Sulphur-free gas odorant

Abstract

The present invention relates to a sulphur-free odorizing composition to be added into liquefied petroleum gas (LPG) in order to allow the user to sense any leakage in case of LPG leakages which might occur in the area of utilization.

Claims

1. A sulfur-free gas odorant composition for liquefied petroleum gas, comprising ethyl acrylate, isovaleraldehyde and dimethyl selenide.

2. A sulphur-free gas odorant composition according to claim 1 comprising methyl acrylate.

3. A sulphur-free gas odorant composition according to claim 1, comprising 0-50% methyl acrylate, 10-40% ethyl acrylate, 25-75% isovaleraldehyde, 2-10% dimethyl selenide by weight.

4. A sulphur-free gas odorant composition according to claim 1, comprising 10-40% ethyl acrylate, 25-75% isovaleraldehyde, 2-10% dimethyl selenide by weight.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 is the reaction steps in the In Vivo metabolism of dialkyl disulfides.

DETAILED DESCRIPTION

(2) The odorant composition disclosed consists of different concentrations of isovaleraldehyde, methyl acrylate, ethyl acrylate and selenium compounds; preferably, dimethyl selenide compound. Particularly, the composition is free of sulphur. Odorants containing sulphur compounds and SO.sub.2 gases resulting from combustion thereof in vehicle engine cylinders and gas furnaces, cause air pollution, which may result in respiratory tract diseases. When exposed to high amounts, sulphurous compounds may result in molecular damages especially for living creatures. For vehicles that use Liquefied Petroleum Gas, sulphurous compounds cause corrosion and accumulation in the metal and plastic parts, which shortens the life of the material. On the other hand, since the inventive sulphur-free odorant has an oxygenized organic compound structure, the CO.sub.2 and H.sub.2O resulting from combustion do not harm human health. With the present invention, isovaleraldehyde, ethyl acrylate and methyl acrylate compounds along with selenol compounds are used instead of sulphur compounds. Selenol compounds such as dimethyl selenide compound increase the efficiency of combustion reactions by inhibiting the aromatization reactions which cause coke formation during combustion. Selenol compounds added into LPG as odorant prevent the formation and accumulation of soot in the engine cylinder blocks during combustion reactions. The chemical structures of methyl acrylate, ethyl acrylate and isovaleraldehyde are given in Formula 1, Formula 2 and Formula 3, respectively.

(3) ##STR00001##

(4) Selenium compounds to be used are selected from dimethylselenide shown in Formula 4,

(5) ##STR00002##
dimethyl diselenide shown in Formula 5,

(6) ##STR00003##
diethyl selenide shown in Formula 6,

(7) ##STR00004##
diphenyl selenide shown in Formula 7,

(8) ##STR00005##
diphenyl diselenide shown in Formula 8, or

(9) ##STR00006##
ethyl selenol shown in Formula 9.

(10) ##STR00007##

(11) In the illustrative embodiments, selenium compound is selected preferably as dimethyl selenide. In Table 1, physical characteristics of methyl acrylate, ethyl acrylate, isovaleraldehyde and dimethyl selenide compounds are given.

(12) TABLE-US-00002 TABLE 1 Boiling Melting Odor Vapor pressure Point Point threshold (mmHg Compound ( C.) ( C.) value (ppbv) @ 20 C.) Methyl acrylate 80.0 76 14 67.5 Ethyl acrylate 99.4 72 0.5 31 Isovaleraldehyde 90 51 0.1-2 30 Dimethyl selenide 57-58 238

(13) Isovaleraldehyde is available in the nature in more than one hundred eighty plants, including foods like banana, apple, carrot, cacao, and coffee. Furthermore, in the food industry, aroma of these plants is also used in amino acids production in medical applications. It is used in pharmaceutical industry for anti-viral protection and central nervous system disease drugs and as excipient.

(14) The odorant consists of different concentrations of mixtures of isovaleraldehyde, methyl acrylate, ethyl acrylate and dimethyl selenide chemicals. In this respect, the odorant is suitable for Liquefied Petroleum Gas chemically and physically and it is completely sulphur-free. Therefore, air pollution arising from sulphur and resultant respiratory tract diseases as well as problems arising from sulphur accumulation in vehicles will be eliminated.

(15) Selenium forms weaker -bonds than sulphur. Compared to sulphurous compounds, these bonds break more easily in selenium compounds and they liberate. Selenium easily oxides into Se(IV).

(16) Organoselenium compounds may be easily attacked by nucleophile. This prevents soot accumulation in a long period of time by delaying polymerization to which heavy hydrocarbon structures, which are possibly available in LPG and cause serious problems in engine parts depending on long term utilization, may be subjected over time depending on combustion.

(17) Carbon-selenium bonds of SeC, H.sub.2Cse and H.sub.3CseH compounds are defined as 1.676 , 1.756 and 1.959 , respectively (Determan and Wilson, 2013). However, the carbon-sulphur bond which is approximately 1.39-1.40 in sulphurous compounds renders the structure more robust (Schreiner et al., 2009). 234 kJ/mol energy is required to break CSe bonds while CS bonds require an energy level of 272 kJ/mol (Krief, 1988; Patai et al., 1986; Paulmier, 1986; Freudendahl, 2009 and Wallschlger, 2010).

(18) Illustrative compounds are given below.

(19) TABLE-US-00003 Example 1 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Methyl acrylate 40 4 Ethyl acrylate 50 Iso valeraldehyde 50 Dimethyl selenide 10

(20) TABLE-US-00004 Example 2 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Ethyl acrylate 25 3 Iso valeraldehyde 70 Dimethyl selenide 5

(21) TABLE-US-00005 Example 3 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Methyl acrylate 5 3 Ethyl acrylate 20 Iso valeraldehyde 70 Dimethyl selenide 5

(22) TABLE-US-00006 Example 4 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Methyl acrylate 10 3 Ethyl acrylate 20 Iso valeraldehyde 60 Dimethyl selenide 10

(23) TABLE-US-00007 Example 5 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Methyl acrylate 25 2 Ethyl acrylate 20 Iso valeraldehyde 50 Dimethyl selenide 5

(24) TABLE-US-00008 Example 6 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Methyl acrylate 30 Ethyl acrylate 20 Iso valeraldehyde 40 2 Dimethyl selenide 10

(25) TABLE-US-00009 Example 7 Quantity Odor intensity Compound (ppmw) (Sales Diagram) Methyl acrylate 45 2 Ethyl acrylate 20 Iso valeraldehyde 30 Dimethyl selenide 5

(26) It will be readily apparent to one of ordinary skill in the relevant arts that suitable modifications and adaptations to the compositions, methods, and applications described herein can be made without departing from the scope of any embodiments or aspects thereof. The compositions and methods provided are exemplary and are not intended to limit the scope of any of the specified embodiments. All of the various embodiments, aspects, and options disclosed herein can be combined in any and all variations or iterations. The scope of the compositions, formulations, methods and processes described herein include all actual or potential combinations of embodiments, aspects, options, examples, and preferences herein described. All patents and publications cited herein are incorporated by reference for the specific teachings thereof.