Acenaphthylene, carbonization

Figures 53 (left) and 5.4 (right). Oxidation by molecular oxygen of PFA carbon, HIT 1073 K and of acenaphthylene carbons. Variation of CO/CO2 partial pressure ratios with reaction time (ks), with bum-off (wt%) (porosity) and with heat treatment temperature (K) (Marsh et al., 1981).

Thermolysis of trithiane (69) or carbonate (70) at reduced pressure yields methylene-thiirane which is stable in cold, dilute solution (Scheme 152) (78JA7436, 78RTC214). A novel acenaphthylene episulfide is obtained by treatment of the six-membered sulfoxide (71) with acetic anhydride (Scheme 153) (68JA1676), and photolysis of (72) gives a low yield of episulfide (73 Scheme 154) (72JA521). Low yields may be due to the desulfurization of the thiiranes under the reaction conditions. 

The oxidation of Me2S2 in the presence of aromatics with an increased electron density at several carbons, such as acenaphthylene or phenanthrene, and pyridine leads to similar products of vicinal functionalization (Scheme 32) [128]. 

Behymer and Hites (1985) determined the effect of different substrates on the rate of photooxidation of acenaphthylene using a rotary photoreactor equipped with a 450-W medium pressure mercury lamp X = 300-410 nm). The photolytic half-lives of acenaphthylene absorbed onto silica gel, alumina, fly ash, and carbon black were 0.7, 2.2, 44, and 170 h, respectively. 

Carbon blacks have been reported to be capable of initiating the cationic polymerization of vinyl monomers such as vinyl ethers, indene, and acenaphthylene. The grafting sites of the polymer were based on carboxyl groups present on the surface [88]. The polymerization was inhibited by treatment of the carbon blacks with NaHCOs, CH2N2, pyridine, and DMF. Also, the degree of conversion was found to be dependent on temperature and time of polymerization [89]. 

Thermolysis of indenone oxides (151) is an equally useful route to the betaines (150). Dimethyl acetylenedicarboxylate and compound 151 (R = R = Ph) at 175°C give adduct 153, and cyclohexanone at 150 C gives adduct 154. - Similarly, 1,3-dipolar adducts (e.g., 155) have been obtained using a wide variety of olefins—including cis- and [rans-, 2-dichloroethylene, dimethyl maleate, dimethyl fumarate, maleic anhydride, cis- and tran -stilbene, fran -dibenzoylethylene, tra .y-l,2-dicyanoethylene, A -phenylmaleimide, vinylene carbonate, acenaphthylene, and norbor-nadiene. With cis olefins the endo adduct (155) is usually the predominant isomer. Diphenylcyclopropenone gives compound 156 by spontaneous elimination of carbon monoxide from the initial adduct (157). Adduct 156... 

Two analytical methods for priority pollutants specified by the USEPA (38) use HPLC separation and fluorescence or electrochemical detection. Method 605, 40 CFR Part 136, determines benzidine and 3,3-dichlorobenzidine by amperometric detection at +0.80 V, versus a silver/silver chloride reference electrode, at a glassy carbon electrode. Separation is achieved with a 1 1 (v/v) mixture of acetonitrile and a pH 4.7 acetate buffer (1 M) under isocratic conditions on an ethyl-bonded reversed-phase column. Lower limits of detection are reported to be 0.05 /xg/L for benzidine and 0.1 /xg/L for 3,3-dichlorobenzidine. Method 610, 40 CFR Part 136, determines 16 PAHs by either GC or HPLC. The HPLC method is required when all 16 PAHs need to be individually determined. The GC method, which uses a packed column, cannot adequately individually resolve all 16 PAHs. The method specifies gradient elution of the PAHs from a reversed-phase analytical column and fluorescence detection with an excitation wavelength of 280 nm and an emission wavelength of 389 nm for all but three PAHs naphthalene, acenaphthylene, and acenaphthene. As a result of weak fluorescence, these three PAHs are detected with greater sensitivity by UV-absorption detection at 254 nm. Thus, the method requires that fluores-... 

An aromatic compound is an organic compound containing a ring of carbon atoms, usually unsaturated. such as a benzene, naphthalene, anthracene, and acenaphthylene ring. 

This reaction was first observed by Plate, Erivanskaya, and Khalima-Mansur over platinum-on-carbon and platinum-on-alumina catalysts (43-48). Platinum-on-carbon catalyzes this reaction between 310°C and 390°C (above which the catalyst is poisoned) (44). Over an acidic platinum-alumina catalyst containing 0.5 wt% platinum and 0.1 wt% sodium, 16.7% acenaphthenes and 1.5% acenaphthylene are obtained at 460°C and at 0.4 liquid hourly space velocity in hydrogen diluent. Conversions are considerably lower in helium. 

Propylnaphthalene can give two types of products by C5-dehydrocycli-zation dehydrocyclization at the pen-carbon atom of naphthalene gives 1-methylacenaphthene and 1 -methyl-acenaphthylene, while dehydrocyclization involving the /1-carbon atom of naphthalene gives 4,5-benzindan and 4,5-benzindene ... 

It has been reported that 1 //-bcnz / indene (1), l//-benz[e]indene (2), l//-benz[/g] acenaphthylene (3), and 1 //-cyclopenta[/]-phcnanthrene (4), possessing planar carbon frameworks with a single secondary C(.sy 3)H2 centre, exhibit modest acidity in the gas-phase and in DMSO.1 The origin of their amplified acidity compared with cyclopentane, cyclopentene, and cyclopentadiene is the more pronounced anionic resonance, which distributes the negative charge over the whole planar carbon skeleton via mobile n-electrons. 

In the HMO if> of styrene, the coefficients at the a and / carbon atoms are ca. 0-4 and 0-6 respectively. In the HMO ifi7 of acenaphthylene, the coefficients at carbon atoms 1 and 2 are ca. — 032 and 0-32. Therefore, the directive effect for addition is syn in styrene and anti in acenaphthylene Second, MO calculations may be helpful in new or different systems. With respect to eliminations, Fukui and Fujimoto (1965) used frontier electron theory to provide reactivity indices for two model... 

Although the great majority of petroleum and coal-based pitch materials, as well as model compounds such as polyvinyl chloride, acenaphthylene, decacyclene and polynuclear aromatic hydrocarbons, form anisotropic graphitizable carbons, it is an almost impossible task to predict the type of optical texture of a coke from an elemental analysis of the pitch. The size, shape and reactivity of peri-condensed polynuclear aromatic molecules in the products of pyrolysis of a pitch play a more important role in determining optical texture. 

The reaction schemes of carbonization have also been investigated (11-15). The molecular structure of the carbonization intermediates can influence strongly the optical anisotropy of the resultant coke. The carbonization intermediates have been reported for the pyrolysis of acenaphthylene, which provides a rare example of atmospheric carbonization of a pure organic chemical (11). The carbonization scheme is illustrated in Figure 2. The intermediates II, III, and VI are proposed based on... 

Figure 2. Carbonization scheme for acenaphthylene Reproduced with permission from reference 12. Copyright 1979 IPC Business Press, Ltd.

The - C NMR spectrum for C ) (18 h integration) consists of a single line (Fig. 3n), as required, at 142.68 ppm, and unaltered by proton decoupling. This is significantly down-field from the peaks for the corresponding positions in naphthalene (133.7 ppm), acenaphthylene (128.65 ppm), and benzo(g./i,i,]fluoranthene (126.85,128.05 and 137.75 ppm). This is not unexpected since strain produces downfield shifts which may be attributed to strain-induced hybridisation changes, as shown for example by the C peaks for the bridgehead carbons in tetralin (136.8 ppm), indane (143.9 ppm) and benzcyclobutene (146.3 ppm). ... 

The XH NMR spectrum shows bands in the region 4.0-6.0 ppm (See Table 6). Following the discussion of priority of paths of delocalization of aceheptylene dianion 232 and acenaphthylene dianion 82 also 332 and 342 show that specific paths of delocalization are favoured. While in the neutral structure 33 and 34 the competition is between aromatic and nonaromatic structures, in the respective dianions the competition is between nonaromatic and antiaromatic structures (Fig. 9). From the spectroscopic parameters, i.e., chemical shifts and coupling constants of the bridge protons it can be concluded that the neutral systems are best represented by structures with an aromatic skeleton connected to a virtually isolated double bond. In the charged systems, viz. 332 and 342 it seems that a nonaromatic path of conjugation is preferred to an antiaromatic path (Fig. 9). These considerations are also reflected in the carbon chemical shifts and in their HOMO-LUMO gap (AE) (vide infra) 122). It can be concluded from all these observations that there is a tendency of aromatic systems to remain so and to avoid as much as possible paratropic antiaromatic contributions. 

Nitrogen-15 NMR data of quinolizinium and related compounds are useful criteria for the study of the extent of the delocalization of their n systems. For example, replacement of the central carbon atom of acenaphthylene by nitrogen leads to pyrrolo[2,l,5-chemical reactivity (for example, lack of alkenic character in the 1,2 bond) suggest a delocalized n structure (47), which is supported by the shielding of the nitrogen atom (22.3 ppm with respect to quinolizinium) in the N NMR spectrum of this compound <84JCS(P1)2553>. 

Acenaphthylene reacts with elemental sulfur in DMF at 120°C to give thiophene (Scheme 82) (415) when the reaction was quenched at the early stage, a dihydro-1,4-dithiin, which is a probable intermediate leading to (415), is isolated <89SUL135>. Acenaphthylene also reacts with an S " species, generated by oxidation of a carbon-sulfur electrode, to give (415) in a better yield <94BSF789>. 

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