2-methoxynaphthalene

Structural formula
General
Surname	2-methoxynaphthalene
other names	2-naphthyl methyl ether, β-naphthyl methyl ether Yara-Yara Nerolin old, Jara-Jara, methyl-β-naphthyl-ether
Molecular formula	C 11 H 10 O
Brief description	colorless and odorless crystalline powder
External identifiers / databases
CAS number 93-04-9 EC number 202-213-6 ECHA InfoCard 100.002.013 PubChem 7119 ChemSpider 6852 Wikidata Q2240068
properties
Molar mass	158.20 g mol −1
Physical state	firmly
density	1.064 g cm −3
Melting point	70… 73 ° C
boiling point	272 ... 274 ° C
Vapor pressure	0.01 hPa (25 ° C)
solubility	Practically insoluble in cold water. Slightly soluble in ethanol: 4 g of 2-methoxynaphthalene dissolve in 100 ml of ethanol.
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 319-411 P: 273-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

2-methoxynaphthalene (also called 2-naphthylmethylether or Yara-Yara ) is an organic chemical compound that has the structure of naphthalene and which is derived from 2-naphthol (also called β-naphthol). It is a colorless solid that has been used as a fragrance for over a century, for example in cheap soaps or incense sticks . The smell is reminiscent of orange blossom and thus of the orange blossom oil neroli . That is why 2-methoxynaphthalene - like the similar homologous 2-ethoxynaphthalene - was also marketed as neroline . To distinguish between 2-methoxynaphthalene nerolin I or nerolin old, 2-ethoxynaphthalene nerolin II or nerolin new. The scent of the methyl ether is also described as an acacia note . These substances are substitutes that are not found in nature's fragrant flowers.

history

The first description and characterization of 2-methoxynaphthalene was reported in 1879, with the smell being described as "of pineapple" at the time.

presentation

It is prepared from 2-naphthol and a methylation reagent such as methanol , dimethyl sulfate or diazomethane , methylation using dimethyl sulfate being mentioned in particular. Sulfuric acid is mostly used as a catalyst for the reaction between 2-naphthol and methanol , but molecular sieves can also be used. A synthesis of the Williamson ether synthesis type is also possible. B. from the sodium salt of 2-naphthol, which is methylated by means of halomethane.

properties

Physical Properties

2-methoxynaphthalene is almost insoluble in cold water (only 75.9 mg / liter), but hardly soluble in hot water. Very little dissolves in methanol or ethanol. It is easily soluble in ether, benzene , chloroform, and carbon disulfide . 2-methoxynaphthalene can be distilled with steam. Its enthalpy of formation is −98 kJ mol ⁻¹ , the enthalpy of combustion −5660 kJ mol ⁻¹ .

Chemical properties

The nitration with nitric acid produces 1-nitro-2-methoxynaphthalene.

use

Before World War I, 2-methoxynaphthalene was used to denaturate fatty oils used for industrial purposes because of its clinging odor . In the 1960s, it was used as a flavoring in chewing gum in the USA at a concentration of no more than 11 ppm . It also served as a starting material for the synthesis of the antipyretic drug naproxen , of which 500 kg were made from 2-methoxynaphthalene in 1970. Its main use is as a fragrance in cheap soaps.

safety instructions

Like most organic substances, this ether is also flammable. It is harmful to aquatic organisms. Wear gloves and safety glasses when handling it.

Individual evidence

1. ↑ ^{a b c d} German Chemical Society (Ed.): Beilstein's Handbook of Organic Chemistry . Comprehensive literature up to January 1, 1910. fourth edition. 6 Isocyclic Oxo Compounds. Julius Springer, Berlin 1923, system no. 538, Functional Derivatives of β-Naphthol, p. 640–641 ( online in the Internet Archive ).
2. ↑ ^{a b c d e f} Entry on 2-methoxynaphthalene in the GESTIS substance database of the IFA , accessed on 2017(JavaScript required) .
3. ↑ Data sheet 2-methoxynaphthalene from Sigma-Aldrich , accessed on April 4, 2020 ( PDF ).
4. ^ Yara Yara Safety Data Sheet. Vigon, 2018, accessed April 4, 2020 .  
5. ↑ ^{a b c} Yara Yara - Yara Yara (2-Methoxynaphthalene) Manufacturer from Vadodara. Retrieved April 4, 2020 .  
6. ↑ ^{a b c d} Eduard Gildemeister, Friedrich Hoffmann: The essential oils . Third edition. First volume. Verlag der Schimmel & Co. Aktiengesellschaft, L. Staackmann, Leipzig 1928, III, main components of essential oils, natural and artificial fragrances; Phenols and phenol ethers, β-naphthol ethers, S. 624 ( online in the Internet Archive, English version “The Volatile Oils” from 1913 (Longmans, Green and Co, London) pages 495-496 online in the Internet Archive [accessed on April 4, 2020]): “for perfuming cheap home and Toilet soaps a lot of used products "
7. ↑ ^{a b} Walther Schrauth, C. Deite: Handbook of soap manufacturing . According to the handbook by Dr. C. Deite. fifth edition. Julius Springer, Berlin 1921, E. The fine soaps, I The raw materials for fine soap production, 3. The fragrances for perfuming fine soaps, p. 479-480 ( online in the Internet Archive ): "for perfuming cheap household and toilet soaps "
8. ↑ ^{a b c} 2-methoxynaphthalene. In: Lexicon of Chemistry. Spektrum Akademischer Verlag, Heidelberg, 1998, accessed on April 4, 2020 .  
9. ^ C. Marchetti: Sopra alcuni derivati ​​dei Naftoli . In: Gazzetta chimica Italiana . tape 9 . Michele Amenta, Palermo 1879, p. 544-545 ( online on Internet Archives , abstract from Annual Report on Advances in Chemistry online at the Hathi Trust Digital Library).
10. ↑ T.Yu. Stoylkova, CD Chanev, HT Lechert, CP Bezouhanova: Methylation of 2-naphthol over molecular sieves . In: Catalysis Letters . tape 69 , no. 1/2 , 2000, pp. 109-112 , doi : 10.1023 / A: 1019061604671 ( springer.com ).
11. ↑ beta-naphthyl methyl ether, 93-04-9. In: thegoodscentscompany.com. Retrieved April 4, 2020 .  
12. ↑ M. Colomina, MV Roux, C. Turrion: Thermochemical properties of naphthalene compounds IV. Enthalpies of combustion and formation of 2-methoxynaphthalene, 2-ethoxynaphthalene, and 2,3- and 2,7-dihydroxynaphthalenes . In: The Journal of Chemical Thermodynamics . tape 8 , no. 9 September 1976, p. 869-872 , doi : 10.1016 / 0021-9614 (76) 90164-6 ( elsevier.com ).
13. ↑ Denaturation of fatty oils . Official ordinances and decrees. In: Journal for Analytical Chemistry . tape  52 , no. December 12 , 1913, p. 4-6 , doi : 10.1007 / BF01554318 ( springer.com ).
14. ^ Food Protection Committee, Food and Nutrition Board: Chemicals Used in Food Processing . Ed .: National Academy of Sciences, National Research Council. Publication 1274. Washington DC 1965, LCCN  65-060045 , pp. 165 ( limited preview in Google Book search).
15. ^ Peter J. Harrington, Eric Lodewijk: Twenty Years of Naproxen Technology . In: Organic Process Research & Development . tape 1 , no. 1 , January 1997, p. 72-76 , doi : 10.1021 / op960009e ( acs.org [accessed April 3, 2020]).