WO2023102759A1

WO2023102759A1 - A composition comprising 2-amylenyl-anthraquinones, preparation method and its use thereof

Info

Publication number: WO2023102759A1
Application number: PCT/CN2021/136258
Authority: WO
Inventors: Fan Jiang; Zhen YAN; Stephane Streiff; Frederic Gillin; Andrew WILLSON; Francois Dabeux
Original assignee: Solvay Sa; Solvay (China) Co., Ltd
Priority date: 2021-12-08
Filing date: 2021-12-08
Publication date: 2023-06-15

Abstract

The present invention relates to a composition comprising 2-amylenyl-anthraquinones and to its preparation method. The composition can be used for producing a composition comprising 2-amylanthraquinone isomers with specific molar ratio.

Description

A composition comprising 2-amylenyl-anthraquinones, preparation method and its use thereof

TECHNICAL FIELD

The present invention relates to a composition comprising 2-amylenyl-anthraquinones and to its preparation method.

BACKGROUND

The following discussion of the prior art is provided to place the invention in an appropriate technical context and enable the advantages of it to be more fully understood. It should be appreciated, however, that any discussion of the prior art throughout the specification should not be considered as an express or implied admission that such prior art is widely known or forms part of common general knowledge in the field.

Hydrogen peroxide is an important green basic chemical for industry. The use of alkyl-substituted anthraquinones for the production of hydrogen peroxide is well known. In this process, substituted anthraquinones and/or tetrahydro anthraquinones dissolved in a suitable organic solvent mixture, a so called working solution, are hydrogenated to form the corresponding hydroquinones. The hydroquinones are then oxidised back to quinones with oxygen (usually air) with simultaneous formation of hydrogen peroxide, which then can be extracted with water while the quinones are returned with the working solution to the hydrogenation step.

Currently, most companies use 2-ethylanthraquinone. Compared with 2-ethylanthraquinone, 2-amylanthraquinone (mostly 2-neopentylanthraquinone or 2-tert-amylanthraquinone) has obvious advantages, such as better solubility in the solvent system, which affects the subsequent reaction rate and therefore affects the production cost and yield of hydrogen peroxide.

Chinese Patent Application Publication No. 104436896 A discloses a method for producing 2-amylanthraquinone, comprising two steps: (1) reacting tert-amylbenzene with phthalic anhydride in the presence of a catalyst to generate an intermediate 2- (4-neopentylbenzoyl) benzoic acid; (2) carrying out cyclization reaction on the intermediate 2- (4-neopentylbenzoyl) benzoic acid in the presence of a catalyst to generate 2-amylanthraquinone. Disadvantageously, after step (1) , it is necessary to neutralize the reaction mixture in order to obtain the intermediate. In step (2) , it is easy to form tar-like impurities during the dehydration process and therefore affect the yield and purity of 2-amylanthraquinone.

Chinese Patent Application Publication No. 111825544 A teaches a method for preparing a 2-alkylanthraquinone, comprises the following steps: (1) contacting anthracene with an alkylation to prepare a 2-alkylanthracene; (2) separating the 2-alkylanthracene; (3) oxidizing the 2-alkylanthracene to prepare a 2-alkylanthraquinone. According to step (2) , in order to separate the anthracene and 2-alkylanthracene, it is necessary to heat the reaction product containing alkylanthracene obtained in step (1) to a molten state, and then cool and crystallize anthracene and a series of alkylanthracene products containing 2-alkylanthracene. The melting temperature is from 200-270℃ and preferably 210-250℃.

SUMMARY OF THE INVENTION

The Applicant perceived that a need still exists for a composition comprising 2-amylanthraquinone isomers with specific molar ratio.

The Applicant found that the composition comprising 2-amylanthraquinone isomers can be obtained by the selective hydrogenation of corresponding 2-amylenyl-anthraquinone precursors mixture.

In addition, the Applicant surprisingly found that the composition comprising 2-amylanthraquinone isomers with specific molar ratio has better solubility in the solvents used in the preparation of hydrogen peroxide. Thus, better performance can be expected when it acts as a reaction carrier.

Thus, in a first aspect, the present invention relates to a composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) ,

wherein:

- R ¹ is an amylenyl group having a linear C ₃ main chain connected with two C ₁ side chains, the carbon connected to anthraquinone ring is connected with one and only one C ₁ side chain,

- the molar ratio of the at least one first 2-amylenyl-anthraquinone having the general formula (I) to the second 2-amylenyl-anthraquinone having the general formula (II) is of at least 9: 1.

In a second aspect, the present invention provides a method for preparing a composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) , by reacting a salt having the general formula (III) with a C ₅ alkene in the presence of a catalyst and a solvent,

wherein:

- Z is the equivalent of an anion of an organic or inorganic acid having a pKa of less than 7,

In a third aspect, the present invention relates to a composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) , wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is of at least 9: 1.

In a fourth aspect, the present invention relates to use of the composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) with a molar ratio of at least 9: 1 in the preparation of hydrogen peroxide.

Other subjects and characteristics, aspects and advantages of the present invention will emerge even more clearly on reading the detailed description and the examples that follow.

DEFINITIONS

Throughout the description, including the claims, the term "comprising one" should be understood as being synonymous with the term "comprising at least one" , unless otherwise specified, and "between" should be understood as being inclusive of the limits.

As used herein, the term “amylenyl” is a hydrocarbon group formed when a hydrogen atom is removed from an amylene group.

As used herein, the terminology " (C _n-C _m) " in reference to an organic group, wherein n and m are both integers, indicates that the group may contain from n carbon atoms to m carbon atoms per group.

The articles “a” , “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

The term “and/or” includes the meanings “and” , “or” and also all the other possible combinations of the elements connected to this term.

It is specified that, in the continuation of the description, unless otherwise indicated, the values at the limits are included in the ranges of values which are given.

Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also all the individual numerical values or sub-ranges encompassed within that range as if each numerical value or sub-range is explicitly recited.

DETAILS OF THE INVENTION

The composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II)

Preferably, the molar ratio of the at least one first 2-amylenyl-anthraquinone having the general formula (I) to the second 2-amylenyl-anthraquinone having the formula (II) can be from 9: 1 to 36: 1.

In some embodiments, the molar ratio of the at least one first 2-amylenyl-anthraquinone having the general formula (I) to the second 2-amylenyl-anthraquinone having the formula (II) can be from 16: 1 to 18: 1.

As previously mentioned, R ¹ is an amylenyl group having a linear C ₃ main chain connected with two C ₁ side chains, the carbon connected to anthraquinone ring is connected with one and only one C ₁ side chain.

The first 2-amylenyl-anthraquinone can be a compound having the formula (I-1) , a compound having the formula (I-2) or a compound having the formula (I-3) .

In some embodiments, the at least one first 2-amylenyl-anthraquinone having the general formula (I) can be a mixture of the compound having the formula (I-1) , the compound having the formula (I-2) and the compound having the formula (I-3) .

The method for preparing the composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II)

The present invention also relates to a method for preparing a composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) , by reacting a salt having the general formula (III) with a C ₅ alkene in the presence of a catalyst and a solvent,

wherein:

- the molar ratio of the first 2-amylenyl-anthraquinone having the general formula (I) to the second 2-amylenyl-anthraquinone having the general formula (II) is of at least 9: 1.

The first 2-amylenyl-anthraquinone has the same meaning as defined above.

The C ₅ alkene is an alkene isomer of C ₅H ₁₀, such as 2-methyl-2-butene, 2-methyl-1-butene and 3-methyl-1-butene. Among these, 2-methyl-2-butene is most preferable.

Possible acid radicals Z are, for example, BF ₄ ^-, HSO ₄ ^-, PF ₆ ^-, SO ₄ ^2-, Cl ^-, CH ₃COO ^- and aryl-SO ₃ ^- in which the aryl radical may be substituted, for example naphthalenesulfonate or benzenesulfonate. Preferably, Z is BF ₄ ^- or HSO ₄ ^- and more preferably HSO ₄ ^-.

Possible catalyst can be homogeneous metal catalysts and preferably homogeneous palladium catalysts. Said homogeneous palladium catalyst can be selected from the group consisting of Pa (dba) ₂, Pd ₂ (dba) ₃, Pd (OAc) ₂, Pd (acac) ₂, Pd (allyl) Cl ₂, Pd (PPh ₃) ₄ and Pd (TFA) ₂. Among these, Pa (dba) ₂ is most preferable.

The catalyst can also be heterogeneous metal catalysts and preferably heterogeneous palladium catalysts. Said heterogeneous palladium catalyst can be selected from the group consisting of Pa/C, Pd/Al ₂O ₃ and Pd/BaSO ₄.

The molar ratio of the catalyst to the C ₅ alkene can be from 0.004: 1 to 0.200: 1.

The molar ratio of the salt having the general formula (III) to the C ₅ alkene can be from 0.06: 1 to 1.2: 1 and preferably 0.07: 1 to 1.1: 1.

The solvent is typically chosen based on its ability to dissolve the reactants. It may be selected from the group consisting of water, methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butanol, tert-amyl alcohol, isoamyl alcohol, DMF (N, N-Dimethylformalmide) , acetonitrile and mixtures thereof.

In some embodiments, the solvent is substantially free of water.

As used herein, the term "substantially free of water" when used with reference to the solvent means that the solvent comprises no more than 0.5 wt. %, preferably no more than 0.2 wt. %of water, based on the total weight of the solvent.

In some embodiments, the solvent is completely free of water.

As used herein, the term "completely free of water" when used with reference to the solvent means that the solvent comprises no water at all.

Preferably, the reaction can be carried out under room temperature.

Preferably, the reaction time can be from 15 to 30 hours and preferably 20 to 25 hours.

Advantageously, this method, by a one-pot reaction, provides a composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) with specific molar ratio. Such composition can be a mixture of precursors for the preparation of the following composition which comprises a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) .

The composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V)

The present invention also relates to a composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) , wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is of at least 9: 1.

Preferably, the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) can be from 9: 1 to 36: 1.

In some embodiments, the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) can be from 16: 1 to 18: 1.

The composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) can be prepared by hydrogenating a composition comprising at least one first 2- amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) above mentioned in the presence of a catalyst. The skilled person can use known methods, such as ACS Catal. 2019, 9, 8, 7596–7606 and US 2018/0361370 A1 to only hydrogenate the double bond in amylenyl group without further hydrogenating any one of the double bonds in aromatic ring. Advantegously, the preparation method obviates the prior art drawbacks discussed above.

It has been surprisingly found out that the composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) with specific molar ratio has better solubility in the solvents normally used in the preparation of hydrogen peroxide. Said solvents are especially alkylated aromatic hydrocarbons as mentioned in Catal Lett (2010) 139: 105–113, US 2890105 and US 2158525.

The present invention also concens to use of the composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) in the preparation of hydrogen peroxide, wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is of at least 9: 1.

The following examples are included to illustrate embodiments of the invention. Needless to say, the invention is not limited to describe examples.

EXPERIMENTAL PART

Raw Materials:

Synthesis of 9, 10-dioxo-9, 10-dihydroanthracene-2-diazonium bisulfate (AQ-N ₂ ⁺HSO ₄ ^-)

A 3-necked round bottom flask (flask 1) is equipped with a constant-pressure dropping funnel (funnel 1) , a thermometer, and an oil-sealed bubbler, purged under nitrogen atmosphere. At 0-5℃, to flask 1, 2-aminoanthraquinone (1.0 equiv., 1g) was loaded together with a stirring bar. Then 98%H ₂SO ₄ (17ml) was loaded into the funnel. Under stirring at 0-5℃, 98%H ₂SO ₄ was dropped into flask 1 slowly. The 2-aminoanthraquinone was dissolved in H ₂SO ₄ and provide a dark solution. At 0-5℃, to a flat-bottom flask (flask 2) equipped with another constant-pressure dropping funnel (funnel 2) , NaNO ₂ (3.0 equiv., 0.93 g) was loaded. After, 98%H ₂SO ₄ (8 ml) was loaded into funnel 2, and then dropped very slowly into flask 2. An orange gas generation was observed due to the release of NO ₂. After the disappear of NO ₂, a colorless transparent solution (HNO ₂ and H ₂SO ₄ solution) from flask 2 was loaded into funnel 1 equipped on the previous flask 1 containing 2-amino-anthraquinone and H ₂SO ₄ maintained at 0-5℃. Under a nitrogen atmosphere, with a gas releasing apparatus, the freshly generated HNO ₂ and H ₂SO ₄ solution was added drop wise into 2-aminoanthraquinone and H ₂SO ₄ solution. The internal temperature was always monitored using the thermometer, and kept below 5℃, by controlling the addition speed. The addition lasted for 20 minutes, and another 1 hour stirring at 0-5℃ was required. After a sufficient stirring, a dark brown slurry was obtained. The slurry was filtered and washed with 0-5℃ icy water for 3 times. Brown sticky solid was obtained and transported into another 2-necked round bottom flask (flask 3) equipped with a stirring bar.

Synthesis of 9, 10-dioxo-9, 10-dihydroanthracene-2-diazonium tetrafluoroborate (AQ-N ₂ ⁺BF ₄ ^-)

At 0-5℃, deionized water (17 mL) and NaBF ₄ (2.15 equiv., 1.06 g) were loaded into flask 3 consequently and the internal temperature of the reaction was monitored and controlled by a thermometer. After 2 hours stirring at 0-5℃, a brown slurry was obtained, filtered, and washed with icy water 10 ml*5 times, cold ethanol 4 ml*2 times, and finally cold dichloromethane 7ml*2 times. A brown solid was obtained and transferred into a round bottom flask (flask 4) . Under vacuum in flask 4 the solid was dried for 6 hours at room temperature. Then the dry pale brown solid was stored in this flask sealed with a stopper and parafilm.

To mention, during the operation of the synthesis of diazonium salt, appropriate PPEs are obligatory for diazonium related compounds and process. Thus, a full mask with filters, anti-cutting gloves, safety goggles, and lab coats are necessary and obligatory during the whole operation closed to diazonium.

Example 1

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Catalysts (4.5 mol%, e.g. Pd (dba) ₂0.0048 g and other catalysts) were weighted and then loaded into the reactor, followed by anhydrous ethanol (9 mL) , then 2-methyl-2-butene (4.5 equiv., 87 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0644 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum &nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, ifthe reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp= 0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated following the equations below:

m _mixture=m _{reactor+mixture}-m _reactor ⁰

Internal standard calibration equation:

(Area _product/Area _bp) =slope* (m _product/m _bp) +intercept

m _product= [ (Area _product/Area _bp) -intercept) *m _bp] /slope

Yield _product=m _product/m _mixture

Conversion _diazonium=1- [ (Area _diazonium/Area _bp) -intercept) *m _bp] /slope

The results are listed in Table 1.

Table 1

No.	Catalyst	Yield of I+II/%	Ratio of I/II
1	Pd (dba) ₂	57.8	17.0
2	Pd (PPh ₃) ₄	13.1	12.5
3	Pd (TFA) ₂	11.8	16.9
4	Pd (OAc) ₂	15.7	17.1
5	Pd (acac) ₂	12.2	12.7
6	Pd (allyl) Cl ₂	16.6	12.8

I: the at least one first 2-amylenyl-anthraquinone having the general formula (I)

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 2

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (4.5 mol%, 0.0048 g) were weighted and then loaded into the reactor, followed by solvents (9mL, e.g. anhydrous ethanol) , then 2-methyl-2-butene (4.5 equiv., 87 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0644 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp= 0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table 2.

Table 2

No.	Solvent	Yield of I+II/%	Ratio of I/II
1	MeOH	58.2	24.5
2	EtOH	57.8	17.0
3	n-PrOH	37.1	16.2
4	n-BuOH	27.1	15.6
5	i-PrOH	32.9	9.9
6	t-amyl alcohol	11.5	11.2

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 3

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (4.5 mol%, 0.0048 g) were weighted and then loaded into the reactor, followed by anhydrous ethanol (3-25 mL) , then 2-methyl-2-butene (4.5 equiv., 87 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0644 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp=0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table 3.

Table 3

No.	EtOH amount/mL	Yield of I+II/%	Ratio of I/II
1	3	47.4	17.0
2	6	57.9	16.8
3	9	57.8	17.0
5	18	56.1	18.1
6	25	49.5	15.7

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 4

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (4.5 mol%, 0.0048 g) were weighted and then loaded into the reactor, followed by anhydrous ethanol (9 mL) , then olefins, e.g. 2-methyl-2-butene (4.5 equiv., 87 uL) , 3-methyl-1-butene (4.5 equiv., 93 uL) or 2-methyl-1-butene (4.5 equiv., 89 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0644 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp= 0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table 4.

Table 4

No.	Olefin	Yield of I+II/%	Ratio of I/II
1	2-Methyl-2-butene	57.8	17.0
2	2-Methyl-1-butene	12.7	16.6
3	3-Methyl-1-butene	16.4	20.6

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 5

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (2-20 mol%, 0.0022-0.216 g) was weighted and then loaded into the reactor, followed by anhydrous ethanol (9 mL) , then 2-methyl-2-butene (1 equiv., 19.5 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0644 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp=0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table5.

Table 5

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 6

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (6 mol%, 0.0065 g) was weighted and then loaded into the reactor, followed by anhydrous ethanol (9 mL) , then 2-methyl-2-butene (1-15 equiv., 19.5-299 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0644 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp=0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table 6.

Table 6

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 7

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (6 mol%, 0.0128 g) was weighted and then loaded into the reactor, followed by anhydrous ethanol (18 mL) , then 2-methyl-2-butene (10 equiv., 398 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.1288 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp=0.1200 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table 7.

Table 7

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 8

A 40mL Schlenck type pressure tube charged with a suitable stirring bar was pre-dried in the oven at 80℃, and then heat over heating gun under vacuum for 5 min. After cooling down, the reactor was charged with nitrogen and weighed (m _reactor ⁰) . Pd (dba) ₂ (see data in the table) was weighted and then loaded into the reactor, followed by anhydrous ethanol (see data in the table) , then 2-methyl-2-butene (10 equiv., 199 uL) , finally AQ-N ₂BF ₄ (1 equiv., 0.0605 g with 94%purity) . To mention, after each addition, the reactor was sealed immediately under nitrogen flow; after the last addition, fast vacuum&nitrogen purges were done for 3 times. The reaction mixture was then stirred under nitrogen at room temperature with 2500 r/min stirring speed for 22 hours. The mixture looked pale brown solid in light purple solution, if the reaction was completed, the mixture turned much darker with much less solid remaining. The reactor was weighed first (m _{reactor+mixture}) , then loaded with biphenyl (m _bp=0.0600 g) as internal standard. After sufficient stirring, all biphenyl was well dissolved. 0.5 mL solution was sampled into a GC vial and diluted with acetonitrile&ethanol till 1.5 mL. The solution was analyzed by HPLC&GC respectively, and calibrated with internal standards.

Yields and conversion were calculated in the same way as Example 1. The results are listed in Table 8.

Table 8

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 9

A 30mL stainless steel autoclave equipped a suitable stirring bar was pre-dried in the oven at 80℃. After cooling down, acetonitrile (6 mL) , 2-methyl-2-butene (10 equiv., 199 uL) , Pd-based heterogeneous catalyst (20 mg) , and finally AQ-N ₂BF ₄ (1 equiv., 0.0605 g with 94%purity) were loaded into the autoclave under argon atmosphere (see data in the table) . The autoclave was then closed and stirred under argon at room temperature for 16 hours. After reaction, biphenyl (m _bp=0.0600 g) was added as an internal standard. After dilution and filtration, the solution was analyzed by GC.

Yields and conversions were calculated in the same way as Example 1. The results are listed in Table 9.

Table 9

II: the second 2-amylenyl-anthraquinone having the formula (II)

Example 10

Solubility of 2-amylanthraquinone having the formula (IV) : A 10 mL colorless flask with a magnetic stirrer is weighed firstly (10.7946g) , 2-amylanthraquinone having the formula (IV) is weighed with the flask and stirrer (11.0830g, 2-amylanthraquinone having the formula (IV) weight=11.0830-10.7946=0.2884g) , then anhydrous toluene is added into the flask slowly at room temperature under 300 round/min stirring. After each additions of toluene the solution is stirred until the solid does not continue dissolving, and more toluene is added. Repeat this steps till all the solids dissolve. The flask is weighed 11.2348g, thus the mass of toluene is 0.1518g. The solubility of 2-amylanthraquinone having the formula (IV) in toluene at 23℃ is 1.90g/g of toluene.

Solubility of product 2-amylanthraquinone having the formula (V) : A 10 mL colorless flask with a magnetic stirrer is weighed firstly (10.8463g) , 2-amylanthraquinone having the formula (V) is weighed with the flask and stirrer (11.3200g, 2-amylanthraquinone having the formula (V) weight=11.3200-10.8463=0.4737g) , then anhydrous toluene is added into the flask slowly at room temperature under 300 round/min stirring. After each additions of toluene the solution is stirred until the solid does not continue dissolving, and more toluene is added. Repeat this steps till all the solids dissolve. The flask is weighed 11.7361g, thus the mass of toluene is 0.4161g. The solubility of 2-amylanthraquinone having the formula (IV) in toluene at 23℃ is 1.14g/g of toluene.

Solubility of the mixture of 2-amylanthraquinone having the formula (IV) and 2-amylanthraquinone having the formula (V) : A 10 mL colorless flask with a magnetic stirrer is weighed firstly (10.8081g) , the mixture in 9: 1 ratio is weighed with the flask and stirrer (11.3159g, the mixture of 2-amylanthraquinone having the formula (IV) and 2-amylanthraquinone having the formula (V) weight=11.3159–10.8081=0.5078g) , then anhydrous toluene is added into the flask slowly at room temperature under 300 round/min stirring. After each additions of toluene the solution is stirred until the solid does not continue dissolving, and more toluene is added. Repeat this steps till all the solids dissolve. The flask is weighed 11.5532g, thus the mass of toluene is 0.2373g. The solubility of the mixture in 9: 1 ratio in toluene at 23℃ is 2.14g/g of toluene.

Claims

A composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) ,

wherein:

- R ¹ is an amylenyl group having a linear C ₃ main chain connected with two C ₁ side chains, the carbon connected to anthraquinone ring is connected with one and only one C ₁ side chain,

- the molar ratio of the first 2-amylenyl-anthraquinone having the general formula (I) to the second 2-amylenyl-anthraquinone having the general formula (II) is of at least 9: 1.
The composition according to claim 1, wherein the molar ratio of the at least one first 2-amylenyl-anthraquinone having the general formula (I) to the second 2-amylenyl-anthraquinone having the formula (II) is from 9: 1 to 36: 1.
A method for preparing a composition comprising at least one first 2-amylenyl-anthraquinone having the general formula (I) and a second 2-amylenyl-anthraquinone having the formula (II) , by reacting a salt having the general formula (III) with a C ₅ alkene in the presence of a catalyst and a solvent,

wherein:

- Z is the equivalent of an anion of an organic or inorganic acid having a pKa of less than 7,

- R ¹ is an amylenyl group having a linear C ₃ main chain connected with two C ₁ side chains, the carbon connected to anthraquinone ring is connected with one and only one C ₁ side chain,

- the molar ratio of the first 2-amylenyl-anthraquinone to the second 2-amylenyl-anthraquinone is of at least 9: 1.
The method according to Claim 3, wherein the molar ratio of the first 2-amylenyl-anthraquinone to the second 2-amylenyl-anthraquinone is from 9: 1 to 36: 1.
The method according to Claim 3 or 4, wherein the molar ratio of the salt having the general formula (III) to the C ₅ alkene is from 0.06: 1 to 1.2: 1 and preferably 0.07: 1 to 1.1: 1.
The method according to any one of Claims 3 to 5, wherein the C ₅ alkene is 2-methyl-2-butene.
The method according to any one of Claims 3 to 6, wherein Z is BF ₄ ^-, HSO ₄ ^- and more preferably HSO ₄ ^-.
The method according to any one of Claims 3 to 7, wherein the catalyst is selected from the group consisting of Pa (dba) ₂, Pd ₂ (dba) ₃, Pd (OAc) ₂, Pd (acac) ₂, Pd (allyl) Cl ₂, Pd (PPh ₃) ₄ and Pd (TFA) ₂ and preferably Pa (dba) ₂.
The method according to any one of Claims 3 to 7, wherein the catalyst is selected from the group consisting of Pa/C, Pd/Al ₂O ₃ and Pd/BaSO ₄.
Use of the composition according to Claim 1 or 2 in the preparation of a composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) , wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is of at least 9: 1.
The use according to Claim 10, wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is from 9: 1 to 36: 1.
A composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) , wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is of at least 9: 1.
The composition according to Claim 12, wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is from 9: 1 to 36: 1.
Use of the composition comprising a first 2-amylanthraquinone having the formula (IV) and a second 2-amylanthraquinone having the formula (V) in the preparation of hydrogen peroxide, wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is of at least 9: 1,
The use according to Claim 14, wherein the molar ratio of the first 2-amylanthraquinone having the formula (IV) to the second 2-amylanthraquinone having the formula (V) is from 9: 1 to 36: 1.