JPH032398B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to high energy fuels, and more particularly to high density and high calorific value liquid fuels used for jet propulsion in rocket or jet engines. It is.

(Technical Background and Problems of the Invention) High-energy liquid fuels are used in rockets and jet engines such as turbojet, ramjet, and pulse jet. In order to increase the thrust of these jet engines, fuel with greater combustion energy per unit weight, that is, liquid fuel with high density and high combustion heat is required. Liquid fuel for these jet engines is supplied to the combustion chamber via a pipe, but since the flying object carrying the jet engine flies at a high altitude and is used in conjunction with liquid oxygen, liquid fuel is supplied to the combustion chamber via a pipe. The fuel is exposed to extremely low temperatures. Therefore, another required performance of liquid fuel for jet engines is that it has a low pour point and a low pour point, and has an appropriate viscosity even at low temperatures. Furthermore, liquid fuel for jet engines is required to have no unsaturated bonds and to be stable for long-term storage.

Conventionally, liquid fuels for jet engines include exotetrahydrodicyclopentadiene (JP-10, Japanese Patent Publication No. 45-20977) obtained by isomerizing dicyclopentadiene hydrogenated product with an acid catalyst, and norbonadiene. Quantified and hydrogenated product (RJ-5, US Patent No. 3377398)
etc. are known. Although JP-10 has good low-temperature fluidity, it has the disadvantages of low density and low combustion heat per volume. On the other hand, RJ-5 has a large calorific value per volume, but has poor low-temperature fluidity and
The drawback is that RJ-5 is difficult to synthesize and expensive.

(Objective of the Invention) The present invention aims to provide a high-density, high-calorific-value liquid fuel that satisfies the above-mentioned conditions required for a liquid fuel for a jet engine and can be manufactured at low cost and easily industrially. This is the purpose.

That is, the present invention involves the Diels-Alder reaction of 5-ethylidenenorbornene-2 and cyclopentadiene or/and methylcyclopentadiene, which are easily available on an industrial scale, to produce 1: After synthesizing an adduct and separating it, the carbon-carbon double bond is hydrogenated to produce a hydrocarbon compound with no unsaturated bonds, which is used as a high-density, high-calorific liquid fuel for jet engines. It is something to do.

(Summary of the invention) 5-ethylidenenorbornene used in the present invention
The Diels-Alder reaction of 2 with cyclopentadiene or methylcyclopentadiene proceeds primarily in the following manner to yield a 1:1 adduct ().

Depending on the reaction conditions, a small amount of 1:1 adduct (), for example, 5 mol % or less, may be formed in some reactions as follows.

Under normal Diels-Alder reaction conditions, Equation (2)
The reaction of 5-ethylidenenorbornene-2 and cyclopentadiene or methylcyclopentadiene is very slow compared to formula (1).
The main component of the 1 adduct is a compound having the structure ().

The Diels-Alder reaction between 5-ethylidenenorbornene-2 and cyclopentadiene or methylcyclopentadiene is a thermal reaction that does not require a catalyst. Cyclopentadiene and/or methylcyclopentadiene, which are reaction raw materials, may be added to the reaction system as monomers, but dicyclopentadiene, methyldicyclopentadiene, and methylcyclopentadiene, which are thermally decomposed under the reaction conditions to produce cyclopentadiene or methylcyclopentadiene, Dimethyldicyclopentadiene may also be used as a raw material. 5-ethylidenenorbornene-2
The molar ratio of and cyclopentadiene or/and methylcyclopentadiene is 1:0.001 to 1:10,
Preferably, it is used in a ratio of 1:0.01 to 2. The reaction temperature is 50 to 250°C, preferably 80 to 200°C when cyclopentadiene or methylcyclopentadiene is used as a raw material, and 100 to 250°C when dicyclopentadiene, methyldicyclopentadiene or dimethyldicyclopentadiene is used as a raw material component. ℃, preferably 120-200℃
It is. The reaction time varies depending on the reaction temperature, but is 10 minutes to 20 hours, preferably 30 minutes to 5 hours. During this Diels-Alder reaction, it is preferable to add a polymerization inhibitor such as hydroquinone, tert-butylcatechol, p-phenylenediamine, etc. to suppress the formation of a polymer. This reaction may also be carried out in a solvent that does not inhibit the reaction, such as a lower alcohol such as methanol or ethanol, or a hydrocarbon such as toluene or cyclohexane. In carrying out this Diels-Alder reaction, any of a batch, semi-batch or continuous reaction mode can be employed.

In the Diels-Alder reaction of 5-ethylidenenorbornene-2 and cyclopentadiene or methylcyclopentadiene, the above-mentioned 1:1 adduct [mainly ()] is produced, but a trimer of cyclopentadiene or methylcyclopentadiene is produced as a side reaction product. , a tetramer or a pentamer, and a multimer, in which cyclopentadiene or methylcyclopentadiene is further added to a 1:1 adduct (mainly ()), is also produced as a by-product.

These hydrides, which are by-products, have high melting points and poor low-temperature fluidity, so if they are mixed into liquid fuel oil for jet engines, they cause a decrease in performance, and in some cases, the fuel oil becomes unusable. Therefore, in order to synthesize a liquid fuel with high density, high calorific value, and good low-temperature fluidity in the present invention, a 1:1 adduct is distilled from the Diels-Alder reaction product obtained under the above reaction conditions. It is necessary to separate and purify it by means of

The 1:1 adduct of 5-ethylidenenorbornene-2 and cyclopentadiene or methylcyclopentadiene synthesized, separated and purified by the above procedure lacks chemical stability because it has two carbon-carbon double bonds, and cannot be used for a long period of time. Because stable storage is not possible,
In order to use it as a liquid fuel for jet engines, it is necessary to convert it into saturated hydrocarbons through a hydrogenation reaction. The hydrogenation reaction of this 1:1 adduct can be carried out under the same conditions as the hydrogenation reaction of ordinary unsaturated hydrocarbon compounds. In other words, the hydrogenation reaction uses noble metal catalysts such as platinum, palladium, rhodium, and ruthenium, and hydrogenation reaction catalysts such as Raney nickel.
At a temperature of 20~225℃, hydrogen pressure 1~~200Kg/ ^cm2
It can be easily carried out at a pressure of Further, although this hydrogenation reaction can be carried out without a solvent, it can also be carried out in a solvent such as a hydrocarbon, alcohol, ester, or ether. After the hydrogenation reaction of the 1:1 adduct is completed, the mixture of the solvent, unreacted materials, decomposition products produced in trace amounts in some cases, and catalyst residue is distilled, filtered, etc. to 1:1.
1 The hydride (tetrahydride) of the adduct is separated.

(Effect of the invention) The hydride of the 1:1 adduct of 5-ethylidenenorbornene-2 and cyclopentadiene or/and methylcyclopentadiene synthesized in this way has a high density with a specific gravity of 0.984 (15°C/4°C). It is a high calorific value liquid fuel for jet engines with a net calorific value of 10,000 cal/g or more, its melting point is -50°C or less, and it has excellent flow characteristics at low temperatures. Moreover, the fuel of the present invention is synthesized using industrially easily available 5-ethylidenenorbornene-2 and cyclopentadiene or/and methylcyclopentadiene as raw materials using the Diels-Alder reaction that does not require a catalyst. It also has the advantage that it can be synthesized at a lower cost than other liquid fuels for jet engines. The liquid fuel of the present invention has the advantage that it is chemically stable, has good long-term storage stability, and is not corrosive to metals.

5-ethylidenenorbornene-2 according to the invention
The hydride of the 1:1 adduct of cyclopentadiene and/or methylcyclopentadiene can be used alone as a fuel for jet engines, but
It can also be used in combination with known liquid fuels. Known fuels that can be mixed with the liquid fuel of the present invention include exotetrahydrodicyclopentadiene and norbornadiene, known as RJ-5.
trimeric hydrides of cyclopentadiene and methylcyclopentadiene (JP-A-57-59820), di- or tricyclohexyl alkanes (British Patent No. 977322), mono- or dicyclohexyl-dicyclic alkanes ( British Patent No. 977323), naphthenic hydrocarbons and isoparaffinic hydrocarbons (JP 57-139186)
Publication No.) etc.

(Examples) The present invention will be explained below in detail with reference to Examples, but the present invention is not limited to these Examples unless it departs from the gist of the present invention.

Example 1 362 of 5-ethylidenenorbornene-2 was placed in a stainless steel autoclave with a capacity of 2 and purged with nitrogen.
Add g and 225 g of dicyclopentadiene and heat at 157℃.
Stirred for 31 hours. After the reaction was completed, the reaction solution was distilled under reduced pressure, and 88g of unreacted 5-ethylidenenorbornene-2 was recovered, with a boiling point of 86℃/1.
407 g of mmHg fraction was obtained. When this fraction was analyzed using gas chromatography, the purity was found to be
It was 99.4%, and the molecular weight was 186 when measured using a mass spectrometer. Further, in IR analysis of this fraction, characteristic absorptions of olefin were observed at 3020 cm ^-1 and 1670 cm ^-1 . In ¹ H-NMR analysis, the absorption attributed to hydrogen bonded to a carbon-carbon double bond is δ5~
At 6.5 ppm, an absorption attributed to hydrogen not bonded to a carbon-carbon double bond was observed at δ1 to 3.5 ppm, and the area ratio of these peaks was 3:15.
These results revealed that this product was a 1:1 adduct of 5-ethylidenenorbornene-2 and cyclopentadiene. Therefore, the reaction rate of 5-ethylidenenorbornene-2 in this Diels-Alder reaction was 76%, and 5
The yield of the 1:1 adduct of -ethylidene norbornene and cyclopentadiene was 73%.

Hydrogenation of this 1:1 adduct was carried out as follows.
After putting 398 g of the 1:1 adduct synthesized by the above method and 3.5 g of palladium-carbon carrying 5% palladium into a stainless steel autoclave with a capacity of 2,
The mixture was stirred at 30° C. while maintaining the hydrogen pressure at 8 Kg/cm ² .
When the addition of hydrogen was stopped after 20 hours of reaction time, it was found that no hydrogen was absorbed, so the reaction was terminated. After removing the reaction from the autoclave and removing the catalyst, vacuum distillation was performed to obtain a hydrogenated product (66
℃/0.3mmHg) was obtained.

This hydrogenated product has a precipitation point of -50℃ or lower and a specific gravity (15℃/
4°C) 0.984, and the net calorific value was 10,050 cal/g.

Example 2 After purging a stainless steel autoclave with an internal volume of 2 with nitrogen, 5-ethylidenenorbornene-
Prepare 2600g and 330g of cyclopentadiene,
The mixture was heated gradually with stirring, and the internal temperature was increased from 25°C to 120°C over 2 hours. Thereafter, the mixture was reacted at 120°C for 5 hours. After the reaction was completed, the reaction solution was first distilled at normal pressure to remove unreacted cyclopentadiene, and then distilled under reduced pressure, resulting in a boiling point of 86℃/
119 g of 1 mmHg fraction was obtained. Gas chromatography analysis of this fraction revealed a 1:1 adduct of 5-ethylidenenorbornene-2 and cyclopentadiene at 99.1%.
% was included.

Next, after purging the stainless steel autoclave in step 1 with nitrogen, 100 g of the above 1:1 adduct and 0.5 g of Raney nickel were added and stirred, and the reaction temperature was increased to 40°C.
Hydrogen was continuously added to the solution at a concentration of 10 Kg/cm ² while controlling the amount. After 10 hours of reaction time, we stopped adding hydrogen and observed the drop in pressure, and found that there was no consumption of hydrogen, so we took out the reaction solution, separated the catalyst under a nitrogen stream, and started the reaction. When the liquid was distilled under reduced pressure, 95 g of a complete hydride of the 1:1 adduct (boiling point 66℃/0.3mmHg) was obtained.
Obtained. The hydride of this 1:1 adduct has a precipitation point below -50℃, a specific gravity of 0.984 (15℃/4℃),
The net calorific value was 10,040 cal/g.

Example 3 After purging a stainless steel autoclave with a capacity of 2 with nitrogen, 5-ethylidenenorbornene-2 was
600g of dimethyldicyclopentadiene and 480g of dimethyldicyclopentadiene were added, and the mixture was reacted at 170°C for 10 hours. After the reaction was completed, the reaction solution was distilled under reduced pressure to yield 5-ethylidenenorbornene-2 and methylcyclopentadiene 1:
1 adduct (boiling point 87℃/0.7mmHg, purity 95.4%)
365g was obtained.

Next, 300 g of a 1:1 adduct of 5-ethylidenenorbornene-2 and methylcyclopentadiene and 3.5 g of palladium-carbon carrying 5% palladium were placed in a stainless steel autoclave with a capacity of 1, and while maintaining the hydrogen pressure at 10 Kg/cm ^{2 .} The reaction was carried out at 50°C for 15 hours. After the reaction was completed, the catalyst was separated and the reaction solution was distilled under reduced pressure to obtain 279 g of a hydride of a 1:1 adduct of 5-ethylidenenorbornene-2 and methylcyclopentadiene (boiling point 78°C/0.3mmHg, purity 95.6%). Ta.

The precipitation point of this hydride is below -50℃, the specific gravity is 0.975 (15℃/4℃), and the net calorific value is 10030cal/
It was hot at g.

Claims (1)

[Claims] 1 5-ethylidenenorbornene-2 and cyclopentadiene or/and methylcyclopentadiene are subjected to a Diels-Alder reaction, resulting in a 1:1 ratio of 5-ethylidenenorbornene-2 and cyclopentadiene or methylcyclopentadiene.
A high-density fuel whose main component is a hydrogenated dimer obtained by hydrogenating the carbon-carbon double bond of an adduct.