about 4,000 .ANG., a particle size diameter in the range of from about 1 to about 1000 .mu.m and a pore size distribution according to the following:______________________________________ Pores of radius r (.ANG.

Abstract: Hydrotreating catalyst composition comprising a hydrogenating component consisting essentially of a metal component in which the metal is selected from Group VIB and a phosphorus component, deposed on the surface of a support comprising a porous refractory inorganic oxide and free of zeolite component exhibits excellent hydrotreating activity and lifetime, particularly in the hydrodenitrogenation of high nitrogen feeds, e.g., whole shale oils or fractions thereof, and in the hydrodesulfurization and hydrodemetallation of high sulfur feeds, e.g., vacuum or atmospheric residual.

Abstract: A catalyst useful for hydroprocessing a hydrocarbon-containing oil contains at least one hydrogenation component on an amorphous, porous refractory oxide. The catalyst is prepared by impregnating support particles having a narrow pore size distribution and a mode pore diameter from about 70 to 80 angstroms with a solution containing a precursor of the hydrogenation components, followed by drying and calcining. The catalyst is useful for promoting a number of hydrocarbon hydroprocessing reactions, particularly hydrogenative desulfurization, dedemetallization and denitrogenation, and most particularyl, hydrodesulfurization of residuum-containing oils.

Abstract: This invention relates to hydrotreating with highly active hydrotreating catalysts prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, into a phosphated alumina hydrogel. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least about 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, and a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least about 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to hydrotreating with highly active hydrotreating catalysts prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into an alumina hydrogel. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least about 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to hydrotreating with highly active hydrotreating catalysts prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into an alumina hydrogel. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g, at least about 20% of the pore volume in pores having diameters greater than about 350 .ANG. and at least 20% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to hydrotreating with highly active catalysts prepared by incorporating from nickel and a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g and at least about 70% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: Hydrotreating with wide port-containing catalysts prepared by incorporating a metals solution containing an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, and an element selected from the group consisting of nickel, cobalt and mixtures thereof, into a phosphated alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, crush strengths greater than about 9 lbs and more than about 20% of their pores greater than 150 .ANG..

Abstract: A process for converting hydrocarbon oils into products of low average molecular weight and lower average boiling point comprising contacting a hydrocarbon oil at elevated temperature and pressure in the presence of hydrogen with a catalyst comprising a modified Y zeolite having a unit cell size below 24.45 .ANG., a degree of crystallinity which is at least retained at increasing SiO.sub.2 /Al.sub.2 O.sub.3 molar ratios, a water adsorption capacity (at 25.degree. C. and p/p.sub.o value of 0.2) of at least 8% by weight of modified zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm, an amorphous cracking component, a binder and at least one hydrogenation component of a Group VI metal and/or at least one hydrogenation component of a Group VIII metal. The invention also relates to catalyst compositions suitable for use in said process.

Abstract: Composition of matter suitable as a catalyst (base) in hydroprocessing comprising a crystalline aluminosilicate zeolite and a binder wherein the crystalline aluminosilicate comprises a modified Y zeolite having a unit cell size below 24.35 .ANG., a degree of crystallinity which is at least retained at increasing SiO.sub.2 /Al.sub.2 O.sub.3 molar ratios, a water adsorption capacity (at 25.degree. C. and a p/p.sub.o value of 0.2) of at least 8% by weight of modified zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm. The invention also relates to hydroconversion catalysts and processes based on said compositions of matter.

Abstract: A process for the hydrogenation of heavy oils, residual oils, waste oils, used oils, shell oils, and tar sand oils by hydrogenating a slurry of the oil at a partial hydrogen pressure of 50-300 bar, a temperature of 250.degree.-500.degree. C., a space velocity of 0.1-5 T/m.sup.3 h, and a gas/liquid ratio of 100-10000 Nm.sup.3/ T, wherein the additive comprises two different grain size portions, a fine grain portion having a grain size of 90 microns or less and a coarse grain portion having a grain size of 100-1000 microns.

Abstract: A hydroprocessing catalyst contains nickel, phosphorus and about 19 to about 21.5 weight percent of molybdenum (MoO.sub.3) components on a porous refractory oxide. The catalyst has a narrow pore size distribution wherein at least 75 percent of the pore volume is in pores of diameter from about 50 to about 110 angstroms, at least 10 percent of the pore volume in pores of diameter less than 70 angstroms and at least 60 percent of the pore volume in pores of diameter within about 20 angstroms above or below the average pore diameter. The catalyst is employed to hydroprocess a hydrocarbon oil, especially those oils containing sulfur and nitrogen components.

Abstract: Hydrotreating with catalysts prepared by incorporating cobalt and an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, into a phosphated alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, flat plate crush strengths greater than about 18 lbs and more than about 80% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: This invention relates to a method of preparing a metal-containing amorphous magnesia-alumina-aluminum phosphate catalyst support involving the admixture of an organic cation having a size equal to or greater than 2 Angstroms, the organic cation preferably being a tertiary or a tetraalkylammonium or phosphonium cation. The method permits recovery of a catalyst support having a controlled pore size distribution. The invention also relates to an improved catalytic support as well as an improved petroleum residua upgrading process comprising hydrotreating residua in the presence of the improved catalyst support.

Abstract: Hydrotreating with catalysts prepared by incorporating a metals solution containing cobalt and an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, into a phosphated alumina hydrogen support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, flat plate crush strengths greater than about 16 lbs and more than about 80% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: Hydrotreating with catalysts prepared by incorporating a metals solution containing nickel, an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into a phosphated alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, crush strengths greater than about 18 lbs and more than about 80% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: Hydrotreating with catalysts prepared by incorporating nickel, an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, and a stabilizing amount of phosphorus into a phosphated alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, crush strengths greater than about 18 lbs and more than about 80% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: A hydrotreating process comprises contacting a substantially liquid hydrocarbon-containing feed stream, which contains compounds of sulfur and metals (preferably Ni and/or V), in the presence of a fixed catalyst bed comprising at least one layer of substantially spherical alumina-containing particles which have been prepared by heating a specific starting material at about 500.degree.-900.degree. C. for improved crush strength retention. In a preferred embodiment, the fixed catalyst bed further comprises at least one layer (b) of catalyst particles comprising a refractory inorganic carrier and at least one hydrogenation promoter. A fixed catalyst bed comprising layers (a) and (b) is provided.

Abstract: This invention relates to a process for preparing highly active catalysts prepared by incorporating from nickel and a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof. The final calcined catalysts have surface areas at least about 300 m.sup.2 /g and at least about 70% of the pore volume in pores having diameters less than about 70 .ANG..

Abstract: A method for hydrotreating residual oil which comprises utilizing a hydrotreating catalyst which contains a thermally stable composition comprising a layered metal oxide containing an interspathic polymeric oxide having a d-spacing of at least about 10 angstroms at hydrotreating conditions. Said conditions include temperature ranging from about 357.degree. C. to 454.degree. C. (675.degree. F. to 850.degree. F.), a hydrogen partial pressure of at least about 2860 kPa (400 psig) and a liquid hourly space velocity ranging between about 0.1 and 10 hr.sup.-1.

Abstract: Hydrocarbon oils of which more than about 70% by volume boils above about 360.degree. C. and which have a C.sub.5 -asphaltenes content of more than about 2.5% by weight are contacted at elevated temperature and pressure in the presence of hydrogen with a supported molybdenum containing catalyst, in which process hydrocarbon oils containing substantial amounts of nickel are converted at a pressure of at least about 80 bar, using a supported molybdenum containing catalyst having an average pore diameter in the range of about 30 to about 80 nm.

Abstract: A hydrotreating process comprises contacting a substantially liquid hydrocarbon-containing feed stream, which contains compounds of sulfur and metals (preferably Ni and/or V), in the presence of a fixed catalyst bed comprising (a) at least one layer of impregnated substantially spherical alumina-containing particles which have been prepared by a process comprising the steps of impregnating specific starting material with at least one dissolved magnesium compound and then heating the thus impregnated material at about 500.degree.-900.degree. C. for improved crush strength retention. In a preferred embodiment, the fixed catalyst bed further comprises at least one layer (b) of catalyst particles comprising a refractory inorganic carrier and at least one hydrogenation promoter. A composition of matter comprising the impregnated, spherical alumina-containing particles described above, and a process for preparing them are also provided.

Abstract: A process for treating heavy hydrocarbon oil which contains metals and/or sulfur in the presence of a catalyst and recovering a hydrocarbon product having reduced metals and/or sulfur content by employing a metal impregnated mullite catalyst. The impreganted metals are selected from the group consisting of cobalt, nickel, molybdenum and tungsten. The mullite supporting bodies are prepared by calcining bodies of kaolin clay until the clay is converted to mullite and free silica, leaching the resulting bodies of mullite and silica with an alkaline aqueous solution to remove the silica, washing the leached clay bodies to remove alkali ions, and drying.

Abstract: A catalyst support is made with a bidisperse micropore size distribution. One region has small micropores with an average pore diameter of less than 100 Angstrom units. The other region has large micropores with an average pore diameter which is between 100 and 600 Angstrom units. By adding catalytic metals for desulfurization and demetallation, a hydrotreating catalyst is made which is able to treat heavy feeds containing large metal bearing molecules. In a preferred embodiment the desulfurization metals are placed in the small micropores and the demetallation metals are placed in the larger micropores.

Abstract: We provide reverse-graded catalyst systems which are capable of removing metals and sulfur from a hydrocarbon feedstock. They comprise two or more catalyst layers in which at least two successive catalyst layers characterized as having decreasing desulfurization activity, and increasing average macropore diameter in the direction of hydrocarbon flow. We also disclose a process for using them.

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incorporating a metals solution containing an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, an element selected from the group consisting of nickel, cobalt and mixtures thereof, and a stabilizing amount of phosphorus into an alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, crush strengths greater than about 20 lbs and more than about 80% of their pore volume in pores having diameters less than about 50 .ANG..

Abstract: This invention relates to a process for preparing highly active hydrotreating catalysts prepared by incorporating cobalt and an element selected from the group consisting of molybdenum, tungsten and mixtures thereof, into an alumina hydrogel support. The final calcined catalysts have surface areas greater than about 300 m.sup.2 /g, flat plate crush strengths greater than about 14 lbs and more than about 80% of their pore volume in pores having diameters less than about 70 .ANG..

Abstract: A composition of matter is prepared by a process comprising the steps of impregnating a alumina-containing support material with a thiocyanate (preferably ammonium thiocyanate), drying the thus impregnated material, impregnating the dried material with a transition metal compound, drying and calcining the transition metal impregnated material. This composition of matter is used as catalyst composition for hydrotreating of hydrocarbon-containing feed streams (in particular heavy oils) which contain metal and sulfur compounds as impurities.In another embodiment, a hydrotreating process comprises contacting hydrocarbon-containing feed stream (in particular heavy oils), which contains compounds of sulfur and metals, in the presence of a fixed catalyst bed comprising (X) at least one layer of impregnated substantially spherical alumina-containing particles which have been prepared by a process comprising the steps of impregnating specific starting material with NH.sub.