WO2010071595A1

WO2010071595A1 - Denaturant-containing, ethanol-based liquid

Info

Publication number: WO2010071595A1
Application number: PCT/SE2009/051480
Authority: WO
Inventors: Roger Mattebo; Leif JÖNSSON; Björn Alriksson
Original assignee: Sekab Biofuels & Chemicals AB
Current assignee: Sekab Biofuels & Chemicals AB
Priority date: 2008-12-19
Filing date: 2009-12-21
Publication date: 2010-06-24
Anticipated expiration: 2011-06-19

Abstract

The present invention relates to a method for explicit denaturation of, and/or addition of denaturing capacity to other denaturants in, ethanol-based liquids, i.e. liquids that consist predominantly of ethanol, by addition of an organic chemical, characterized in that the added chemical has the formula (I) Wherein α is a single or double bond, β is a single or double bond, y is a single or double bond if both α and β are single bonds, v is a single bond if α or β is a double bond, and R₁ and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy.

Description

DENATURANT-CONTAINING, ETHANOL-BASED LIQUID

Technical field

A large number of ethanol-based liquids within various areas of use are available in the marketplace. One example of such a liquid is the one bearing the trade name

"T-Rod". It is used for example in alcohol stoves and for stain removal. The liquid usually consists of 95 % v/v ethanol. Other components are denaturants in the form of methyl ethyl ketone (MEK), acetone, ethyl acetate and Bitrex®. During recent years, the use of ethanol in vehicle fuels has grown greatly. E85 is an established vehicle fuel. The symbol represents a mixture of about 85 % v/v ethanol with about 15 % v/v gasoline. A number of other components are present in the mixture in a low concentration, including denaturants. In Sweden, the liquid described above is used as a vehicle fuel during the six months of summer. During the six months of winter, the admixture of gasoline is increased, such that the gasoline portion may comprise 25 % v/v. In diesel engine fuels, the proportion of denatured ethanol can be increased to more than 85 % v/v, up to 95 % v/v. This fuel mixture has been denoted ED95. The development of vehicle engines adapted to an increased use of bio-fuels (i.e. without admixture of any other fuel, such as for example gasoline) is one of the priority goals within the motor industry today, and it will likely not be long before such engines are in serial production.

Above, only a few examples of ethanol-based liquids are given, out of the liquids offered in the marketplace.

State of the art

There are requirements that ethanol-based liquids of the type described above are denatured. This is because people should refrain from consuming such fluids for intoxication purposes.

The following is a (translated) quote from LVFS 1995:2, "The Medical Products Agency's Regulations Regarding Use and Denaturation of Technical-grade Alcohol etc." (valid in Sweden): "Denaturation of technical-grade alcohol

4§ Technical-grade alcohol which is imported or sold under permit from the Medical Products Agency shall be denatured in one of the manners tabled in lists 1-3 below. The recited amounts of denatu rants refer to amounts per kg pure ethanol.

According to 3§ of the law (1961:181) concerning the sale of technical- grade alcohol etc, the Medical Products Agency may allow the import or sale of technical-grade alcohol without denaturation, if there are special reasons and no risk of misuse.

List 1

Denatured technical-grade alcohol intended to be used exclusively in the production of perfumes, eau de toilette, aftershave and other cosmetic products. 1:5 refers exclusively to production of oral hygiene products. 1:1 1O g diethyl phthalate, or

1:2 0,01 g Bitrex® + 1 g tert-butanol, or 1:3 60 g isopropanol + 1 g tert-butanol, or 1:4 6 g diethyl phthalate + 1 g tert-butanol. 1:5 15 g peppermint oil

List 2

Denatured technical-grade alcohol intended to be used in the production of merchandise which is not intended for human consumption, in processes for production, for scientific reasons or for medical reasons in hospitals or pharmacies.

2: 1 2O g methyl ethyl ketone, or 2:2 20 g methyl isobutyl ketone, or 2:3 20 g methyl tert-butyl ether, or 2:4 20 g toluene, or 2:5 30 g acetone, or 2:6 40 g butanol, or 2:7 50 g ethyl acetate, or 2:8 100 g iso-propanol. If the purpose is not suited to use of the general denaturants of lists 1 and 2, the Medical Products Agency may allow other denaturation of technical-grade alcohol.

List 3

Completely denatured technical-grade alcohol according to 4§ of the regulation (1994:1614) concerning alcohol tax, intended to be distributable without the levying of alcohol tax. Used for various technical and industrial purposes etc. 3:1 2O g methyl ethyl ketone + 3O g methyl iso-butyl ketone. " [underline added]

Used in Sweden as denaturants in ethanol fuels for combustion engines (otto engines) and compression engines (diesel engines) are for example iso-butanol and normal butanol, as well as methyl tert-butyl ether (MTBE) or ethyl tert-butyl ether (ETBE).

All denaturants must, according to the Swedish Medical Products Agency, fulfill the following to be authorized:

1) in the amount given, the chemical must not be so toxic/harmful, that a person, who nevertheless consumes the liquid, risks death or severe injury, but the rationale and aim of the addition of denaturant is that the denatured liquid should have such a repulsive smell and taste that no one wants to drink it, as well as causing vomiting on consumption,

2) they must be difficult to remove, i.e. they should preferably remain in the liquid regardless of how the liquid is treated with the aim of removing the denaturant.

The denaturants in current routine use have problems in fulfilling requirement 2 above. It has turned out that a person who knows how to purify the ethanol-based liquid may succeed in doing so. To improve the situation, the authorities have increasingly demanded double denaturing of such liquids, i.e. they frequently require that at least two denaturing chemicals are admixed into the liquid. Disclosure of the invention Technical problem

Many of the denaturants in current routine use do not completely fulfill the requirement that they be difficult to remove from ethanol-based liquids, i.e. liquids wherein the predominant species in terms of amounts is ethanol. There is thus a need for denaturants that have such a beneficial effect, and, above all, that improve the effect of double denaturation.

The solution This need is met and the problem solved by a method for explicit denaturation of, and/or addition of denaturing capacity to other denaturants in, ethanol-based liquids, i.e. liquids that consist predominantly of ethanol, by addition of an organic chemical, characterized in that the added chemical has the formula I

y

I wherein

(i) α is a single or double bond, β is a single or double bond, y is a single or double bond if both α and β are single bonds, Y is a single bond if α or β is a double bond, and Ri and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy. (ii) According to one embodiment of (i), y is a single bond, (iii) According to one embodiment of (i) or (ii), α and β are both single bonds or both double bonds. (iv) According to one embodiment of any one of (i)-(iii), Ri and R₂ are not both hydrogen, (v) According to one embodiment of any one of (i)-(iv), Ri is different from

R₂.

(vi) According to one embodiment of any one of (i)-(v), α and β are both single bonds. (vii) According to one embodiment of any one of (i)-(vi), R₂ is hydrogen while Ri is selected from the group consisting of methyl, ethyl, methoxy and ethoxy.

(viii) According to one embodiment of any one of (i)-(vii), the chemical is not dimethyl-tetrahydrofuran.

Thus, the above embodiments may be combined in any desired fashion. For example, the chemical may be

Rn n .H

oΛ /P

wherein α and β are both single bonds or both double bonds and Ri is selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy or from the group consisting of methyl, ethyl, methoxy and ethoxy. According to a preferred embodiment, the chemical is selected from the group consisting of 2-methyltetrahydrofuran (CAS 96-47-9), 2-ethylfuran (CAS 3208-16-0), 2-methoxyfuran (CAS 25414-22-6), 2- ethoxytetrahydrofuran (CAS 13436-46-9) and tetrahydrofuran (CAS 109-99-

9).

According to a more preferred embodiment, the chemical is 2- methyltetrahydrofuran (CAS 96-47-9). The meaning of the term "predominantly" is described below.

By denaturant is meant a chemical which, if present in an ethanol- based liquid in a sufficient amount, has such a repulsive smell that it discourages consumption and when consumed may cause vomiting, yet is not so toxic/harmful that a person, who nevertheless consumes such an ethanol-based liquid comprising the denaturant, risks death or serious injury. Furthermore, it is preferable that a denaturant is difficult to separate from ethanol.

"Explicit denaturation" refers to inherent denaturing capacity, i.e. the capacity to achieve a denaturing effect in an ethanol-based liquid without admixture of other denaturants. "Other denaturants" refer to commercially available chemicals that have been used as denaturants, for example those that have been approved as denaturants according to national regulations. Examples of other denaturants are methanol, n-propanol, /so-propanol, isobutanol, sec-butanol, n-butanol, tert-butanol, and those described above in "List 2". The other denaturant may also be MTBE or ETBE. Preferably, it is n-propanol, /so- propanol, isobutanol, sec-butanol, π-butanol or terf-butanol, more preferably isobutanol.

It has been shown that the denaturing effect of the chemicals listed above increases with an increasing proportion of ethanol in an ethanol/gasoline mixture, and the same is likely to be true when the ethanol is in admixture with another chemical (or other chemicals) than gasoline. Already at an ethanol content of 75 % v/v, there is an effect, and at an ethanol content of 80 % v/v the effect is pronounced, and at an ethanol content of 85 % v/v, the effect is substantial. The above phenomenon may also be expressed as follows: increasing the ethanol content in an ethanol/gasoline mixture leads to an increase in the denaturing effect. The trend with regard to for example vehicle fuels is to increase the ethanol content at the expense of the gasoline content. Although the trend is towards an increased ethanol content in said liquids, not only in Sweden but in large parts of the world, there is at present countries where the ethanol proportion is lower than for example 75 % v/v, and the inventive denaturant chemicals have a beneficial effect in these cases too.

According to one embodiment, the amount of chemical to mix into the liquid is at least 0.5 % w/w, preferably at least 1 % w/w. The amount may be adjusted on a case-by-case basis, i.e. for each ethanol-based liquid and each chemical. According to an alternative, or complementary, embodiment, the amount is at most 10 % w/w, such as at most 5 % w/w. The percentages given here refer to percent of the liquid after addition according to the inventive method.

The manner of adding the chemical makes no difference, i.e. whether it is added in one portion of the mixture, for example the ethanol portion, or in the final mixture. The present invention also encompasses a product in the form of an ethanol-based liquid in which the ethanol part is predominant, comprising denaturant(s) including a specific denaturant in an amount of less than 15 % v/v, characterized in that the specific denaturant is a chemical according to formula I, wherein α is a single or double bond, β is a single or double bond, Y is a single or double bond if both α and β are single bonds, Y is a single bond if α or β is a double bond, and Ri and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy. Different embodiments of chemicals according to formula I are described above. These can be combined in any desired manner.

According to a preferred embodiment, the specific denaturant is selected from the group consisting of 2-methyltetrahydrofuran (CAS 96-47-9), 2-ethylfuran (CAS 3208-16-0), 2-methoxyfuran (CAS 25414-22-6), 2- ethoxytetrahydrofuran (CAS 13436-46-9) and tetrahydrofuran (CAS 109-99- 9).

According to a more preferred embodiment, the specific denaturant is 2-methyltetrahydrofuran (CAS 96-47-9).

The ethanol portion being predominant means that it is larger by volume than any other component of the ethanol-based liquid. The ethanol portion is for example greater than the portion of water, gasoline or any additive.

The liquid suitably comprises ethanol in an amount of at least 50 % v/v, and it is preferred that the ethanol portion is at least 75 % v/v, such as at least 80 % v/v. With regard to the denaturing effect, ethanol in an amount of at least 85 % v/v is optimal. According to one embodiment, the concentration of the specific denaturant in the mixture, i.e. in the ethanol-based liquid, is at least 0,5 % w/w, preferably at least 1 % w/w. According to alternative or supplementary embodiments, the concentration of the specific denaturant is at most 10 % w/w, such as at most 5 % w/w. It may be considered contradictory that the different components of the liquid are characterized, in this document, both in terms of % v/v and % w/w, but, according to well-established conventions within the field, the unit % v/v (volume percent) is used for ethanol as well as for hydrocarbons, primarily gasoline, whereas the unit % w/w (weight percent) is used for chemicals that are added in small or very small amounts. These units may be converted into each other using the density of the chemical.

According to a preferred embodiment of the invention, the ethanol- based liquid consists of a vehicle fuel, wherein the supplementary fuel portion is a liquid hydrocarbon-based fuel, except when the fuel consist exclusively of ethanol. By "except when the fuel consist exclusively of ethanol" is meant those cases where ethanol is the only fuel component. In such cases, however, additives that have a main purpose other than to serve as fuel may be present in the ethanol-based liquid. Examples of such additives are denaturants, corrosion inhibitors and lubricants.

"Liquid hydrocarbon-based fuel" refers to a liquid fuel consisting primarily of hydrocarbons, i.e. chemical compounds solely comprising carbon and hydrogen. The liquid hydrocarbon-based fuel may for example be obtainable from petroleum. One example of a liquid, hydrocarbon-based fuel is gasoline, which may comprise octane boosting or other additives.

The invention also relates to the use of a chemical according to formula I, wherein α is a single or double bond, β is a single or double bond, y is a single or double bond if both α and β are single bonds, v is a single bond if α or β is a double bond, and Ri and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy, for denaturing of an ethanol-based liquid, in which liquid the ethanol portion is predominant. Different embodiments of chemicals according to formula I are described above. These can be combined in any desired manner. According to a preferred embodiment, the chemical is selected from the group consisting of 2-methyltetrahydrofuran (CAS 96-47-9), 2-ethylfuran (CAS 3208-16-0), 2-methoxyfuran (CAS 25414-22-6), 2- ethoxytetrahydrofuran (CAS 13436-46-9) and tetrahydrofuran (CAS 109-99-

9). According to a more preferred embodiment, the chemical is 2- methyltetrahydrofuran (CAS 96-47-9). In summary, the ethanol-based liquid according to the method, product or use above may comprise ethanol in an amount of at least 50 % v/v, for example at least 75, 80, 85 or 90 % v/v.

Below follows a more detailed description of the properties of the five chemicals recited above.

2-Methyltetrahydrofuran (CAS 96-47-9) Molecular formula = C₅H₁₀O Molecular weight = 86.13 Flash point = -12 ⁰C

Boiling point = 78 ⁰C

1 % solution in ethanol smells like solvent.

2-Ethylfuran (CAS 3208-16-0) Molecular formula = C₆H₈O

Molecular weight = 96.12

Flash point = -2 ⁰C

Boiling point = 92-93 ⁰C

1 % solution in ethanol smells like solvent.

2-Methoxyfuran (CAS 25414-22-6)

Molecular formula = C₅H₆O2

Molecular weight = 98.10

Flash point = 10 ⁰C Boiling point = 113-116 ⁰C

1 % solution in ethanol smells like solvent.

2-Ethoxytetrahydrofuran (CAS 13436-46-9) Molecular formula = CeHi₂O₂ Molecular weight = 116.16 Flash point = 16 ⁰C

Boiling point = 170-172 ⁰C

1 % solution in ethanol smells like solvent. Tetrahydrofuran (CAS 109-99-9) Molecular formula = C₄H₈O Molecular weight = 72.11 Flash point = -14 ⁰C

Boiling point = 66 ⁰C

1 % solution in ethanol smells like solvent.

It is quite possible to limit the addition of denaturant to the ethanol- based liquid to one of the chemicals according to the invention. It is also possible to add more than one of these chemicals. The addition of at least one of the chemicals according to the invention together with a previously known denaturant is preferred.

Advantages

As is evident from the examples to follow, the denaturants according to the invention possess a denaturing effect of their own. Furthermore, the agents may have an effect on other added denaturants such that they resist, to a surprisingly large extent, attempts at complete removal thereof from an ethanol-based liquid.

It is contemplated that the denaturants according to the invention are prepared from renewable starting materials, for example biomass, such as lignocellulosic material. Because ethanol is usually prepared from renewable sources and dominate the liquids in question in terms of relative amounts, denaturants according to the invention that are prepared for example from lignocellulosic materials contribute to a larger environmental value in the product. Best mode

The invention will now be described using a number of experiments carried out in a laboratory.

Example 1

The vehicle fuel E85 is regularly denatured by addition of 0,5 % w/w isobutanol (4,000 mg/l) and 2,5 % w/w MTBE, i.e. methyl tert-butyl ether (20,000 mg/l). This liquid was subjected to polar extraction and purification with activated carbon. The purified ethanol/water mixture contained no trace of MTBE, while a small amount of the added isobutanol remained, 54 mg/l to be precise. Thus, all the added MTBE and a large portion of the added isobutanol was transferred to the gasoline phase, which, as is evident from the above, may be removed from the mixture, i.e. from the ethanol-based liquid. This result is unsatisfactory in terms of denaturation.

The experiment was repeated, replacing the conventional denaturant MTBE by a denaturant according to the invention, namely MTHF, i.e. 2- methyltetrahydrofuran. All other conditions were as for the experiment described above. In this case, after the purification treatment, the ethanol/water mixture contained 800 mg/l MTHF and 2,100 mg/l isobutanol. As is readily apparent, a large portion of the added MTHF remains in the ethanol/water mixture after the described purification treatment. MTHF has, in itself, a denaturing effect. Furthermore, this addition of the chemical according to the invention contributes to the fact that the isobutanol is retained in such a substantial amount as 2,100 mg/l, to be compared with the 54 mg/l of the comparative experiment. At present, we have no scientific explanation for this exceedingly surprising result. The fact that such large portions of the added denaturing chemicals remain in the purified liquid has the effect that the liquid still smells of solvent. Example 2

Three more purification experiments were performed on ethanol-based liquids in the form of vehicle fuels.

"E85 summer", which means that the ethanol content was 86 % v/v, was denatured in part with 1 % w/w MTHF plus 1.5 % w/w isobutanol (= a), in part with 2.5 % w/w MTHF plus 0.5 % w/w isobutanol (= b).

"E85 winter", which means that the ethanol content was 78 % v/v, was denatured with 2.5 % w/w MTHF plus 0.5 % w/w isobutanol.

The achieved results are apparent from table 1 below.

Table 1

With regard to E85 winter, in which the volume content of ethanol is 78 % and the volume content of gasoline is 22 %, MTHF is retained to a small extent, viz. 10 mg/l, whereas the amount of isobutanol is ten times as high, i.e. 100 mg/l.

An increase of the ethanol content to 86 % v/v, i.e. E85 summer, leads to a substantially improved denaturing effect.

The water content given in the table refers to the water content in the mixture after addition of water to the ethanol-based liquid for purification purposes.

Example 3

The series of experiments was concluded with a purification experiment on yet another ethanol-based liquid in the form of a vehicle fuel. "E85 winter, extra" consisted of 76.1 % v/v ethanol, 19.7 % v/v gasoline, 3.85 % w/w MTHF and 0.39 % w/w isobutanol. The biggest difference in comparison with the winter mixture described above is that the amount of added MTHF has been substantially increased. The achieved results are given in table 2 below.

Table 2

Again, a certain denaturing effect is achieved, as a result of both chemicals being retained in small amounts after the purification treatment. However, it is clear that a large increase in added MTHF only leads to a minor increase in the amount of retained MTHF.

Taken together, the experiments show that the effect of the denaturing chemicals according to the invention is optimized along with an increase in the relative predominance in terms of the amount of ethanol present in ethanol-based liquids.

Claims

1. A method for explicit denaturation of, and/or addition of denaturing capacity to other denaturants in, ethanol-based liquids, i.e. liquids that consist predominantly of ethanol, by addition of an organic chemical, characterized in that the added chemical has the formula I

^Rκ .o. βϊ

a \ /β y

I wherein α is a single or double bond, β is a single or double bond,

Y is a single or double bond if both α and β are single bonds,

Y is a single bond if α or β is a double bond, and

Ri and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy.

2. The method according to claim 1 , characterized in that the chemical is selected from the group consisting of 2-methyltetrahydrofuran (CAS 96-47- 9), 2-ethylfuran (CAS 3208-16-0), 2-methoxyfuran (CAS 25414-22-6), 2- ethoxytetrahydrofuran (CAS 13436-16-9) and tetrahydrofuran (CAS 109-99- 9).

3. The method according to claim 2, characterized in that only one of the chemicals of the group is added.

4. The method according to claim 2, characterized in that at least two of the chemicals of the group are added.

5. The method according to any one of claims 1-4, characterized in that the liquid to which the organic chemical is added consists of ethanol in an amount of at least 75 % v/v.

6. The method according to any one of claims 1-5, characterized in that the chemical is added in an amount of at least 0.5 % w/w, preferably at least 1 % w/w and at most 5 % w/w.

7. The method according to any one of claims 1-6, characterized in that the chemical is added together with another denaturant.

8. An ethanol-based liquid in which the ethanol part is predominant, comprising denaturant(s) including a specific denaturant in an amount of less than 15 % v/v, characterized in that the specific denaturant is a chemical according to formula I, wherein α is a single or double bond, β is a single or double bond,

Y is a single or double bond if both α and β are single bonds,

Y is a single bond if α or β is a double bond, and Ri and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy.

9. The ethanol-based liquid according to claim 8, characterized in that the ethanol content is at least 75 % v/v.

10. The ethanol-based liquid according to claim 8, characterized in that the ethanol content is at least 80 % v/v.

11. The ethanol-based liquid according to claim 8, characterized in that the ethanol content is at least 85 % v/v.

12. The ethanol-based liquid according to any one of claims 8-11 , characterized in that the amount of the specific denaturant is at least 0.5 % w/w and at most 5 % w/w.

13. The ethanol-based liquid according to any one of claims 8-12, characterized in that the liquid is a vehicle fuel wherein the supplementary fuel portion is a liquid hydrocarbon-based fuel, except when the fuel consists exclusively of ethanol.

14. The ethanol-based liquid according to any one of claims 8-13, characterized in that the liquid comprises one or more other denaturants.

15. A use of a chemical according to formula I, wherein α is a single or double bond, β is a single or double bond,

Y is a single or double bond if both α and β are single bonds,

Y is a single bond if α or β is a double bond, and

Ri and R₂ are independently selected from the group consisting of hydrogen, methyl, ethyl, methoxy and ethoxy, for the denaturation of an ethanol-based liquid, in which the ethanol part is predominant.