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Platinum catalysts supported on gamma-alumina and on a variety of zeolites have been characterized and evaluated for activity in the transfer hydrogenation of propylene using butanes as the hydrogen source. Zeolite supports evaluated include both aluminosilicates and borosilicates having the ZSM-5 and beta structures. Platinum on acid zeolites shows enhanced activity for the hydrogen transfer, compared to platinum supported on alumina. However, with platinum on acidic zeolites, propylene hydrogenation is accompanied by a number of competing, acid-catalyzed reactions which lower the selectivity to propane and butenes. Of the acid zeolites studied, low aluminum, borosilicates were found to be more selective than the corresponding aluminosilicates of similar structure. Partial neutralization of the zeolitic acidity with alkali cations lowered the nonselective acid catalysis. Metal-catalyzed hydrogen transfer activity was not diminished by this partial neutralization so that hydrogen transfer selectivity increased. In the case of the borosilicate-supported catalysts, maximum activity near 90% conversion of propylene to propane and selectivity for hydrogen transfer greater than 95% were obtained when sufficient alkali was added to neutralize the acidity associated with framework aluminum while maintaining the acidity associated with boron. Feed studies with an optimized catalyst provide additional mechanistic insights.

n -Butene was isomerized to isobutene over fresh and used ferrierite catalysts. Activity and selectivity for skeletal isomerization and biproduct formation were measured and changes following extended use were related to changes in ferrierite′s aluminum distribution. In its fresh form, ferrierite exhibited high activity for n -butene conversion and high selectivity for non-C 4 products with reduced selectivity for isobutene. With time on feed, side-product formation decreased and isobutene yields reached a maximum, then declined with further time on feed. After several run/regeneration cycles, a marked drop-off in the maximum achievable isobutene yield was observed and selectivity for non-C 4 products increased. MAS-NMR of the deactivated catalyst showed a decrease in zeolitic, tetrahedral aluminum and an increase in octahedral aluminum. In order to understand changes occurring following extended use, ferrierite powders were modified by steam and by steam plus acid-wash treatments. A steamed ferrierite catalyst exhibited lower initial n -butene conversion; however, selectivity to non-C 4 , products increased relative to that of the fresh catalyst. XRD peak areas and gravimetric adsorption data indicated excellent crystallinity retention following steam treatment; XRD unit cell determination, and FTIR and NMR analysis suggested significant framework dealumination and the creation of a nonframework aluminum phase. TEM suggested that at least a portion of this phase exists in mesopores created by steam treatment. A steamed-acid-washed ferrierite catalyst also exhibited reduced initial n -butene conversion but high isobutene selectivity throughout the run. Biproduct formation was greatly reduced. Characterization indicated that acid-wash treatment after steaming had no effect on framework aluminum but partially reduced the amount of nonframework aluminum. Steamed-acid-washed ferrierite was much less sensitive to subsequent hydrothermal treatments than was the starting ferrierite. The study suggests a catalytic role for nonframework alumina, generated upon extended use of unmodified ferrierite and present in steamed ferrierite. Catalytically active, nonframework sites contribute to the production of non-C 4 products and reduced isobutene selectivity. Steamed-acid-washed ferrierite with the active nonframework phase removed exhibits excellent isobutene selectivity and catalytic stability.

To a large extent, the depletion of tolyltriazole (TTZ) observed in several field tests may be attributed to the formation of a protective copper-triazole layer. Laboratory aging studies, shown to correlate with field experience, reveal that copper-TTZ layer formation depletes coolant TTZ levels in a fashion analogous to changes observed in the field. XPS and TPD-MS characterization of the complex formed indicates a strong chemical bond between copper and the adsorbed TTZ which can be desorbed thermally only at elevated temperatures. Electrochemical polarization experiments indicate that the layer provides good copper protection even when TTZ is absent from the coolant phase. Examination of copper cooling system components obtained after extensive field use reveals the presence of a similar protective layer.

Effects of zeolite pore structure on skeletal isomerization of 1-butenes are investigated. Three 10-member ring zeolites, ferrierite, ZSM-23, and ZSM-5, are studied and compared. Results show that ferrierite, with intersecting 10-MR and 8-MR channels, has better isomerization activity than ZSM-23, with monodirectional 10-MR channels, ZSM-5 with two intersecting 10-MR channels is not a selective isomerization catalyst.

This paper reports on the selective hydroperoxidation of unsaturated elastomers by using singlet oxygen photochemically produced (sensitization by anthracene at 365 nm). Hydroperoxide groups were characterized by using derivatization by nitric oxide and dimethyl sulfide. Grafting was performed by decomposing of hydroperoxide groups in the presence of acrylate monomers or nitroxyl radicals. According to the substituents, in acrylate hindered amine stabilizers (HAS) can be obtained. In the last part, the effect of grafted HAS on photo and thermal ageing of the parent elastomer is reported.

Wet chemistry test methods have been developed to determine the level of alkyl carboxylate inhibition remaining in used OAT coolants. The test strategy of these methods depends on the known alkyl carboxylate ability to protect cooling system metals such as aluminum by forming insoluble metal soaps. Various test configurations make this test strategy suitable for the rapid analysis of used coolants in the field. This paper will document the initial test strategies and the development efforts that led to the first field test for alkyl carboxylate-based coolants. Test kit performance with laboratory and field samples is also discussed.

The conversion of normal olefins such as n-butylenes can be converted to branched olefin species such as isobutylene by skeletal isomerization over zeolite-based catalysts having pore sizes of at least about 4.5 Angstroms and a pore structure characterized by intersecting 10-MR and 8 MR channels. The zeolite-based catalysts have sufficient acidity to catalyze the skeletal isomerization of normal olefins. The catalysts can be used to produce isoolefins for reaction with alcohols in integrated processes to produce alkyl tertiary alkyl ethers such as MTBE.

The effects of midbrain raphe stimulation and/or harmaline administration on cerebellar cell activities were examined in chloralosed rats. Cerebellar cortical cells were grouped into two categories. From a total sample of 68 cells, 48 were classified as Purkinje cells and the 20 others were unidentified. Midbrain raphe stimulation was found to inhibit for many sec the discharge of 40% of the Purkinje cells and 80% of the unidentified units. Other cells were unaffected, except 4 of them which were excited. Harmaline administration increased the CS firing rate of all Purkinje cells by inducing a rhythmic CS discharge at 7-12 Hz. Moreover, harmaline increased the discharge rate of unidentified units without inducing rhythmic activity. In both types of cerebellar cells a modulation of their firing pattern by periodical pauses at 0.1-0.4/s was noticed. These data are discussed in relation to the known influences of harmaline and cerebellar stimulation on raphe neurons. Taken in this context, results presented here confirm the existence of a modulatory influence of the raphe nuclei on the olivo-cerebellar circuitry. A general model of interactions is proposed.

The firing patterns of single raphe units at the posterior midbrain level were examined in chloralosed rats to assess the effects of cerebellar stimulation and/or harmaline administration. Raphe cells were grouped according to their spontaneous firing rate and other characteristics into two categories. From a total sample of 160 cells, 106 (66%) presenting a slow regular discharge pattern were classified as serotonergic (5-HT cells), whereas 35 (22%), having a faster firing rate, were considered non serotonergic (NS cells). Moreover, 19 (12%) raphe units were non categorized. Cerebellar juxtafastigial (JF) stimulation modified the discharge pattern of 56 (35%) raphe units. The remaining 65% were unaffected by the stimulation. Of the 41 5-HT cells affected by JF stimulation, 28 neurons (68%) showed a systematic increase of their firing rate, whereas of the 12 NS cells affected 8 neurons (66%) were inhibited. It thus appears that cerebellar stimulation has an opposite effect on raphe units according to the cell types. Harmaline administration suppressed the activity of 5-HT cells and increased the discharge rate of NS cells. Moreover, we noticed in the latter units a phase modulation of the firing pattern by pauses occurring with a fixed periodicity of 2.5 to 10 s. Considered in the context of previous studies, these results strongly suggest an inhibitory influence of the raphe system on the olivo-cerebellar circuitry.

Responses of cerebellar Purkinje cells to mechanical stimulation of the Achilles' tendon were studied in unanesthetized decerebrate cats. Approximately two-thirds of the Purkinje cells tested were activated in response to stimulation through climbing fibers, i.e., they generated a complex spike. In half of these cells (group A) the probability of appearance of a complex spike to a blow on the tendon was from 0.5 to 0.9 and the latent period of response from 20 to 25 msec. Purkinje cells with a latent period of response of over 35 msec were characterized by low probability of response (under 0.5) to a tap (group B). Responses of Purkinje cells to excitation of mossy fibers were weaker and more varied.

The reduction of the dioxygen species [{RhCl(O2)(PPh3)2}2] with ethanol in the presence of 1 equivalent of a phosphine ligand, L, other than PPh3, gives a catalytically active mixture having a PPh3 : L ratio of 3 : 1. When the reduction is carried out under hydrogen, this mixture is composed of two species, [RhClH2(PPh3)2] and [RhClH2(PPh3)L]. A comparison is made of the rate and stereochemical data obtained using these mixtures for the hydrogenation of 1-methylene-4-t-butylcyclohexane with data obtained using the [RhClL2] complexes as catalysts. This comparison and others have shown that in the mixed-ligand species, [RhClH2(PPh3)L], the ligand L is present exclusively at the site trans to the position of olefin complexation prior to hydrogen transfer.

The thermal and catalytic baseline runs continued with HDS-1442A as the reference catalyst and toluene soluble conversion as the basis for liquefaction performance. Results from these experiments suggested that a 30-minute run time should be selected for screening experiments. No promising candidates for testing in the continuous aging unit were identified. Catalyst Aging Tests: Eastern Coal was centered around evaluation of the new SRC II slurry oil as a liquefaction solvent as well as a design change in the catalyst basket for the continuous aging unit. Uncertainties in Run 5188 clouded the assessment of the slurry oil effect. Subsequent runs with the new SRC II solvent indicated that slurry oil effects are small. Catalyst Aging Tests: Western Coal concentrated on ascertaining the liquefaction behavior of a Western Coal such as Wyodak with AMOCAT type catalysts. Simplifications were made in the composition of our synthetic coal feed to improve analytical and kinetic accuracy. Using SRC II heavy distillate as the slurry oil and Illinois No. 6 coal feed, the results from the aging test are quite clear. The recently prepared 500 pound batch of AMOCAT 1A is good quality and exhibits highly improved performance over the H-Coal catalyst, HDS-1442A. Benzene andmore » hexane soluble conversion are markedly higher with hexane soluble conversion declining less rapidly with time. The highly improved catalyst should be considered for future evaluation in the larger H-Coal process development unit.« less

Work in Catalyst Preparation and Screening was concerned with modification of product workup procedure and elimination or reduction of uncertainties in the analysis of data from batch autoclave screening runs. Toluene was substituted for benzene as a solvent in the product workup because of the health hazard associated with the use of benzene and was added to the product prior to filtration in order to expose both liquid and solid product to the solvent. The conversion was about the same, using either the old benzene or new toluene product workup. The Engelhard dry coal charging device was used in an attempt to eliminate uncertainties in the batch screening data analysis. After considerable experimentation, use of the charging device was abandoned because of problems with plugging, temperature upsets, and catalyst coking. The effort in Catalyst Aging Tests with Eastern and Western Coal was centered around preparation of enough liquefaction solvent for the DOE program. In the application of new catalysts to the H-Coal process work centered around the 500 pound batch Amocat-1A (CoMo) received from W.R. Grace Company Catalyst inspection data were acceptable and, according to a recent HRI report, the performance results of the 500 pound batch were equivalent tomore » or better than those of an earlier experiment Amocat-1A that HRI tested. The batch of catalyst was also tested in our continuous flow pilot plant, but results were inconclusive since lined-out slurry oil contained unconverted coal particles.« less