Menthol Solutions

Dissolve menthol in peppermint oil at 25°C by slow stirring in another mixing vessel. Continue stirring until the solution becomes clear. Transfer the clean menthol solution (step 5) into step 4 while stirring at the set speed. Continue stirring for 1 hour. 

A 40-year-old woman with no personal or family history of asthma had dyspnea, wheezing, and nasal symptoms for 2 years whenever she used toothpaste and/or ingested mint confections. She had no history of aspirin sensitivity, and a challenge test with a menthol solution diluted in alcohol ruled out any possibihty that the asthma had been caused by preservatives, dyes, or other additives. 

Haidl P, Kemper P, Butnarasu SJ et al (2001) Does the inhalation off L-menthol solution in the premedication for fiberoptic bronchoscopy affect coughing and the sensation of dyspnoea Pneu-mologie 55 115-119... 

Mark off the isoprene units in citronellal and menthol. Solution... 

Piperitone is of considerable technical im portance. It is a colourless oil of a pleasant peppermint-like smell. (-)-Piperilone has b.p. 109-5-110-5 C/I5mm. Piperitone yields thymol on oxidation with FeCl. On reduction with hydrogen in presence of a nickel catalyst it yields menthone. On reduction with sodium in alcoholic solution all forms of piperitone yield racemic menthols and womenthols together with some racemic a-phel)andrene. 

It forms a characteristic benzoic ester, Cj HjgO. CO. CgH, melting at 54°. This is a useful compound for identifying menthol and may be obtained by heating menthol with the theoretical amount of benzoic acid, in a sealed tube to 170° excess of acid is removed by shaking with a boiling solution of sodium carbonate, and the ester is crystallised from alcohol. Menthol forms a phenylurethane, melting at 111° to 112°. 

A 5-1. three-necked round-bottomed flask is fitted with a mechanical stirrer (Note 1) and a reflux condenser bearing a calcium chloride tube. A solution of 400 g. (2.56 moles) of -menthol (crystals, m.p. 41-42°) in 11. of dry toluene (Note 2) is placed in the flask, and to it is added 70 g. (3.04 gram atoms) of clean... 

P-parinaric acid, physical properties, 5 33t P-pentenoic acid, physical properties, 5 3 It P-peroxylactones, 18 484 Beta phase titanium, 24 838 in alloys, 24 854-856 properties of, 24 840, 941 P-phellandrene, 24 493 P-picoline, 21 110 from acrolein, 1 276 uses for, 21 120 P-pinene, 3 230 24 496-497 major products from, 24 478 /-menthol from, 24 522 as natural precursor for aroma chemicals, 3 232 terpenoids from, 24 478-479 P-propiolactone, polymerization of, 14 259 P-quartz solid solution, 12 637—638 Beta ratio, in filtration, 11 329—330 Beta (P) rays, 21 285 P-scission reactions, 14 280-281 P-skytanthine, 2 101 P-spodumene solid solution, 12 638-639 P-sulfur trioxide, 23 756 P-sultones, 23 527 P-tocopherol, 25 793 P-tocotrienol, 25 793 P-vinylacrylic acid, physical properties, 5 33t... 

The solution of butylllthium In hexane was purchased from the Aldrich Chemical Company, Inc. and standardized with menthol and phenanthrollne before use. 

Separation of catalysts from high-value products such as fine chemicals or pharmaceuticals is often accomplished by precipitating the catalyst from the product solution. Recycling of these catalysts is feasible, provided that they do not decompose. In industry, catalyst recovery by means of catalyst precipitation is applied only in relatively small batch processes. An example of such a process is the production of (—)-menthol (id) in which an Rh-BINAP isomerization catalyst converts the allylic amine substrate into (R)-citronellal (after hydrolysis of the enamine) in high yield (99%) and with high enantioselectivity (98.5% ee). After distillation of the solvent (THF) and product, the catalyst is recovered from the residue by precipitation with -heptane. 

Chiral furanones (butanolides) such as 191 have been used as dipolarophUes in various 1,3-dipolar cycloadditions. The chiral 4-substituted butanolide 190 was prepared from 191 and the chiral auxiliary menthol (Scheme 12.55) (310,311). The single diastereomer 191 is obtained by crystallization and epimerization of the other diastereomer, as the amount of 191 in solution decreases. 1,3-Dipolar... 

Preexposure to menthol and capsaicin can desensitize the response to other stimuli, i.e. the thermal response to a warm solution or the irritation upon a second application of capsaicin (26,27). After capsaicin desensitization, the nerves no longer respond to burning or stinging but still give sensations of numbness or warmth. This effect is most noticeable upon further stimulation with capsaicin and less for the irritants, cinnamic aldehyde and NaCl. This sensitization and the fact that these sensations build in intensity on repeat application differentiate them from the "basic tastes", which adapt to the sensation on repeated application. 

FIGURE 11. Headspace analysis of solutions of menthol [- -], carvone [- -] and cineole [-A-] in SLS (initial concentration, SLS=1.0%, flavorant=0.0075%) showing differences in release of flavor compounds according to their solubility in SLS micelles [Adapted from ref. 77]. 

Q. What is the boiling point of a solution containing 45.2 g of menthol (CjqH2qO) dissolved in 350 g of acetic acid ... 

A. 120.6°C. The problem asks for the boiling point of the solution, so you know that first you have to calculate the boiling point elevation. This means you need to know the molality of the solution and the value of the solvent (acetic acid). Table 13-2 tells you that the of acetic acid is 3.07. To calculate the molality, you must convert 45.2 g of menthol to moles ... 

Stir well after each addition of acid. Dissolve menthol, flavors, and orange oil in alcohol add mixture to solution from step above with good stirring. 

In a separate container add alcohol and mix and dissolve aniseed oil, eucalypus oil, menthol, and polyethylene glycol 400 to obtain a clear solution. 

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