91-57-6

Usage

Chemical Properties

1-Methylnaphthalene and 2-methylnaphthalene are naphthalenerelated compounds. 1-Methylnaphthalene is a clear liquid and 2- methylnaphthalene is a solid. Insoluble inwater; soluble in alcohol and ether. Combustible. both can be smelled in air and in water at very low concentrations. The taste and odor of 2-methylnaphthalene have not been described. Its presence can be detected at a concentration of 10 ppb in air and 10 ppb in water.

Uses

Different sources of media describe the Uses of 91-57-6 differently. You can refer to the following data:
1. 2-methylnaphthalene are used to make other chemicals such as dyes, insecticides, Organic synthesis and resins. Pure 2-methylnaphthalene is a component used in the manufacture of vitamin K and the insecticide carbaryl (1-naphthyl-N-methylcarbamate) (HSDB, 2002).Methylnaphthalene (CASRN 1321-94-4) refers to a mixture of approximately two-thirds 2-methylnaphthalene and one-third 1-methylnaphthalene (CASRN 90-12-0). Methylnaphthalene is manufactured from coal tar through the extraction of heteroaromatics and phenols. Distillation of methylnaphthalene removes 1-methylnaphthalene, leaving 2-methylnaphthalene. Mixtures containing 2-methylnaphthalene are used in the formulation of alkyl-naphthalenesulfonates (used for detergents and textile wetting agents), chlorinated naphthalenes, and hydronaphthalenes (used as solvents).
2. The main uses of methylnaphthalene are as a raw material for dyestuff dispersants and heat transfer oils, and as a solvent for agricultural chemical. It has been used as an indicator of smoke exposure in food and packaging materials.

Production Methods

Alkylnaphthalenes are formed as pyrolysis products in cigarette smoke. Some have been identified in commercial carbon paper. They are also the major components of the C10–C13 alkylnaphthalene concentrate fraction, which distills at 400–500
F. A C11–C12 petroleum mixture of reformates that contained about 23% alkylnaphthalenes caused skin and eye effects. The toxicity of the alkylnaphthalenes to marine species is greater than that of the alkylbenzenes (85). The toxicity and the bioaccumulation increase with molecular weight. Nocardia cultures, isolated from soil, preferentially oxidized alkylnaphthalenes when methylated in the two positions. Methylnaphthalene can occur as the 1- or 2-, the alpha or the beta isomer. 1-Naphthalene, a flammable solid, has also been identified in the wastewater of coking operations, and in textile processing plants. Methylnaphthalene is used as a component in slow-release insecticides and in mole repellents. Workplace exposures to 18–32 mg/m3 for 2-methylnaphthalene have been reported.

Definition

ChEBI: A methylnaphthalene carrying a methyl substituent at position 2.

Synthesis Reference(s)

The Journal of Organic Chemistry, 54, p. 2142, 1989 DOI: 10.1021/jo00270a024Synthesis, p. 1036, 1982 DOI: 10.1055/s-1982-30054Tetrahedron Letters, 36, p. 6051, 1995 DOI: 10.1016/0040-4039(95)01240-I

Air & Water Reactions

Insoluble in water.

Reactivity Profile

2-Methylnaphthalene is incompatible with strong oxidizing agents. 2-Methylnaphthalene is also incompatible with peroxides and oxygen.

Hazard

Lower respiratory tract irritant and lungdamage. Questionable carcinogen.

Fire Hazard

2-Methylnaphthalene is combustible.

Carcinogenicity

The carcinogenic potential of 1- and 2-methyl was investigated in B6C3F1 mice. Female and male mice were given methylnaphthalene in their diets for 81 weeks. The results indicated that 1-methyl was a possible weak carcinogen in the lung of male but not female mice whereas 2-methyl did not possess unequivocal carcinogenic potential in these mice.

Source

Detected in distilled water-soluble fractions of No. 2 fuel oil (0.42 mg/L), jet fuel A (0.17 mg/L), diesel fuel (0.27 mg/L), military jet fuel JP-4 (0.07 mg/L) (Potter, 1996), new motor oil (0.42 to 0.66 μg/L), and used motor oil (46 to 54 μg/L) (Chen et al., 1994). Present in diesel fuel and corresponding aqueous phase (distilled water) at concentrations of 3.5 to 9.0 g/L and 180 to 340 μg/L, respectively (Lee et al., 1992). Schauer et al. (1999) reported 2-methylnaphthalene in diesel fuel at a concentration of 980 μg/g and in a diesel-powered medium-duty truck exhaust at an emission rate of 511 μg/km. Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from Gainesville, FL with individual fractions of three individual petroleum products at 24–25 °C for 24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method 625. Average 2-methylnaphthalene concentrations reported in water-soluble fractions of unleaded gasoline, kerosene, and diesel fuel were 256, 354, and 267 μg/L, respectively. California Phase II reformulated gasoline contained 2-methylnaphthalene at a concentration of 1.33 g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were approximately 1.00 and 50.0 mg/km, respectively (Schauer et al., 2002). Based on laboratory analysis of 7 coal tar samples, 2-methylnaphthalene concentrations ranged from 680 to 42,000 ppm (EPRI, 1990). Detected in 1-yr aged coal tar film and bulk coal tar at concentrations of 25,000 and 26,000 mg/kg, respectively (Nelson et al., 1996). A high-temperature coal tar contained 2-methylnaphthalene at an average concentration of 1.23 wt % (McNeil, 1983). Lee et al. (1992a) equilibrated eight coal tars with distilled water at 25 °C. The maximum concentration of 2-methylnaphthalene observed in the aqueous phase is 1.4 mg/L. Detected in wood-preserving creosotes at a concentration of 3.0 wt % (Nestler, 1974). Typical concentration of 2-methylnaphthalene in a heavy pyrolysis oil is 7.4 wt % (Chevron Phillips, May 2003). An impurity identified in commercially available acenaphthene (Marciniak, 2002). Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rates of 2-methylnaphthalene were 15.0 mg/kg of pine burned, 9.61 mg/kg of oak burned, and 5.69 mg/kg of eucalyptus burned.

Environmental fate

Biological. 2-Naphthoic acid was reported as the biooxidation product of 2-methylnaphthalene by Nocardia sp. in soil using n-hexadecane as the substrate (Keck et al., 1989). Dutta et al. (1998) investigated the degradation of 2-methylnaphthalene using a bacterial strain of Sphingomonas paucimobilis grown on phenanthrene. Degradation products identified using GC-MS were 4- methylsalicylate, 2-methylnaphthoate, and 1-hydroxy-2-methylnaphthoate. Estimated half-lives of 2-methylnaphthalene (0.6 μg/L) from an experimental marine mesocosm during the spring (8–16 °C), summer (20–22 °C), and winter (3–7 °C) were 11, 1.0, and 13 d, respectively (Wakeham et al., 1983). Photolytic. Fukuda et al. (1988) studied the photodegradation of 2-methylnaphthalene and other alkylated naphthalenes in distilled water and artificial seawater using a high-pressure mercury lamp. Based upon an experimentally rate constant of 0.042/h, the photolytic half-life of 2- methylnaphthalene in water is 16.4 h. Phousongphouang and Arey (2002) investigated gas-phase reaction of naphthalene with OH radicals in a 7-L Teflon chamber at 25 °C and 740 mmHg containing 5% humidity. The rate constant for this reaction was 4.86 x 10-11 cm3/molecule?sec. Chemical/Physical. An aqueous solution containing chlorine dioxide in the dark for 3.5 d at room temperature oxidized 2-methylnaphthalene into the following: 1-chloro-2-methylnaphthalene, 3-chloro-2-methylnaphthalene, 1,3-dichloro-2-methylnaphthalene, 3-hydroxymethylnaphthalene, 2-naphthaldehyde, 2-naphthoic acid, and 2-methyl-1,4-naphthoquinone (Taymaz et al., 1979).

Purification Methods

Fractionally crystallise repeatedly from its melt, then fractionally distil under reduced pressure. It has been crystallised from *benzene and dried under vacuum in an Abderhalden pistol. It can be purified via its picrate (m 114-115o) or better via the 1,3,5-trinitrobenzene complex as for 1-methylnaphthalene (above). [Beilstein 5 IV 1693.]

InChI:InChI=1/C11H10/c1-9-6-7-10-4-2-3-5-11(10)8-9/h2-8H,1H3

Upstream product

• 110-89-4 piperidine 
• 2586-62-1 1-bromo-2-methylnaphtalene 
• 767-04-4 1-(1,3-dioxolan-2-yl)propan-2-one 
• 6921-34-2 benzylmagnesium chloride 
• 613-46-7 2-naphthalenecarbonitrile 
• 91-20-3 naphthalene 
• 74-87-3 methylene chloride 
• 110-82-7 cyclohexane 
• 75-34-3 1,1-dichloroethane 
• 115-10-6 Dimethyl ether 
• 75-09-2 dichloromethane 
• 10240-08-1 4-methyl-1-naphthol 
• 2049-94-7 (3-methylbutyl)benzene 
• 7469-77-4 2-methylnaphthalen-1-ol 

Downstream Products

• 2506-41-4 1-chloromethylnaphthalene 
• 939-26-4 2-bromomethylnaphthyl bromide 
• 38119-04-9 2-(2-methyl-[1]naphthoyl)-benzoic acid 
• 69750-34-1 2-methyl-6-propanoyl naphthalene 
• 42200-07-7 1-benzyl-2-methyl-naphthalene 
• 4919-69-1 (2-methylnaphthalen-1-yl)(phenyl)methanone 
• 73408-33-0 (2-methylnaphthalen-1-yl)(4-methylphenyl)methanone 
• 73408-31-8 (2-methylnaphthalen-1-yl)(o-tolyl)methanone 
• 793724-78-4 2-(2-methyl-[1]naphthyl)-benzoic acid 
• 53-70-3 dibenzo[a,h]anthracene 
• 226-88-0 benzo[a]naphthacene 
• 73408-32-9 (2-methylnaphthalen-1-yl)(m-tolyl)methanone 
• 84029-69-6 6-tert-butyl-2-methylnaphthalene 
• 1817-67-0 (S)-4-methyl-2-(1-phenylethyl)phenol 

Relevant academic research and scientific papers

Negative correlations between cultivable and active-yet-uncultivable pyrene degraders explain the postponed bioaugmentation

Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbons (PAHs), but suffers from unsatisfactory performance in engineering practices, which is hypothetically explained by the complicated interactions between indigenous microbes and introduced degraders. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium (Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira) by magnetic-nanoparticle mediated isolation (MMI) from soils. Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, whilst increased by 30.17% by the active pyrene degrading consortium. Pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP) were enriched in MMI isolates and positively correlated with pyrene degradation efficiency. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas both phthalate and salicylate pathways were observed in the active pyrene degrading consortium. The results indicated that the uncultivable pyrene degraders were suitable for bioaugmentation, rather than cultivable Sphingomonas sp. YT1005. The negative correlations between Sphingomonas sp. YT1005 and the active-yet-uncultivable pyrene degraders were the underlying mechanisms of bioaugmentation postpone in engineering practices.

Ceramic boron carbonitrides for unlocking organic halides with visible light

Photochemistry provides a sustainable pathway for organic transformations by inducing radical intermediates from substrates through electron transfer process. However, progress is limited by heterogeneous photocatalysts that are required to be efficient, stable, and inexpensive for long-term operation with easy recyclability and product separation. Here, we report that boron carbonitride (BCN) ceramics are such a system and can reduce organic halides, including (het)aryl and alkyl halides, with visible light irradiation. Cross-coupling of halides to afford new C-H, C-C, and C-S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C-X (carbon-halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only for half reactions, like reduction reactions with a sacrificial agent, but also redox reactions through oxidative and reductive interfacial electron transfer. The BCN photocatalyst shows tolerance to different substituents and conserved activity after five recycles. The apparent metal-free system opens new opportunities for a wide range of organic catalysts using light energy and sustainable materials, which are metal-free, inexpensive and stable. This journal is

Iodine-catalyzed alcohol disproportionation method

The invention relates to the technical field of catalysis, in particular to an iodine-catalyzed alcohol disproportionation method which comprises the following steps: sequentially adding alcohol, iodine and a solvent into a high-temperature and high-pressure reaction kettle, introducing a certain amount of nitrogen, conducting reacting for a certain time, collecting an organic phase after the reaction is ended, and conducting fractionating to obtain corresponding alkane and aldehyde/ketone. Alcohol disproportionation is efficient and atom-economical conversion without any additional oxidizing agent and reducing agent, and hydrocarbon and aldehyde/ketone molecules which are easy to separate can be formed at the same time. Meanwhile, the method has wide functional group tolerance, various substrate samples including aryl alcohol derivatives, heterocyclic alcohol derivatives, allyl alcohol derivatives and dihydric alcohol are tested, and the result shows that most of the substrate samples show good or extremely good yield.

Chemoselective Deoxygenation of 2° Benzylic Alcohols through a Sequence of Formylation and B(C6F5)3-Catalyzed Reduction

A sequence of formylation and B(C6F5)3-catalyzed reduction of the resulting formate with Et3SiH enables the chemoselective deoxygenation of secondary benzylic alcohols. Primary benzylic and tertiary non-benzylic alcohols are not reduced by this protocol. The formyl group fulfills a double role as activator and self-sacrificing protecting group. The deoxygenation of these formates is fast and can be carried out in the presence of other potentially reducible groups. Neighboring-group participation was found in the deoxygenation of certain diol motifs.

Chromium-Catalyzed Reductive Cleavage of Unactivated Aromatic and Benzylic C-O Bonds

Reductive cleavage of aromatic and benzylic C-O bonds by chromium catalysis is reported. This deoxygenative reaction was promoted by low-cost CrCl 2precatalyst combined with poly(methyl hydrogen siloxane) as the mild reducing agent, providing a strategy in forming reduced motifs by cleavage of unactivated C-O bonds. A range of functional groups such as bromide, chloride, fluoride, hydroxyl, amino, and alkoxycarbonyl can be retained in the reduction.

Metal-Free Heterogeneous Semiconductor for Visible-Light Photocatalytic Decarboxylation of Carboxylic Acids

A suitable protocol for the photocatalytic decarboxylation of carboxylic acids was developed with metal-free ceramic boron carbon nitrides (BCN). With visible light irradiation, BCN oxidize carboxylic acids to give carbon-centered radicals, which were trapped by hydrogen atom donors or employed in the construction of the carbon-carbon bond. In this system, both (hetero)aromatic and aliphatic acids proceed the decarboxylation smoothly, and C-H, C-D, and C-C bonds are formed in moderate to high yields (35 examples, yield up to 93%). Control experiments support a radical process, and isotopic experiments show that methanol is employed as the hydrogen atom donor. Recycle tests and gram-scale reaction elucidate the practicability of the heterogeneous ceramic BCN photoredox system. It provides an alternative to homogeneous catalysts in the valuable carbon radical intermediates formation. Moreover, the metal-free system is also applicable to late-stage functionalization of anti-inflammatory drugs, such as naproxen and ibuprofen, which enrich the chemical toolbox.

Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant

A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.

Synthesis of renewable alkylated naphthalenes with benzaldehyde and angelica lactone

Herein, we report a new route for the synthesis of renewable alkylated naphthalenes (ANs) with benzaldehyde and angelica lactone, two platform compounds that can be derived from lignocellulose.

Preliminary investigations on the catalytic hydrogenation of polycyclic aromatic hydrocarbons via WGSR

The water-gas shift reaction (WGSR) is a crucial reaction in the direct liquefaction of lignite in a syngas (CO + H2) system. In this study, anthracene was utilized as a polycyclic model compound of lignite, to which hydrogen is donated by the H2/D2 produced from CO and H2O/D2O via the WGSR. The results show that the model compound of the polycyclic aromatic hydrocarbon in coal (anthracene) undergoes partial cracking and polycondensation under non-hydrogen-donor conditions at 400 °C. In addition, WGSR catalyzed by NiO can generate hydrogen for the hydrogenation of anthracene. Comparing the mass spectra of deuterated products with those of conventional hydrogenation products by isotope labeling, the alkyl side chain positions of toluene, 1,4-xylene, methylnaphthalene, 1,1-diphenylethylene, methylanthracene and other compounds are prone to deuteration, enabling speculation of the main hydrogenation route of anthracene, which provides theoretical support for the catalytic hydrogenation in direct liquefaction of lignite in a syngas (CO + H2) system.

Arylketones as Aryl Donors in Palladium-Catalyzed Suzuki-Miyaura Couplings

Herein, we report the arylation, alkylation, and alkenylation of aryl ketones via a palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. The use of the pyridine-oxazoline ligand is the key to the cleavage of the unstrained C-C bond. The late-stage arylation of aryl ketones derived from drugs and natural products demonstrated the synthetic utility of this protocol.