Patent Application
20080032913
In the light of the above-stated prior art, the primary object of the present invention was to provide alternative or improved odoriferous substance mixtures for masking mineral oil odor and/or for fragrancing mineral oil fractions, in particular middle distillates such as diesel or heating oil. The odoriferous substances should here satisfy as many as possible and preferably all of a series of requirements, in particular:
According to a first aspect, the stated object is achieved solved by a mineral oil, characterized in that the mineral oil comprises a proportion of 0.5 ppm to 1.2 wt. %, relative to the entire mineral oil, of one or more odoriferous substances which are selected from the group (A) consisting of
The odoriferous substances or odoriferous substance mixtures of group (A) to be used according to the invention are preferably formulated in an additive and added to a mineral oil fraction or mixture of two or more mineral oil fractions in order to form a mineral oil according to the invention. The odoriferous substances of group (A) have a masking action against unpleasant mineral oil odor and so ensure greater acceptance and finer quality of mineral oils containing these odoriferous substances. The odoriferous substances of group (A) have a masking action against unpleasant mineral oil odor, in particular against the malodor of diesel and heating oil. They are readily available, may also be used in concentrated form, are largely or completely colorless, readily soluble in mineral oils and further mineral oil additive constituents, very stable in the mineral oil(s) to be odor masked and/or fragranced, in particular no discoloration and/or separation and/or haze occurs, and they moreover cause no obvious troublesome reactions with mineral oils or further conventional mineral oil additive constituents.
Conventional commercial motor fuels or oils, such as for example diesel fuels or heating oils which according to the invention comprise one or more odoriferous substances of group (A), often contain conventional additives. A mineral oil according to the invention therefore preferably comprises, in a total concentration of 0.001 to 2 vol. %, relative to the total volume of the mineral oil, one or more further additive constituents selected from the group consisting of:
An additive contained in the mineral oil according to the invention, in particular heating oil, diesel or gasoline, or usable for producing a mineral oil according to the invention preferably comprises, in addition to one or more odoriferous substances of group (A), at least one, preferably 2, 3, 4, 5, 6, 7 or all of the following constituents: flow promoters (WASA), lubricity improvers, antioxidants, ignition accelerators, antismoke agents, metal deactivators (chelating agents), stabilizers, detergents.
For producing an additive according to the invention or a mineral oil according to the invention, it may be of assistance for reasons of simpler apportioning or handling to add the odoriferous substance or odoriferous substances of group (A) to the additive or the mineral oil in the form of a mixture with one or more solvents or diluents. The solvent(s) or diluent(s) must here be compatible with the odoriferous substance(s) of group (A) and with the additives or the mineral oil fractions processed to yield the mineral oil according to the invention. Preferred solvents or diluents are here substances from one of the following groups L1 and L2 or a mixture of substances from both of groups L1 and L2 consisting of:
Solvents of group L2 are commercially obtainable, for example under the name Shellsol D60 or Shellsol D100 (defined mixtures of n- and iso-paraffins in the range from 9 to 14 C atoms) or Shellsol T (mixture of iso-paraffins).
One particular requirement when masking mineral oil odor is a low rate of addition of the odoriferous substance or the odoriferous substance mixture to the particular mineral oil. The concentration of odoriferous substances of group (A) preferably amounts in total to 1 to 1000 ppm, preferably 10 to 500 ppm and particularly preferably 30-300 ppm in heating oil, diesel and gasoline and 0.01-2 wt. %, preferably 0.1-2 wt. % and particularly preferably 0.2-2 wt. % in lubricant oils.
For the purposes of the present invention, advantageous mineral oils and additives are those with a number of at most 100 odoriferous substances which furthermore preferably comprise or consist of at most 80 odoriferous substances of group (A) to be used according to the invention. Preferred mineral oils and additives comprise at most 60 odoriferous substances, which furthermore preferably comprise or consist of at most 50 odoriferous substances of group (A) to be used according to the invention.
Particularly preferred mineral oils and additives comprise at most 30 odoriferous substances, which furthermore preferably comprise or consist of at most 3 to 30 odoriferous substances of group (A) to be used according to the invention.
The investigations carried out for the purposes of the present invention demonstrated that heating oil and lubricant oil is masked by a plurality of substances which differ greatly from this material. This was not to be expected in the light of U.S. Pat. No. 5,538,719, since, on the basis of the teaching therein, structurally similar compounds apparently effect mutual odor masking by means of cross-adaptation.
It has, however, now been found that, from among odoriferous substances of group (A), the odoriferous substances of the following group (B) are particularly suitable for reducing, masking or suppressing the stench of a mineral oil:
These odoriferous substances of group (B), which are a subset of group (A), have, as shown further below, the strongest action in reducing, masking or suppressing mineral oil malodor. They are therefore preferably used mineral oils in according to the invention, in particular in diesel and heating oil. A corresponding mineral oil particularly preferably contains two, three, four, five or more, preferably no more than 25, odoriferous substances of group (B).
A likewise preferred mineral oil according to the invention is one which contains, from among odoriferous substances of group (A), one or more odoriferous substances of the following group (C):
These odoriferous substances of group (C) also have, in addition to a good malodor reduction value (see below for further details), a strong and pleasant intrinsic odor which can contribute to improving the acceptance of a mineral oil according to the invention. Accordingly, a corresponding mineral oil is preferred which contains two, three, four, five or more, preferably no more than 25, odoriferous substances of group (C).
Odoriferous substances of group (B) and (C), in particular in combination, exert a particularly good action in improving the odor of a mineral oil and in reducing, masking or suppressing the stench of a mineral oil. A mineral oil according to the invention therefore preferably contains at least one, preferably two, three, four, five or more and furthermore preferably up to 25 odoriferous substances of group (B) and at least one, preferably two, three, four, five or more and furthermore preferably up to 25 odoriferous substances of group (C).
A preferred mineral oil is furthermore one which, in addition to the one or more odoriferous substances of group (B) and/or (C), additionally contains one or more of the odoriferous substances of group (D) below:
These odoriferous substances likewise have a good malodor reduction value and are furthermore distinguished in that, in mineral oils, they harmoniously round off the odor brought about by the odoriferous substances of group (B) and/or (C). A mineral oil according to the invention therefore preferably contains
In additives according to the invention, the total mass of odoriferous substances of group (A) preferably accounts for a proportion of 0.5 to 80 wt. %, preferably 2 to 50 wt. %, preferably 3 to 30 wt. %, in each case relative to the total weight of the additive.
For technical reasons, it is often desired to use only a small number of odoriferous substances which are active against unpleasant mineral oil odor. It is therefore preferred for the number of odoriferous substances from group (A), in particular from group (B), (C) and/or (D), in a mineral oil or additive according to the invention to amount from 2 to 50, with a number of odoriferous substances to be used according to the invention of 3 to 30 being particularly preferred, in each case relative to the entire mixture of odoriferous substances of group (A) in the mineral oil or additive.
For perfumery and hedonistic reasons, it is often necessary additionally to use a, in the present case small, proportion of odoriferous substances which are less active against mineral oil odor. Further odoriferous substances may therefore additionally be present in the mineral oil or additive in addition to the odoriferous substances of group (A), in particular of groups (B), (C) and/or (D). However, as described above, the overall total number of odoriferous substances in a mineral oil according to the invention should amount to no more than 100.
The above described preferably low rate of addition of odoriferous substances in mineral oils according to the invention entails particularly active odoriferous substances and odoriferous substance mixtures, such that these should preferably be composed of a not excessively large number of particularly active odoriferous substances. The possibility of additive discoloration in particular presents a difficulty. Such discoloration may for example be triggered by an excessively high concentration of vanillin, ethylvanillin, maltol and/or ethylmaltol in the perfuming composition. Vanillin is active against an unpleasant mineral oil odor, but may lead to severe discoloration in the additive. Vanillin, ethylvanillin, maltol and/or ethylmaltol should therefore be present in only the smallest possible quantities or be entirely absent from an additive for masking, reducing or suppressing malodor.
A mineral oil or additive according to the invention preferably comprises at least one, two three or more, preferably at most ten, further odoriferous substances (which are thus not part of the odoriferous substances of group (A) to be used according to the invention) with a vapor pressure of greater than or equal to 0.1 Pa at 25° C., preferably with a vapor pressure of greater than or equal to 0.5 Pa at 25° C., particularly preferably with a vapor pressure of greater than or equal to 1 Pa at 25° C.
Examples of further odoriferous substances which may be a constituent of an additive according to the invention or a mineral oil according to the invention may be found, for example, in S. Arctander, Perfume and Flavor Chemicals, vol. I and II, Montclair, N.J., 1969, private publication or K. Bauer, D. Garbe and H. Surburg, Common Fragrance and Flavor Materials, 4th ed., Wiley-VCH, Weinheim 2001.
Since essential oils generally comprise a plurality (often far in excess of 100 compounds) of odoriferous substances, which in some cases make no (appreciable) contribution to malodor masking due their low content in the essential oil, the total proportion of essential oils in mineral oils and additives according to the invention is preferably at most 25 wt. %, preferably at most 15 wt. %, further preferably at most 7 wt. %, relative to the total quantity of odoriferous substances of group (A) in the mineral oil or additive. In a particularly preferred embodiment, additives and mineral oil fractions according to the invention contain no essential oils, especially since some essential oils may result in discoloration, separation and/or haze in additives and mineral oil fractions according to the invention.
An advantageous mineral oil or additive according to the invention is one which comprises a total proportion of less than 8 wt. % of vanillin, ethylvanillin, maltol and/or ethylmaltol, relative to the total mass of odoriferous substances of group (A). A preferred mineral oil or additive according to the invention is one which comprises a total proportion of less than 4 wt. %, particularly preferably of less than 1.5 wt. %, of vanillin, ethylvanillin, maltol and/or ethylmaltol, relative to the total mass of odoriferous substances of group (A). These limits apply in particular to heating oil and diesel.
A particularly advantageous mineral oil or additive according to the invention is one having a proportion of less than 8 wt. % of vanillin relative to the entire quantity of odoriferous substances of group (A). A preferred mineral oil and additive according to the invention is one which comprises a proportion of less than 4 wt. % and particularly preferably of less than 1.5 wt. % of vanillin relative to the total quantity of odoriferous substances of group (A) in the mineral oil or additive. These limits apply in particular to heating oil and diesel.
Thanks to the use of mixtures of the stated odoriferous substances of group (A) and in particular of groups (B) and (C), a product may be perfumed in such a manner that a weak fragrance is perceived, while the presence of the unpleasant odor of mineral oil fractions is simultaneously suppressed. Strong perfuming of elevated intensity is not necessary in order to achieve the desired effect.
Perfuming compositions and odoriferous substance compositions are occasionally used for masking an unpleasant mineral oil odor. The development of such odoriferous substance compositions and the verification of their effectiveness in masking mineral oil odor has in the past proceeded by trial and error. Conventionally, a sample of an odoriferous substance or odoriferous substance mixture which is to be investigated for its mineral oil odor masking ability (masking sample) is mixed with a sample of the mineral oil fraction (malodor standard) to be masked and the resultant odor impression is determined olfactorily by a panel of testers. Accordingly, development of an odoriferous substance or odoriferous substance mixture which masks a mineral oil odor is at present a complex procedure.
The present invention therefore also provides a test method for verifying masking of mineral oil odor by a test sample comprising one or more odoriferous substances, comprising the steps:
The intensity of a substance or substance mixture describes the intensity of the mixture perceived olfactorily by trained testers, irrespective of the quality of the odor as a stench or pleasant odor. The stronger a substance or substance mixture smells, the higher is the intensity value. Intensity is here rated on a scale from 1 to 9. A value of 1 means odorless, while 9 means very strong smelling. In turn, the malodor impression describes the intensity of the perceived stench. In the present case, the term malodor reduction value describes the difference in intensity, i.e. the difference in the stench (malodor) of the malodor standard mixture and the test mixture.
The test method is preferably carried out at 20° C. and 1013 mbar. It is likewise preferred for the concentration of heating oil in the malodor standard mixture and the test mixture to be equally high. This permits particularly good comparison of the mixtures.
The test sample according to the invention preferably comprises one or more odoriferous substances. In this manner, relatively complex odoriferous substance mixtures, such as for example combinations of odoriferous substances and essential oils, may also be verified for their suitability for masking mineral oil odor.
The test method according to the invention is preferably carried out using a defined quantity of a mineral oil fraction.
For carrying out the test method according to the invention, it is additionally preferred for the concentration of the malodor standard heating oil in the test and/or malodor standard mixture to amount to at least 0.1 μl/l, preferably 0.1 to 1 μl/l and particularly preferably 0.3 to 0.8 μl/l. At this concentration, the stench of the malodor standard is already readily perceptible, but without the tester's sense of smell being largely overwhelmed by the malodor standard. This concentration then also does not impair the tester's cognitive ability or wellbeing if many (10-30) test samples are assessed in quick succession. These concentrations may particularly readily be established by vaporizing 5 μl of the mineral oil Fraction to be investigated in 7 l of air.
The test method is particularly preferably carried out by the individual test samples being tested for suitability for covering up a mineral oil odor in containers of an identical size. The individual test samples are here in each case assessed by at least 8 (expert) testers by smelling in comparison with a sample comprising only the mineral oil fraction (malodor standard). This malodor standard without odoriferous substance is preassigned an intensity of 6. Odor intensities are rated on a scale from 1, which corresponds to “odorless”, to 9, which corresponds to “very strong”. The reduction value is calculated by deducting the intensity of the standard from the mean odor intensity of the malodor. The testers are selected on the basis of their ability to assess the strength of odors reproducibly. Before the test series, the testers are trained to recognize the mineral oil odor.
As an alternative to the test method which has just been described, the odoriferous substance or odoriferous substance mixture to be tested is incorporated into the mineral oil fraction in question in a concentration of 50 ppm.
20 μl of the mineral oil fraction in question (reference sample), on the one hand, and 20 μl of the mineral oil fraction in question containing 50 ppm of the odoriferous substance or odoriferous substance mixture to be investigated, on the other hand, are introduced (generally pipetted centrally onto the bottom of the jar or beaker) at room temperature (approx. 20° C.) into two separate jars or beakers (each of a volume 200 ml). After 1 minute, both jars or beakers are evaluated in direct comparison with regard to odor by six trained testers.
Odor is evaluated in both cases using the following evaluation scale from 1-6:
1=no difference relative to reference sample
2=slight difference relative to reference sample
3=discernible difference relative to reference sample
4=distinct difference relative to reference sample
5=distinct difference relative to reference sample, odoriferous substance (mixture) is discernible
6=distinct difference relative to reference sample, odoriferous substance (mixture) is distinctly discernible
In particularly preferred embodiments of the invention, the odoriferous substances or odoriferous substance mixtures to be used according to the invention and the test sample found according to the invention containing one or more odoriferous substances may be combined with perfume oils.
Accordingly, the invention also provides a method for producing a mineral oil odor masking additive comprising the steps:
a) selecting a test mixture as previously described according to the invention,
b) preparing the additive containing the odoriferous substance(s) of the selected test mixture in an adequate concentration for masking mineral oil.
The invention additionally provides a mineral oil odor masking additive produced using a production method according to the invention.
Odoriferous substances of group (A) to be used according to the invention or an odoriferous substance mixture to be used according to the invention comprising 2, 3, 4, 5, 6, 7, 8, 9, 10 or more odoriferous substances of group (A) exhibit a malodor reduction value of greater than or equal to 2.3.
Preferred odoriferous substances of group (A) to be used according to the invention or an odoriferous substance mixture to be used according to the invention comprising 2, 3, 4, 5, 6, 7, 8, 9, 10 or more odoriferous substances of group (A) are those which exhibit a malodor reduction value of greater than or equal to 3.0, more preferably a malodor reduction value of greater than or equal to 3.5.
A. The testers must be capable of distinguishing the odor of heating oil from an odorless solvent (dipropylene glycol=DPG).
To this end, several paperboard smell strips are dipped in heating oil. In addition, several smell strips are dipped in DPG. Only those testers who are capable of distinguishing the smell strips without error in a test sequence heating oil-heating oil-DPG and DPG-DPG-heating oil take part in the further testing.
B. Various concentrations of the heating oil are then introduced into a defined volume of air. The testers sort the samples by intensity, i.e. strength of odor. The testers must correctly recognize and evaluate the sequence of concentrations. Those testers who have passed both tests may participate in the raw material test described below.
The investigated odoriferous substances are individual odoriferous substances (in some cases, they may also comprise mixtures of (E) and (Z) isomers or also of stereoisomers). The odoriferous substances are evaluated by the selected testers in a defined gaseous sample with regard to intensity and residual strength of the diesel or heating oil odor.
Not all of the odoriferous substances are equally soluble in mineral oil fractions. Therefore, before sample preparation, 30 μl of odoriferous substance and 150 μl of the diesel or heating oil are in each case mixed. 6 μl of the oil phase are placed in an air-filled vessel of a capacity of 7 l. The samples are kept at room temperature (approx. 20° C.) for 15 h before evaluation. The individual samples are in each case evaluated by at least 8 testers by smelling in comparison with a sample solely comprising 5 μl of diesel or heating oil. The mean of the at least 8 values obtained for the particular raw material is then calculated.
Reference is made to the above-stated definitions and explanations with regard terminology and the evaluation scale.
As has been found, the solvents Solutol A (2-(2-ethoxyethoxy)ethanol) and dipropylene glycol (DPG) have no influence on the intensity of the stench or the total intensity. These solvents may thus be used in place of the remaining constituents of a perfuming composition which are not being tested here. The odoriferous substances of group (A) listed in Table 1 exhibited very similar results for diesel or heating oil.
3 mixtures (A-C) were produced using the following formulations:
Mixtures A-C were tested using the above-stated method in comparison with 4,4a,5,9b-tetrahydro-indeno[1,2-d]-1,3-dioxine, 1-methyl-4-(1-methylethenyl)-cyclohexene and 2-(2-ethoxyethoxy)ethanol. The mixtures have the desired action. It proved possible to replicate the values for the individual substances.
Mixtures A-C were also tested at a rate of addition of 50 ppm in heating oil using the above-stated method in comparison with 4,4a,5,9b-tetrahydro-indeno[1,2-d]-1,3-dioxine, 1-methyl-4-(1-methylethenyl)-cyclohexene and }2-(2-ethoxyethoxy)ethanol. To this end, the perfuming compositions were stirred into the heating oil at this rate of addition. 10 g portions of the heating oil perfumed in this manner were placed 30 ml screw-top jars. The samples were evaluated in comparison with unperfumed heating oil using the same scale as in the above-stated method. In this test too, which is closer to the real-life application of the products, the mixtures have the desired action. Since only a few samples were compared in this manner, neither the personal wellbeing nor the cognitive ability of the testers were impaired. Here too, it proved possible to obtain the effects of the individual substances.
This application claims the benefit under 35 U.S.C. §119(e) of provisional patent application Ser. No. 60/834,561, filed Aug. 1, 2006, the entire disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60834561 | Aug 2006 | US |
