126-98-7

Radical-ion salts bis(biphenyl)chromium(i) 1,4-di(2-cyanoisopropyl)-1,4- dihydrofulleride [(Ph2)2Cr]+?[1,4- (CMe2CN)2C60]-? and bis(biphenyl)chromium(i) 1-(2-cyanoisopropyl)-1,2-

H/α-CN and H/β-CN rate ratios have been measured for the solvolysis of sulfonate esters of relatively simple, noncyclic aliphatic alcohols.The β-CN function was found to be far more rate retarding than the α-CN function.

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Novel P-stereogenic pincer-Ni complexes {κP,κC,κP-3,5-Me2-2,6-(MetBuPCH2)2C6H}NiCl (3), {κP,κC,κP-3,5-Me2-2,6-(MetBuPCH2)2C6H}NiOTf (4), [{κP,κN,κP-2,6-(MetBuPCH2)2C5H3N}NiCl]Cl (7), [{κP,κN,κP-2,6-(MetBuPCH2)2C5H3N}NiCl]BF4 (8), and [{κP,κN,κP-2,6-(MetBuPCH2)2C5H3N}Ni(NCMe)](BF4)2 (9) were synthesized in 55-84% yields and characterized by 1H NMR, 13C{1H} NMR, 31P{1H} NMR, 19F{1H} NMR, and/or single-crystal X-ray diffractions. The ORTEP diagrams of complexes 3, 7, 8, and 9 show that the coordination geometries around the Ni center in all these structures are approximately square planar but have different bond lengths and angles. These complexes were shown to be active catalysts for the asymmetric aza-Michael addition of α,β-unsaturated nitriles. For most examples good to excellent yields (up to 99%) and moderate enantiomeric excesses (up to 46% ee) were obtained. Notably, the PCP complex 3 exhibited higher catalytic activity in the aza-Michael addition than the PNP complexes 7, 8, and 9. Two achiral PCP-type pincer-Ni complexes, {κP,κC,κP-3,5-Me2-2,6-(tBu2PCH2)2C6H}NiCl (11) and {κP,κC,κP-3,5-Me2-2,6-(Ph2PCH2)2C6H}NiCl (13), were also synthesized and fully characterized in order to reveal the structural differences between the chiral and achiral complexes. (Chemical Equation Presented).

Here we report that chiral Mn(I) complexes are capable of H-P bond activation. This activation mode enables a general method for the hydrophosphination of internal and terminal α,β-unsaturated nitriles. Metal-ligand cooperation, a strategy previously not considered for catalytic H-P bond activation, is at the base of the mechanistic action of the Mn(I)-based catalyst. Our computational studies support a stepwise mechanism for the hydrophosphination and provide insight into the origin of the enantioselectivity.

The effect of viscosity on the diffusion efficiency (Fdif) of an organic radical pair in a solvent cage and the termination mechanism, that is, the selectivity of disproportionation (Disp) and combination (Comb) of the geminated caged radical pair and the diffused radicals encountered, were investigated quantitatively by following the photolysis of dimethyl 2,2′-azobis(2-methylpropionate) (V-601) in the absence and presence of PhSD. Fdif and Disp/Comb selectivity outside the cage [Disp(dif)/Comb(dif)] are highly sensitive to the viscosity. In contrast, the Disp/Comb selectivity inside the cage [Disp(cage)/Comb(cage)] is rather insensitive. The difference in viscosity dependence between Disp(cage)/Comb(cage) and Disp(dif)/Comb(dif) is explained by the spin state of the radical pair inside and outside the cage and the spin state dependent configurational changes of the radical pair upon their collision. Given that the configurational change of the radicals associates the displacement and reorganization of solvents around the radicals, the termination outside the cage, which requires larger change than that inside the cage, is highly viscosity dependent. Furthermore, while the bulk viscosity of each solvent shows good correlation with Fdif and Disp/Comb selectivity, microviscosity is the better parameter predicting Fdif and Disp(dif)/Comb(dif) selectivity regardless of the solvents.

The invention relates to the field of fine chemical industry, and in particular relates to a method for preparing (methyl) acrylonitrile by dehydration of (methyl) acrylamide. The method for preparingthe (methyl) acrylonitrile by dehydration of secondary catalytic raw material (methyl) acrylamide comprises the following steps: firstly, carrying out dehydration reaction on the (methyl) acrylamidein a homogeneous system, and then carrying out secondary catalytic dehydration reaction in a reaction bed by using a mesoporous organometallic palladium catalyst. The method can reduce the generationof waste water and waste, and has relatively higher (methyl) acrylamide conversion rate and higher (methyl) acrylonitrile single-pass yield. The method has mild reaction conditions, rapid reaction, simple process and easy operation, and is suitable for industrial production.

A three-stage method for synthesizing 1,1-disubstituted olefins is provided.

Megawatt KrF laser gas-phase photolysis of benzene and acetonitrile-benzene mixture was studied by using mass spectroscopy-gas-chromatography and Fourier transform infrared spectroscopy for analyses of volatile products, and by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, electron microscopy and magnetization measurements for analyses of solid products deposited from the gas-phase. The results are consistent with carbonization of benzene and decomposition of non-absorbing acetonitrile in carbonizing benzene through collisions with excited benzene and/or its fragments. The solid products from benzene and acetonitrile-benzene mixture have large surface area and are characterized as nanomagnetic amorphous carbonaceous soot containing unsaturated C centers prone to oxidation. The nanosoot from acetonitrile-benzene mixture incorporates CN groups, confirms reactions of benzene fragments with CN radical and has a potential for modification by reactions at the CN bonds.

The thermal decomposition of different classes of RAFT/MADIX agents, namely dithioesters, trithiocarbonates, xanthates, and dithiocarbamates, were investigated through heating in solution. It was found that the decomposition behavior is complicated interplay of the effects of stabilizing Z-group and leaving R-group. The mechanism of the decomposition is mainly through three pathways, i.e., β-elimination, α-elimination, and homolysis of dithiocarbamate (particularly for universal RAFT agent). The most important pathway is the β-elimination of thiocarbonylthio compounds possessing β-hydrogen, leading to the formation unsaturated species. For the leaving group containing solely α-hydrogen, such as benzyl, α-elimination takes place, resulting in the formation of (E)-stilbene through a carbene intermediate. Homolysis occurs specifically in the case of a universal RAFT agent, in which a thiocarbonyl radical and an alkylthio radical are generated, finally forming thiolactone through a radical process. The stabilities of the RAFT/MADIX agents are investigated by measuring the apparent kinetics and activation energy of the thermal decomposition reactions. Both Z-group and R-group influence the stability of the agents through electronic and steric effects. Lone pair electron donating heteroatoms of Z-group show a remarkable stabilizing effect while electron withdrawing substituents, either in Z- or R-group, tends to destabilize the agent. In addition, bulkier or more β-hydrogens result in faster decomposition rate or lower decomposition temperature. Thus, the stability of the RAFT/MAIDX agents decreases in the order where R is (with identical Z = phenyl) -CH2Ph (5) > -PS (PS-RAFT 15) > -C(Me)HPh (2) > -C(Me)2C(=O)OC2H5 (7) > -C(Me)2Ph(1) > -PMMA (PMMA-RAFT 16) > -C(Me) 2CN (6). For those possessing identical leaving group such as 1-phenylethyl, the stability decreases in the order of O-ethyl (11) > -N(CH2CH3)2 (13) > -SCH(CH3)Ph (8) > -Ph (2) > -CH2Ph (4) > -PhNO2 (3). These results consort with the chain transfer acitivities measured by the CSIRO group and agree well with the ab initio theoretical results by Coote. In addition, the difference between thermal stabilities of the universal RAFT agents at neutral and protonated states has also been demonstrated.

Finding complex organic molecules in the interstellar medium (ISM) is a major concern for understanding the possible role of interstellar organic chemistry in the synthesis of prebiotic species. The present interdisciplinary report is a prospective study aimed at helping detection of heteroaromatic compounds or at least of some of their isomers in the ISM. The thermodynamic stabilities of the C4H5N, C4H4O, C4H4S families were calculated using density functional theory (DFT). It was found that pyrrole, furan and thiophene are unambiguously the most stable isomers at the 10-50 K temperatures of the ISM. Several of the less stable isomers were synthesized and flash vacuum thermolysis experiments were performed on these species. Although the detection of pyrrole in the pyrolysis of many compounds has been reported in the literature, we observed that none of its isomers led to pyrrole in these conditions, which suggests that other formation routes are to be considered. On the other hand, these three aromatic compounds present a very high stability, few % been decomposed at 1500 K by flash vacuum thermolysis; these experiments also show a great stability of crotonitrile that is the most stable compound that can be formed in these conditions. The rotational constants, dipole moments and IR frequencies of the low-lying isomers are given to encourage laboratory experiments on these prototype molecules.

An improved single-step catalytic (amm)oxidation process for the conversion of one or more C3 to C5 alkanes, in the presence of supercritical fluid, to one or more (amm)oxidation products, such as unsaturated carboxylic acids and unsaturated nitriles.

A number of triflates have been shown to undergo clean pseudo-first-order solvolysis reactions in DMSO-d6 to give products derived from carbocationic intermediates. Thus, t-BuCH(OTf)CO-t-Bu (5) and t-BuCH 2OTf (9) react readily in DMSO-d6 at 25 °C to give a rearranged oxosulfonium salts, and subsequent alkene products where methyl migration to the incipient cationic center occurs. t-BuCH(OTf)CO 2CH3 (14) gives analogous rearranged products, and 1-methylcyclopropyl triflate (21) gives a ring-opened allylic oxosulfonium salt. These triflates react primarily via kΔ pathways. 6-Methylbicyclo[3.1.0]hex-6-yl triflate (23), bicyclo[2.2.1hept-1-yl triflate (24), 1,6-methano[10]-annulen-11-yl triflate (25), (CH3) 2C(OTf)CO2CH3 (26), and (CH3) 2CCN(OTf) (29) all react in DMSO-d6 to give carbocation-derived products. PhCH(OTf)CF3 (33) and substituted analogues also react readily in DMSO-d6, and the Hammett ρ + value is -3.7. This suggests a "borderline" mechanism where the transition state has substantial charge development. The primary feature of these solvolyses is the high reactivity of all of these triflates in DMSO-d6. Thus, these triflates are all more reactive in DMSO-d 6 than in HOAc, and for most, rates are faster than in CF 3CH2OH. Triflates 5, 21, 29, and 33 are 10 8-109 times more reactive in DMSO-d6 than the corresponding mesylates. It is suggested that the decreased need for electrophilic solvation of trifiate anion, and the high cation solvating ability of DMSO, are the reasons for the high triflate reactivity in DMSO-d 6.

The present invention provides an improvement in a process and apparatus for manufacturing acrylonitrile by the vapor phase ammoxidation of a hydrocarbon. The invention comprises contacting the gaseous product stream with a quench fluid in a reverse jet scrubber. The quenching fluid is injected counter-current to the gas flow, and the gas velocity is sufficient to reverse the flow direction of the water, thereby forming a standing wave or froth zone wherein the quench is rapidly achieved. The quench fluid may be obtained from many sources, but is preferably obtained from a waste process stream emanating from a subsequent recovery or purification step. The quench fluid may contain acid to facilitate removal of ammonia from the gas stream. The quench fluid that is not vaporized may be recirculated. Impurities and contaminants may be removed from the quench fluid prior to recycle. In a most preferred embodiment, the quench fluid is not cooled during recirculation, and the cooling process is essentially adiabatic, with the sensible heat of the hot gaseous stream being converted to latent heat in the form of vapor.

The invention relates to a process for the preparation of α-chloronitriles by reaction of cyanohydrins of aldehydes or ketones with phosgene using a phosphine oxide as catalyst.

The catalytic properties of a Fe-Te-Mo oxide catalyst promoted by beryllium ions were studied in simultaneous reactions of oxidative ammonolysis of isobutylene and oxidative dehydrogenation of butene-1.

The catalytic properties of a new family of crystalline Re-Sb-O compounds SbRe2O6, SbOReO4·2H2O, and Sb4Re2O13 in selective ammoxidation of isobutylene to methacrylonitrile (MAN) have been studied and compared with those of a coprecipitated SbRe2Ox catalyst, an Sb2O3-supported Re2O7 catalyst, bulk Re oxides, and bulk Sb oxides. The Re-based catalysts were more or less active for MAN synthesis with selectivities of 47.9-83.6% at 673 K, whereas bulk Sb oxides (Sb2O3 and Sb2O4) showed no activity. The results demonstrate that Re is prerequisite for the ammoxidation catalysis of Re-Sb-O systems. In catalytic systems the presence of Sb also contributes to the ammoxidation catalysis for MAN synthesis. Among these catalysts, SbRe2O6 was most active and selective (83.6%) for MAN formation at 673 K. No structural change in the bulk and surface of SbRe2O6 was observed after i-C4H8 ammoxidation by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and confocal laser Raman microspectroscopy. The good performance of SbRe2O6 may be ascribed to its specific crystal structure composed of alternate octahedral (Re2O6)3- and (SbO)+ layers. Pulse reaction results suggested that adsorbed NH3 species on the SbRe2O6 catalyst facilitated the adsorption and subsequent activation of isobutylene. Increasing reaction temperature and decreasing GHSV did not give rise to increasing formation of by-products CO2 and acetonitrile, while increasing the i-C4H8 conversion. Thus the crystalline SbRe2O6 compound may be a new promising catalyst for ammoxidation of light hydrocarbons.

The catalytic ammoxidation of isobutane to methacrylonitrile at 673 K proceeds on a new class of Re mixed-oxide SbRe2O6 with alternate (Re2O6)3- and (SbO)+ layers, where ammonia is prerequisite for the C-H bond scission of isobutane.

Disclosed is an ammoxidation catalyst composition for use in producing acrylonitrile from propylene, or methacrylonitrile from isobutylene, by ammoxidation of the propylene or of the isobutylene, comprising an oxide catalyst and a silica carrier having the oxide catalyst supported thereon, wherein the silica carrier is present in an amount of from 40 to 60% by weight, based on the total weight of the oxide catalyst and the silica carrier. The oxide catalyst comprises oxides of molybdenum, bismuth, iron, and component A which is at least one element selected from potassium, rubidium and cesium, wherein bismuth, iron and component A are, respectively, present in amounts of from 0.1 to 6, from 0.1 to 8 and from 0.01 to 0.5 in terms of atomic ratios relative to twelve atoms of molybdenum. The ammoxidation catalyst composition is prepared by providing a slurry comprised of a silica sol and sources of component metallic elements of the oxide catalyst, and spray-drying the slurry, followed by calcination, wherein the silica sol has an aluminum content of 0.04 or less in terms of an atomic ratio relative to 100 atoms of silicon. By use of the catalyst composition of the present invention, the selectivity for acrylonitrile or methacrylonitrile can be significantly improved.

The Pt-Sn/SiO2 catalysts prepared by selective bimetallic CVD reaction of SnMe4 with Pt particles on SiO2, characterized by EXAFS (extended X-ray absorption fine structure), yield acrylonitrile from NO + propene and methacrylonitrile from NO + isobutene and NO + isobutane with good selectivities, typically 70-93percent, in contrast to negligible activity and selectivity (about one order of magnitude lower) with the monometallic Pt/SiO2 catalyst.

A process for producing a nitrile, which comprises subjecting an alkane and ammonia in the gaseous state to catalytic oxidation in the presence of a catalyst which satisfies the following conditions of (1) and (2): (1) the catalyst is represented by the empirical formula: wherein X is at least one element selected from the group consisting of Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B and Ce, ______________________________________ when a = 1, b = 0.01 to 1.0, c = 0.01 to 1.0, x = 0.01 to 1.0,______________________________________ and n is a number such that the total valency of the metal elements is satisfied; and (2) the catalyst has X-ray diffraction peaks at the following angles of 2θ in its X-ray diffraction pattern:______________________________________Diffraction angles of 2θ (°)______________________________________ 22.1 ± 0.3 28.2 ± 0.3 36.2 ± 0.3 45.2 ± 0.3 50.0 ± 0.3.______________________________________

1,1-disubstituted ethylene compounds of the general formula I STR1 where Z is COOR2, CN or COR3, R1 is an aliphatic, cycloalophatic, araliphatic, aromatic or heterocyclic radical which may be further substituted by functional groups which are inert under the reaction conditions, R2 is an aliphatic, cycloaliphatic or araliphatic radical of 1 to 15 carbon atoms and R3 is an aliphatic, cycloaliphatic or araliphatic radical of 1 to 15 carbon atoms which may be substituted by groups which are inert under the reaction conditions, and R1 together with R2 or R1 together with R3 may furthermore form an alkylene chain of 2 to 10 carbon atoms which may be substituted by groups which are inert under the reaction conditions, are prepared from a formyl compound of the general formula II STR2 where Z, R1, R2 and R3 have the above meanings, by a process in which the reaction is carried out in the presence of formaldehyde or paraformaldehyde and (a) a C1 -C12 -alkanol or (b) a mixture of a C1 -C12 -alkanol and water or (c) with water in the presence of a secondary amine and a protic acid at from 0° to 200° C.

Iron-antimony metallic oxide catalysts which have become deactivated after being used for the production of aldehydes, acids, nitriles, or dienes through oxidation, ammoxidation, or oxidative dehydrogenation of organic compounds in fluidized-bed reactors are regenerated by adding to the catalyst a molybdenum-enriched catalyst formed by supporting a molybdenum component which is volatile or capable of forming a volatile compound under reaction conditions on a metallic oxide catalyst. The metallic oxide catalysts contain as essential components (I) Fe, (II) Sb, (III) at least one element selected from the group consisting of V, Mo and W, and (IV) Te.

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The carbon-skeleton rearrangements as catalyzed by heptamethyl cobyrinate perchlorate, 1ester>ClO4, were investigated under electrochemical conditions.The controlled-potential electrolysis of 2,2-bis(ethoxycarbonyl)-1-bromopropane, which is considered to be a model substrate for methylmalonyl-CoA mutase, was catalyzed by 1ester>ClO4 in N,N-dimethylformamide to give the rearrangement product, 1,2-bis(ethoxycarbonyl)propane, as a major one at -1.5 V vs.SCE in the presence of acetic acid and at potentials more cathodic than -1.8 V vs.SCE without acetic acid in the dark.The electrochemical carbon-skeleton rearrangement was postulated to proceed via formation of anionic intermediates.The electrolyses of 1-bromo-2-cyano-2-ethoxycarbonylpropane, 2-acetyl-1-bromo-2-ethoxycarbonylpropane, and 1-bromo-2-propane with 1ester>ClO4 also afforded the corresponding carbon-skeleton rearrangement products.The results indicated that substrates with two electron-withdrawing groups placed on the β-carbon atom with combination of one carboxylic ester and one of carboxylic ester, acetyl, and cyano moieties readily gave the corresponding rearrangement products which were derived from individual migration of the substituent groups.Substrates with only one of the electron-withdrawing groups, carboxylic ester, acetyl, and cyano, did not give any rearrangement product, but a substrate with one thioester group afforded the corresponding rearrangement product.The migratory aptitude of electron-withdrawing groups was found to decrease in the order: COSR>COR>COOR>CN.Both electronic character and steric bulkiness of the migrating groups are apparently reflected on this tendency, even though relative contributions of these effects are much dependent on the nature of β-substituents.

The ammonoxidation of propene and isobutene were studied over mixed SnO2-Sb2O4 catalysts in a pulse reactor in the range of 573-698 K.From the aspect of acrylonitrile and methacrylonitrile production, the catalysts of compositions Sn:Sb=1-5:1 behaved most appropriately at the optimum reaction temperature of 673 K.The formation of (meth)acrylonitrile can be interpreted in terms of a possible mechanism including the adsorption of olefins on surface Sn4+ centers and the formation of ?-allyl complexes.Selective oxidation products are formed only in the presence of Sb, from which it may be concluded that (NH)2- ions produced in the oxidation of NH3 can be incorporated into the ?-allyl complex only through the participation of centers involving Sn ions via carbene and imide intermediates.Sn2+ ions may be due to reoxidation of the catalyst.

The kinetics of the decomposition of azobisiobutyronitrile in the 1,2-dichloroethane-carbon tetrachloride-chlorine system have been investigated and it is shown that, in free-radical chlorination, there is competition between the chain and unimolecular mechanisms of the decomposition of azobisiobutyronitrile.

The addition of the complexes of amines with sulfur dioxide to acrylonitrile, methacrylonitrile, and crotononitrile was relized.The reactions of acrylonitrile with CH3NH2 -> SO2 and C2H5NH2 -> SO2 complexes take place with the formation of N-alkyl-2-cyanoethanesulfonamides (S-addition of the complexes at the double bond).The electrophilic alkenes react with (CH3)2NH -> SO2 and (C2H5)2NH -> SO2 to form complexes of the substituted β-aminonitriles with sulfur dioxide (N-addition of the complexes at the double bond).

Azobisisobutyronitrile (ABIBN) is used as an initiator of radial reactions, including chlorination of chloroaliphatic and alkylaromatic compounds. A mechanism of ABIBN decomposition in the presence of chlorine is proposed which studied chlorination of ABIBN in carbon tetrachloride by molecular chlorine. It was found with the aid of gas chromatography - mass spectrometry that the reaction mass contained 12 products of ABIBN decomposition. They can be subdivided into four groups in accordance with their structure and possible routes of formation.

The generation of cyanopropyl radical pairs by the photolysis of azobis(isobutyronitrile) (AIBN) adsorbed on dry silica gel-benzene slurries has been investigated.The results require revision of an earlier observation that restrictions on the rotational motion of cyanopropyl radicals at a silica gel-benzene interface prevented the formation of the unsymmetrical coupling product dimethyl-N-(2-cyano-2-propyl)ketenimine.Both tetramethylsuccinodinitrile and the ketenimine were formed on the silica gel surface, even when dry, although the latter was partially hydrolyzed to the corresponding amide.Measurements of geminate recombination of radicals produced by direct photolysis of mixtures of deuterated and nondeuterated AIBN indicated that some radicals could escape, by translational motion, from their original geminate partners.The amount of translational motion was increased for the same cyanopropyl radical pair generated by triplet-sensitized AIBN decomposition.This latter observation supports the view that the triplet-sensitized decomposition of AIBN occurs directly from an exited state rather than by isomerization to a thermally labile cis isomer.

During the investigation of the ammoxidation of a technical butadiene-free pyrolytic C4-fraction on active catalysts of the type of multicomponent molybdates in the temperature range of 573-633 K in a fluidized bed reactor the following fact was observed: whereas at the beginning of the process isobutene and n-butene are converted into methacrylonitrile and butadiene, respectively, later in the C4-olefins are oxidized to carbon monoxide with high selectivity.It is suggested that this phenomenon is caused by reduction damage of the catalyst due to the hindered desorption of the reaction products.

A process for regenerating an antimony containing metal oxide catalyst which comprises impregnating aqueous ammonia in an amount corresponding to the pore volume of the catalyst, to a metal oxide catalyst whose activity has been deteriorated, the catalyst containing an essential components (A) antimony, (B) at least one element selected from the group consisting of iron, cobalt, nickel, manganese, uranium, cerium, tin and copper, (C) at least one element selected from the group consisting of vanadium, molybdenum and tungsten and (D) tellurium, drying the catalyst, and calcining the catalyst in a non-reducing atmosphere at a temperature in the range of about 550° C. to about 950° C.

Dibromides are readily debrominated by means of poly(styrylmethyl thiolate) with formation of the respective olefins.The polymeric reagent with a high content of sulphhydryl groups can be easily prepared from chloromethylated polystyrene; it extends possibilities of protection-deprotection reactions of the double bond.

The present invention relates to a process of the conversion of tert-butyl alkanoates to methacrolein or methacrylonitrile, and more particularly to a process for the conversion of tert-butyl acetate to methacrolein or methacrylonitrile.

Various proportion of nickel oxide were deposited on aerogel supports of alumina, silica or magnesia or on binary aerogel supports of silica-alumina or alumina-magnesia.The catalytic activity and selectivity of these solids in the conversion of isobutene by nitric oxide into methacrylonitrile at 410 deg C leads to the recognition of four types of influence of the nature of the support.The support by reacting in the solid state with nickel oxide, can form a new phase which favours the selectivity into nitrile (system NiO-Al2O3).In the absence of an interaction with the active component (NiO) the carrier simply contributes to its better dispersion (system NiO-SiO2).It can also exhibit a catalytic activity which, in the present case favours a total oxidation (system NiO-MgO).Finally, a binary support (system NiO-Al2O3-SiO2) increases acid properties of the catalyst which are the cause of a modification of the selectivity spectrum of the contact.

The reaction of isobutane with nitric oxide leads to the formation of methacrylonitrile and also acrylonitrile and acetonitrile in the presence of binary aerogel catalysts NiO-Al2O3 or NiO-Fe2O3 and ternary NiO-Fe2O3-Al2O3.The best results as far as the catalytic activity and selcectivity are concerned are obtained around 480 deg C on the ternary catalyst provided its iron content does not exceed 5 at.Fepercent.It is shown that the spinel phase NiAl2O4 favours the nitroxidation of the alkane into nitriles whereas the phase NiFe2O4 catalyses the oxidative degradation of the alcane.This last phase is detected when the iron content exceeds 5percent.If it is not the case, the presence of iron oxide not combined with NiO, this last component being sequestered by Al2O3 under the form of prespinel NiAl2O4, first favours a dehydrogenation of the alkane into alkene which is finally nitroxidated into nitriles.

Passage of unsaturated organic molecules trough a 13.56-MHz radio-frequency discharge, in the presence of cyanogen, results in the formation of unsaturated nitriles.Acrylonitrile was the major product from ethylene, propylene, acrolein, methyl vinyl ketone, or 1,1,1-trifluoropropylene. 1-Butene, 2-butene, and isobutylene gave mixtures of nitrile products with the CN situated at vinylic or allylic positions. 2-Butyne gave 1-cyanopropyne.Other compounds gave only low yields of nitriles and considerable polymer.The effects of power, pressure, flow rate, and ratios of reactants on the yields of acrylonitrile from propylene and cyanogen were studied.A typical power yield of acrylonitrile was 30 g kW-1 h-1.Maximum material yields of nitrile products were obtained at intermediate powers and pressures.The products are consistent with a reaction scheme involving attack of initially formed cyano radicals on the organic substrate.This step forms activated radical intermediates, which decay through elimination of an atom or group.The atom or group which is most weakly bound is preferentially lost.

The synthesis of methacrylonitrile by reaction of isobutane with nitric oxide at 480 degC over a ternary aerogel catalyst NiO-Fe2O3-Al2O3 obeys closely the "redox" model proposed by Mars and Van Krevelen: the catalyst is first reduced by hydrocarbon with formation of dehydrogenated radicals.The reduced catalyst is then reoxidized by nitric oxide which is decomposed into atomic nitrogen.A steady-state takes place between these two steps and the free radicals combine with atomic nitrogen to give methacrylonitrile.The formation of acrylonitrile and acetonitrile is due to the degradation of methacrylonitrile over a still fresh catalyst.

The catalytic transformation of isobutene by NO into methacrylonitrile was studied at 410 deg C with pure nickel oxide and nickel-oxide supported by alumina, silica, magnesia, alumina-magnesia, silica-alumina and silica-magnesia under the form of mixed aerogels (binary or ternary).The selectivity towards methacrylonitrile is of the order of 70-80 percent for all the catalysts excepted for those containing large amounts of magnesia (selectivity of the order of 50 percent).The acidity of the catalysts, which is supplied by the supports, exerts as influence on the carbon deposit rate necessary to reach a steady state of activity.It seems also to be at the origin of a selectivity towards partial oxidation reactions during the transient step of the catalysis.The best selective and stable catalyst is the binary NiO-Al2O3 aerogel catalyst.Its catalytic properties seem to be linked with the presence of a prespinel phase NiAl2O4 which is detected by XRD at the end of the activation treatment at 410 deg C.

Binary mixed aerogel oxides of chromium and aluminium or containing in addition magnesia, are good catalysts for the nitroxidation of propene and isobutene by NO.Their selectivities towards acrylo-and methacrylo-nitriles formation are of the same order as those exhibited under the same conditions, by the binary aerogels NiO-Al2O3.Addition of magnesia to the Cr2O3-Al2O3 system increases its stability with time on stream.Kinetic data for the nitroxidation of isobutene are in agreement with the > model already proposed in the case of the catalysts NiO-Al2O3.

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Treatment of allylamido-phosphonium salts with dry tetrabutylammonium cyanide in methylenechloride delivers after removal of the allyl group phosphinous acid amides with retention of configuration (P-C-cyanolysis).Allyl-O-alkylphosphonium salts undergo the Arbosov reaction under the above conditions, while allyl-S-alkyl phosphonium salts undergo fission of the P-S bond (P-S cyanolysis).Equally good results were obtained using KCN in methylene chloride accompained by catalytic amounts of 18-crown-6 ether; thus optically active benzyl-methyl-phenyl-phosphine-sulfid gave the corresponding phosphine with retention of configuration.Dithiophosphinic acid esters and thiophosphinic acid amides, after conversion to the corresponding quasiphosphonium salts via S-alkylation and subsequent treatment with tetrabutylammonium cyanide in methylenechloride, also give the corresponding thiophosphinous acid ester and phosphinous acid amide respectively.Thiophosphinic acid O-alkyl esters (R2P(S)OR') give however the thiophosphinic S-alkyl ester (R2P(O)SR') via an Arbusov reaction.The P-C cyanolysis of allyl-triphenylphosphoniumbromide using KCN/18-crown-6 or tetrabutylammonium cyanide in aprotic medium stops at the stage of the intermediary red-coloured ylide; addition of a proton-donor then results in the subsequent rearrangement to the corresponding propenyl-phosphonium salt.

Three 2-substituted-2-propyl acetates undergo a homogeneous, first-order, unimolecular elimination in the gas phase at temperatures from 230 to 340 deg C and pressures from 56 to 210 mmHg.The rate constants are expressible by the Arrhenius equation: for 2,3,3-trimethyl-2-butyl acetate, log k (s-1) = (14.40 +/- 0.49) - (171.5 +/- 4.6) kJ mol-1 (2.303RT)-1; for α-acetoxyisobutyronitrile, log k (s-1) = (14.45 +/- 0.82) - (198.7 +/- 8.8) kJ mol-1 (2.303RT)-1; for methyl α-acetoxyisobutyrate, log k (s-1) = (12.53 +/- 0.32) - (176.1 +/- 3.6) kJ mol-1 (2.303RT)-1.The Taft correlation for the pyrolyses of tertiary esters with substituents on the α-carbon is projected and discussed.Many of these substituents enhance the elimination by steric accelaration.

In the method of making a compound of the formula STR1 wherein X is carboxyl, a carboxylic acid ester group --COOR2, or cyano, by reaction of a compound of the formula CH3 CH2 X with methylal in the presence of a catalyst, the improvement wherein said catalyst is a catalyst system which consists essentially of (1) silicon dioxide dosed with a basic component and (2) a member selected from the group consisting of aluminum oxide and titanium dioxide.