WO2015059506A1

WO2015059506A1 - Process for the production of disobutylcarbinol by hydrogenation of diisobutylketone

Info

Publication number: WO2015059506A1
Application number: PCT/IB2013/002353
Authority: WO
Inventors: Richard Macret; Giovanni Rosso
Original assignee: Rhodia Poliamida E Especialidades Ltda
Priority date: 2013-10-21
Filing date: 2013-10-21
Publication date: 2015-04-30
Also published as: AR098120A1

Abstract

This invention relates to the production of diisobutylalcohol (DIBC), and more particularly it relates to a process for producing diisobutylalcohol (DIBC) by hydrogenating diisobutylketone (DIBK) in presence of metallic catalysts. The process of the invention uses fractionated addition of the metallic catalyst into the reactor while removing the converted diisobutylalcohol fraction before each subsequent addition of catalyst.

Description

PROCESS FOR THE PRODUCTION OF DIISOBUTYLCARBINOL BY HYDROGENATION OF DIISOBUTYLKETONE

Background of the invention - prior art

This invention relates to the production of diisobutylalcohol (DIBC), and more particularly it relates to a process for producing diisobutylalcohol (DIBC) by hydrogenating diisobutylketone (DIBK) in presence of metallic catalysts.

Diisobutylketone (DIBK) is obtained as a by-product when producing methylisobutylketone (MIBK).

Indeed, MIBK is a widely used solvent that is generally obtained from acetone according to the following steps:

Acetone Diacetone Alcohol Mesityl Oxide MIBK

However, the excess of acetone in the reaction medium leads to the side reaction of MIBK with acetone according to the following steps:

Where 2-HDMH= 2-hydroxy-2,6-dimethylheptan-4-one, and 2,6-DMH= 2,6-dimethylhept-2-en-4- one.

Moreover, mesityl oxide (OM) can also react with acetone and produce an isomer of DIBK (i- DIBK) according to the following steps:

O

Dehydration ⁰ | | Hydrogenation

^"H2°

Mesityl Oxide ^reaction 4,6-DMH i-DIBK

Where 6-HDMH- 6-hydroxy-4,6-dimethylhept-3-en-2-one, and 4,6-DMH= 4,6-dimethylhepta-3,5- dien-2-one.

In consequence, when producing MIBK, a significant stream containing a mixture of DIBK and i- DIBK is also produced. One mean to valorise DIBK (and i-DIBK) is its further transformation into its corresponding alcohol (DIBC and i-DIBC), used for example as:

• Solvent or cosolvent in the anthroquinone process to produce hydrogen peroxide,

• Solvent for paints, lacquers, shellac, printing inks, vinyl-chloride-acetate resins, urea- melamine resins, and alkyd resins;

• Extraction or refining solvent in a variety of processes;

• Flotation agent;

• Chemical intermediate for dyestuffs, perfume manufacture, fabric softeners, pesticides, pharmaceuticals, lubricants, oil additives;

• Rubber additive, plasticizer, and surface-active agent;

• Defoamer in adhesives

• Dispersing agent in coatings

• Coupling solvent for synthetic resins.

The known method to transform DIBK into DIBC is the hydrogenation with a metallic catalyst. According to this method, the DIBK and all the catalyst, generally Raney Nickel^® (RaNi^®), are put together in a reactor and then hydrogen is added under pressure.

However, by using such a process, the conversion of DIBK into DIBC decreases significantly along the process due the catalyst deactivation.

For DIBK and i-DIBK hydrogenation (production of DIBC and i-DIBC, respectively) using RaNi^® in classical conditions, there is a loss in selectivity for DIBK hydrogenation. The selectivity is not modified for i-DIBK hydrogenation.

This conversion loss is a problem for industrialization of the process, increasing the variability of product composition (relation between DIBC and i-DIBC, for example), increasing the catalyst specific consumption and consequently increasing the costs.

In addition, when using the stream of DIBK coming from MIBK production as explained above, isomers of DIBK are also transformed into corresponding alcohols (i-DIBC). Some applications require that the ratio of isomers not exceeding more than 30% of i-DIBC in the final DIBC.

Brief description of the invention

The present invention aims to provide an optimized process for the preparation of diisobutylalcohol (DIBC) through hydrogenation of a diisobutylketone (DIBK) containing stream in presence of hydrogen and a metallic catalyst.

Specifically, it has surprisingly been found that the fractionated addition of the metallic catalyst into the reactor while removing the converted diisobutylalcohol fraction before each subsequent addition of catalyst, allows maintaining an excellent conversion of DIBK all along the process. Thus, the present invention is a process for the production of diisobutylalcohol by hydrogenation of diisobutylketone in a reactor in presence of hydrogen and a metallic catalyst, wherein:

• the addition of the catalyst in the reactor is a fractionated addition,

• the total quantity of catalyst present in the reactor at the end of the fractionated addition is from 1 to 30% by weight relative to the weight of the diisobutylketone stream to hydrogenate,

• an initial quantity of catalyst is introduced into the reactor with the diisobutylketone stream to hydrogenate, and

• the converted diisobutylalcohol fraction is removed from the reactor before each subsequent addition of catalyst.

The process according to the invention is advantageously a discontinuous process. The reactor used in the above process is preferably a batch reactor.

Detailed description of the invention

Definitions

By "fractionated", it should be understood in the sense of the present invention, that the addition of the catalyst comprises at least 2 additions, considering the initial quantity of catalyst introduced as the first addition. Preferably the addition of the catalyst is performed until the relation between catalyst and stream achieve 10% by weight relative to the weight of the stream to hydrogenate. Advantageously, the addition of the catalyst comprises at least 3 additions, more preferably in at least 5 additions and still preferably in at least 10 additions.

Catalyst

The metallic catalyst according to the present invention can be chosen in the group consisting in a metal selected from rhodium, ruthenium, and, nickel, more specifically Raney Nickel^®.

In the preferred embodiment the catalyst is Raney Nickel^®. Indeed, this catalyst has the better balance price/efficiency when compared to other metallic catalysts. Other catalysts like Copper, Ruthenium, Platinum and Rhodium based catalysts can also be used.

Advantageously, the total quantity of catalyst present in the reactor at the end of the fractionated addition reaches from 1 to 15% by weight relative to the weight of the diisobutylketone stream to hydrogenate, preferably from 8 to 10% by weight. Indeed, above 30% by weight, there is no economic interest in view of the conversion increase. Again, below 1% by weight, the reaction time is too low to satisfy the industrial requirements in terms of productivity.

The initial quantity of catalyst in the reactor can advantageously correspond to 1 to 7% by weight relative to the weight of the diisobutylketone stream to hydrogenate, preferably to 2 to 6% by weight. With this preferred range, the reaction time is optimized, while keeping the effect on the selectivity.

After the initial addition of catalyst, the number of subsequent additions of catalyst to the reactor is preferably from 1 to 100 , preferably from 5 to 70 and in particular from 10 to 60. Each subsequent addition can add an equal or different quantity of catalyst. For example, in a preferred embodiment the initial addition is of 3% by weight of catalyst, and then there are 7 subsequent additions of each 1% by weight of catalyst. In this embodiment, the total quantity of catalyst present in the reactor at the end of the fractionated addition is 10% by weight. This sequence has the advantage to keep the reactional media with catalyst in constant activity.

Alternatively, we can use other sequences as described below:

- initial addition 8% by weight of catalyst, and then subsequent additions of 2% by weight of catalyst until 10% by weight of catalyst;

- initial addition 3% by weight of catalyst, and then subsequent additions of 1% by weight of catalyst until 10% by weight of catalyst.

According to a specific embodiment of the invention, once the total quantity of catalyst is reached, it is possible to remove at least a portion of the catalyst and to add the corresponding quantity of fresh catalyst.

Different devices can be used to undertake the fractioned addition of catalyst. For example it is possible to use manual or automatic systems.

Reaction conditions

In the process according to the invention, the reactor is preferably maintained at a temperature between 80 to 270°C, more preferably between 100 and 200°C, and advantageously between 120 and 170°C limits included. What does it mean? There is no upper limit for the temperature if your equipment allows you to heat more?

Concerning the pressure in the reactor, it is advantageously maintained between 0.5 and 3.0 MPa.

According to the process of the invention, the time between each addition of catalyst corresponds preferably to the time necessary to reach the conversion target of the diisobutylketones (DIBK and i-DIBK), for example >90%, preferably >98%. The final concentration is limited by the composition of the feed.

During the reaction step the conversion of the diisobutylketones (DIBK and i-DIBK) is measured by hydrogen consumption and/or by analysis of the reaction medium.

Composition of the starting material The process of the invention uses a stream of diisobutylketone. This stream to be hydrogenated advantageously comprises from 30 to 100% by weight of diisobutylketones (DIBK and i-DIBK).

According to a first embodiment, the diisobutylketone stream to hydrogenate comprises from 30 to 70% by weight of diisobutylketone (DIBK), from 5 to 30% by weight of isomers of diisobutylketone (i-DIBK), from 0 to 15% by weight of methylisobutylketone (MIBK), from 0 to 5% by weight of acetone, from 0 to 5% by weight of phorone, and from 0 to 15% by weight of mesityl oxide (MO). This stream generally directly comes from the process of preparation of MIBK from acetone.

According to this first embodiment, acetone (DMK) is converted to isopropanol (IP A), methylisobutylketone (MIBK) and mesityl oxide (MO) are converted to methylisobutylcarbinol (MIBC), phorone and diisobutylketone (DIBK) are converted to diisobutylcarbinol (DIBC), and diisobutylketone isomer (i-DIBK) is converted to diisobutylcarbinol isomer (i-DIBC).

According to another embodiment, the diisobutylketone stream to hydrogenate is pure DIBK and/or a mixture of DIBK isomers, that is to say that the total quantity of DIBK plus i-DIBK is more than 70% by weight of DIBK + i-DIBK, preferably more than 85% by weight, and more preferably more than 95% by weight. In this stream, i-DIBK represents advantageously less than 40%, more preferably less than 30% and even in some cases less than 5% by weight.

According to a preferred embodiment of the process of the invention, a new stream of diisobutylketone to hydrogenate is added at each subsequent addition of catalyst. The addition of a new stream of diisobutylketone to hydrogenate is preferably done before the subsequent addition of catalyst and after the removal of the converted diisobutylalcohol. This stream advantageously represents 80-100 % of the initial quantity of diisobutylketone stream to hydrogenate.

Recovering of the converted product

According to the invention, the converted diisobutylalcohol fraction is removed from the reactor before each subsequent addition of catalyst. Advantageously, the quantity of converted diisobutylalcohol fraction which is removed from the reactor represents more than 80% of the initial quantity of diisobutylketone stream to hydrogenate, preferably more than 90% by weight.

Purification

Once the reaction is over, the converted diisobutylalcohol fractions derived from DIBK crude (DIBK crude means DIBK, acetone, MIBK, MO, phorone) can be collected and joined together to be purified in a distillation column.

From this column, DIBC with a purity of at least 90% by weight can be obtained.

When DIBK purified is used as starting material, the product hydrogenated does not require additional purification. Advantages

With the process according to the present invention as defined above, there is no loss in the conversion of DIBK. This advantage allows to keep the activity of the catalyst constant and to obtain a DIBC containing less than 30% of isomers of DIBC, when starting from crude DIBK containing i-DIBK, which satisfies the requirements for certain applications.

For processes using DIBK purified as raw material the performances is as good as the performances for DIBK crude.

Example Step 1:

3% by weight dry weight of RaNi^® (1.5g) is added in a reactor containing around 50g of DIBK purified (>90% by weight of DIBK + i-DIBK). The reactor is closed, heated to 150°C and hydrogen was introduced to 20 bar pressure. The reactional time is controlled by the hydrogen consumption. The product (DIBC + i-DIBC) is obtained in >90% by weight of DIBC + i-DIBC (see Table 1).

Step 2:

For the next batch, the DIBC obtained in the Example 1 is removed, and 0.5g RaNi^® dry weight (1% by weight, 4% by weight accumulated) is added on and a new charge of 50g of DIBK(>90% by weight of DIBK + i-DIBK) is also added. The reactor is closed, heated to 150°C and hydrogen was introduced to 20 bar pressure. The product (DIBC + i-DIBC) is obtained in >90% by weight of DIBC + i-DIBC (see Table 1 ).

Step 3-7:

For the next batch, the DIBC obtained in step 2 is removed and 0.5g RaNi^® dry weight (1% by weight, 5% by weight accumulated) is added on and a new charge of 50 g of DIBK(>90% by weight of DIBK + i-DIBK) is also added. The reactor is closed, heated to 150°C and hydrogen was introduced to 20 bar pressure. The product (DIBC + i-DIBC) is obtained in >90% by weight of DIBC + i-DIBC (see Table 1).

Step 3 is repeated (step 4 to 7) until the catalyst concentrations achieve 10% by weight (dry weight).

Step 8 and 9

At each step (batch) after having reached 10% by weight of catalyst, 1% by weight of catalyst is removed and 1% by weight of fresh catalyst is added. A new charge of 50 g of DIBK (>90% by weight of DIBK + i-DIBK) is also added. The reactor is closed, heated to 150°C and hydrogen was introduced to 20 bar pressure. The product (DIBC + i-DIBC) is obtained in >90% by weight of DIBC + i-DIBC (see Table 1).

This procedure is kept for all over batches.

Table 1 Batch

Data

1 2 3 4 5 6 7 8 9

% Convection DIBK -> DIBC 92.6% 94.5% 93.9% 89.1% 94.9% 94.6% 95.0% 95.7% 95.5%

% Convertion i-DIBK -> i-DIBC 98.8% 98.4% 99.5% 98.6% 98.8% 98.7% 99.0% 98.8% 98.9%

Global Convertion(%) DIBK TOTAL -> DIBC TOTAL 94.4% 95.6% 95.6% 91.9% 96.0% 95.8% 96.2% 96.6% 96.5%

RaNi concentration (%w/w)^a 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0% 10.0% 10.0%

"Dry weight

Conclusion: The conversion into DIBC is constant all along the process (for DIBK and i-DIBK). Comparative example with a one-step addition of 10% of catalyst at the beginning

Table 2

Batch

Data

1 2 3 4 5 6 7 8 8

% Convertion DIBK -> DIBC 97.4% 92.8% 84.5% 76.6% 81.5% 73.8% 68.1% 68.9% 71.8%

% Convertion i-DIBK -> i-DIBC 99.3% 99.5% 99.3% 99.3% 99.3% 99.5% 99.3% 99.2% 99.4%

Global Convertion(%) DIBK TOTAL - DIBC TOTAL 97.9% 94.7% 88.7% 83.0% 86.5% 81.0% 76.9% 77.4% 79.6%

RaNi concentration (%w/w)^a 10.0% 10.0% 10.0% 10.0% 10.0% 10.0% 10.0% 10.0% 10.0% ^a Dry weight

Conclusion: The conversion into DIBC decreases all along the process (for DIBK and not for i- DIBK).

Claims

1. Process for the production of diisobutylalcohol by hydrogenation of diisobutylketone in a reactor in presence of hydrogen and a metallic catalyst, wherein:

• the addition of the catalyst in the reactor is a fractionated addition,

2. Process according to claim 1, wherein the catalyst is chosen in the group consisting in a metal selected from rhodium, ruthenium, and, nickel, more specifically Raney Nickel^®.

3. Process according to claim 1 or 2, wherein the catalyst is Raney Nickel^®.

4. Process according to anyone of claim 1 to 3, wherein the fractionated addition comprises at least 2 additions considering the initial quantity of catalyst introduced as the first addition.

5. Process according to anyone of claims 1 to 4, wherein the total quantity of catalyst present in the reactor at the end of the fractionated addition reaches from 5 to 15% by weight relative to the weight of the diisobutylketone stream to hydrogenate, preferably from 8 to 12% by weight.

6. Process according to anyone of claims 1 to 5, wherein the initial quantity of catalyst in the reactor corresponds to 1 to 5% by weight relative to the weight of the diisobutylketone stream to hydrogenate, preferably to 2 to 4% by weight.

7. Process according to anyone of claims 1 to 5, wherein the number of subsequent additions of catalyst to the reactor is from 1 to 60.

8. Process according to anyone of claims 1 to 7, wherein the reactor is maintained at a temperature between 80 to 200°C, preferably from 120 to 170°C.

9. Process according to anyone of claims 1 to 8, wherein the pressure in the reactor in maintained between 0.5 and 3 MPa.

10. Process according to anyone of claims 1 to 9, wherein the time between each addition of catalyst correspond to the time necessary to reach >90% of conversion of the diisobutylketone.

11. Process according to anyone of claims 1 to 10, wherein the diisobutylketone stream to hydrogenate comprises from 30 to 100% by weight of diisobutylketone.

12. Process according to anyone of claims 1 to 11, wherein the diisobutylketone stream to hydrogenate comprises from 30 to 70% by weight of diisobutylketone (DIBK), from 5 to 30% by weight of isomers of diisobutylketone (i-DIBK), from 0 to 15% by weight of methylisobutylketone (MIBK), from 0 to 5% by weight of acetone, and from 0 to 15% by weight of mesityl oxide (MO).

13. Process according to anyone of claims 1 to 12, wherein the converted diisobutylalcohol fractions are collected and joined together to be purified in a distillation column.