JPS5842234B2 - You can't get enough of this. - Google Patents

Description

[Detailed description of the invention] The present invention relates to an odorant for fuel gas.

More specifically, the present invention relates to an odorant for fuel gas having a low sulfur content, which is characterized in that a small amount of γ-alkylthiopropyl alcohol is blended as an odor strength enhancing amplification agent.

Nowadays, fuel gas, whether it is city gas or liquefied petroleum gas, is made into gas-like gases so that in the event of a leak, it can be detected quickly and easily using the sense of smell, in order to prevent disasters such as poisoning and explosions. It is odorized with an odorant that has a bad odor.

The main odorant components are single or appropriate mixtures of sulfur compounds such as chain or cyclic thioalcohols having 2 to 5 carbon atoms and chain or cyclic thioethers.

The reason is that the odor of these compounds is most similar to gas odor (tetrahydrothiophene C, a cyclic thioether currently used as an odorant for city gas).
4H3S etc. are the odor components of odorous pure coal gas that does not require odor addition) ■ Can exert odor effect in small amounts (in the case of city gas, 20-5 per 1 liter gas)
0■, 4040- per 1ttIrL for liquefied petroleum gas
5O■ This is due to reasons such as the low price.

However, recently, regulations on sulfur oxides have been becoming stricter from the standpoint of air pollution and other so-called pollution, and against this background, fuel gas is also being sourced from liquefied natural gas (city gas) or refined. We are beginning to move toward cleaner gas, such as increasing the sulfur content and keeping the sulfur content as low as possible (liquefied petroleum gas).

With regard to lively odorants, attention has been paid to the fact that the addition of odorants increases the sulfur content in gas (although it is only a few ppm or less), and low-sulfur or sulfur-free odorants have begun to be desperately needed. Ta.

In response to this trend, various attempts have been made to use unsaturated acid esters, aldehydes, ketones, etc. as odor-producing agents, but these do not necessarily satisfy all conditions such as stability over time, odor quality, and price. There is currently no such thing, and efforts are currently being made to limit the amount of sulfur compounds as the main odor-producing agent as much as possible.

However, at the same time, this would weaken the customization of sulfur compound odors, which are most suitable as warning odors for detection, and this is not necessarily a welcome direction from the standpoint of safety and disaster prevention.

The present inventors have continued to research low-sulfur odorants that meet the purpose of reducing sulfur content, do not change odor quality, and do not reduce odor intensity. γ-alkylthiopropyl alcohol (R-S -CH2CH,C
When H20H) is used together with thioalcohols, thioethers, etc., which are the main ingredients of conventional odorants, it exhibits an extremely large synergistic effect, resulting in significant sensitization and amplification of odor intensity, and the required amount of addition. It was confirmed that only 0.5 to 1% of the odorant composition is sufficient.

γ-Alkylthiopropyl alcohol is R-8・CH2
・It is a type of thioalcohol with the structure CH2・CH20H, but its odor is similar to soy sauce (R=CH
3) Or potato-like or garlic-like (R=C2H5,
C3H7, C3H1□) or also butter uniform (R= C4
H9) etc. (γ-methylopropyl alcohol of R-CH3 is known as a flavor for reinforcing powdered soy sauce), and therefore these compounds were selected as odorant materials. There wasn't any.

However, the present inventors focused on the fact that these γ-alkylthiopropyl alcohols have a considerably low odor detection threshold, even though they have a low odor quality, and conducted experiments as part of sulfur-based odor-producing materials that can produce high odor intensity at low concentrations. Although these compounds are completely unsuitable as gas odorants due to their odor quality, conventional odor-producing main agents such as thioalcohol, which are diluted with solvents to about 1/4 to 115 When a trace amount of 0.5 to 1% is added to thioether, etc., the food-like odor of the soy sauce, potato, or butter is hardly felt, and on the contrary, the thioalcohol, which is the main ingredient, It was confirmed that there is a synergistic effect that enhances and amplifies the odor intensity of thioether to almost the same level as that when used without dilution.

Therefore, by blending a small amount of this series of γ-alkylthiopropyl alcohols as an odor amplification enhancer, various types of γ-alkylthiopropyl alcohols can be produced that have an extremely low sulfur content of 1/4 to 115 times that of conventional alcohols, yet have sufficient odor intensity and optimal substance. It has the characteristic that odor can be easily applied.

A detailed explanation will be given below using experimental examples.

However, the present invention is not limited to this.

Experimental example 1 (based on liquefied petroleum gas odorization method) Capacity 41
Prepare four experimental LPG (liquefied petroleum gas) cylinders,
Add to this the previously prepared ■γ-methylthiopropyl alcohol 0.5% solution (using methanol as a solvent), ■ethyl mercaptan, ■20% solution of ethyl mercaptan (using n-hexane as a solvent), and ■ethyl full cuff 2.
A total of four samples, each containing 20% methanol, 10% methanol, and 69.5% n-hexane, were injected into each 35cm microsyringe, and immediately 9cm each cylinder was filled with odorless propane.

(This corresponds to the addition rate of 35 g per LPG lm) Next, this odorized gas was released into an odorless chamber with a volume of 8 m' in an amount of 80 g (Note 1), and after stirring with a stirring propeller, a panel of 8 experienced people checked the odor intensity and substance through the sniffing window. A sensory test was conducted and the following results were obtained.

The criteria for judging odor intensity is based on a certain place's 6-step display method (Note 2).Experiment Example 2 (Odorization method for city gas) 1% solutions (solvent n-hexane) of the four samples used in Experiment Example 1 were prepared. , each in an odor bottle of 120 cm (this amount per 401 cm of air is exactly the gas 1 gas which is the odor standard for city gas)
(equivalent to 0.03 g per m°) was injected, air was flowed after sealing the container, and a flow meter (instead of gas) was used to accurately send 407 into the odorless chamber, confirming that there was no sample remaining in the odorized bottle. After that, the air flow was stopped, the inside of the odorless room was stirred, and a sensory test was conducted in the same manner as in Experimental Example 1.

The results are as follows. Experimental Example 3 The effect of adding γ-alkylthiopropyl alcohol to various thioalcohols, thioethers, etc. was tested in exactly the same manner as in Experimental Examples 1 and 2, and the following results were obtained.

Example 1 10 parts of tertiary butyl mercaptan, 10 parts of isopropyl mercaptan, 0.5 part of γ-methylthiopropyl alcohol, 10 parts of methanol, 69 parts of n-hexane
．． A product is prepared by mixing 5 parts by weight.

Example 2 10 parts of ethyl mercaptan, 15 parts of dimethyl sulfide
1 part of gamma-propylthiopropyl alcohol, 10 parts of methanol, and 64 parts of n-hexane in a weight ratio to prepare a product.

Example 3 5 parts of tetrahydrothiophene, 10 parts of tertiary butyl mercaptan, 1 part of tertiary amyl mercaptan
A product is prepared by mixing 0 parts of γ-amylthiopropyl alcohol, 1 part of methanol, and 64 parts of n-hexane in a weight ratio.

Example 4 A product is prepared by mixing 25 parts of tetrahydrothiophene, 1 part of γ-methylthiopropyl alcohol, 10 parts of methanol, and 64 parts of normal hexane in a weight ratio.

Claims (1)

[Scope of Claims] 1 Chain and cyclic thioalcohols having 2 to 10 carbon atoms and chain and cyclic thioethers having 2 to 10 carbon atoms, singly or in any mixture, as odor-producing active ingredients; γ-Alkylthiopropyl alcohol with 1 to 5 carbon atoms [R-8-C■2CH2
An odorant for fuel gas characterized by adding a small amount of CH20H (R is C1 to C5 alkyl).