New direction of research for industrial catalysis — An example of mitsubishi chemical corporation

Science and Technology in Catalysis 1998 Copyright © 1999 by Kodansha Ltd.

New Direction of Research for Industrial Catalysis — An Example of Mitsubishi Chemical Corporation

Takeru ONODA Mitsubishi Chemical Corporation, 2-5-2 Chiyoda-ku, 100 Tokyo, Japan

Abstract Recent trends of research on industrial catalysis are summarized with several examples of research and development at Mitsubishi Chemical Corporation (MCC). Various factors requested for research on catalysis at MCC are clarified considering targeted business areas and the business environment surrounding us. As our recent trends to accelerate technology development, four examples; concurrent technology development, computational chemistry, hybrid process development, and development of new hydrogenation processes are introduced. Our future direction of research on catalysis are also mentioned at the end. 1. INTRODUCTION The research on catalysis has been progressing in close relation with its industrial application. On the other hand, chemical industry has been changing extremely dynamically, in sync with economic environment. The most important decision for the research on catalysis in a company will then be, "what research should be done ? " And the decision will include how to invest limited resources on which research areas and "what should not be done". Businesses which closely relate to research on catalysis are the businesses on synthetic chemicals, environment catalysis, petroleum refining, and catalyst production and sales. MCC limits its business only on synthetic chemicals, which can be further classified into two categories: petrochemicals and fine chemicals. Those two businesses have distinguished characteristics. Business situation of petrochemicals for any Japanese chemical companies, however, is extremely grave in general. There are mainly two reasons. First, smallness in production scale and high production cost structure, due to high labor costs and distribution costs, act unfavorably. Second, the matured domestic market. Disappointingly, it is plain that Japan has very little attractiveness as a production site for petrochemicals. Circumstances are the same for MCC, even we own three ethylene centers of which each are 50 thousand tons in capacity. Influence of petrochemical business at MCC, however, is exceedingly large. In fact, we depend almost one half of our sales on the petrochemical business. In addition, serious consideration must be made on the fact that many of our production of chemical products depend on the infrastructures of these ethylene centers. Thus, efforts to maintain the petrochemicals business is very demanding. In order to strengthen global competitiveness of the business, three ethylene centers need to be reorganized in accordance with the long term business strategy, and production cost must be reduced through rational alliances of business and production. Also important is to further strengthen the development technology for the promising business segments. Selected and 33

34 T. Onoda

prioritized business segments must be globally strengthened with the powerful support from the highest technology standard. On the other hand, fine chemical business is becoming more and more important. It is one of the most favorable business areas where chemical company can practice technology to produce performance chemical products. In order to lead and make a sound business, highly advanced chemical synthesis technology will be essential. Catalysis technology is recognized as one of the most important key technologies. Managing of hybrid process, which is the hybrid of organic synthesis, biosynthesis, and catalysis, is a strong tool especially for the fine chemical business areas. Acceleration of technology development is also a basic success factor for this business area. 2. TRENDS IN MCC'S RESEARCH ON CATALYSIS As examples of our recent activities, acceleration of technology development, computational approach in chemistry, hybrid process development, and development of new hydrogenation processes shall be mentioned. 2.1. Acceleration of Technology Development A key word for the process development at MCC is the concurrent technology developments. Formerly, engineering development of production process was operated after obtaining a certain insight on catalyst development. In other words, conventional technology development was a linear model. With the aid of progress in high performance computing, parallel catalysis development and process development became effective. The non linear approach aims optimum process design and the shortest path to success, through relevant suggestion and amendment of catalysis development direction in view of total process economy. For enforcement, shared concept of technology fusion as shown in Fig.l is most important [1]. Speed up & cost reduction

of technology

development

Concurrence Catalyst D e v e l o p m e n t i ^ Reaction Analysis — Process Analysis — Process Synthesis —

Technology Development

. ^ - C o s t Engineering • ^ - E q u i p m e n t Diagnosis • ^ - S a f e t y Engineering •
-Cr O n e Organization

o [Research, Development. Engineering & Production Technology

J

Figure 1 Technology Fusion To develop one industrial process, many elemental technologies are demanded. These individual technologies are merged and must be simultaneously developed. Thus, first of all, the organizational partition walls in a company must be lowered enough so as to enable the staff of each technology to concentrate on one shared goal. At MCC, prompt and flexible development is attempted by synthesizing three functions of research, development and engineering in one organization, "technology development". Moreover, many of the technology elements must be maintained at the highest standards, and must be flexibly applied to simultaneous technology development. To reserve everything within a company is neither possible, nor efficient. In many aspects, impeccable outsourcing of the world class function is necessary. In other words.

35

propriety of simultaneous technology development depends on the optimum outsourcing. New process development of acrylonitrile production from propane, which MCC is currently intensifying its resources, is a typical example in which outsourcing technologies play important roles. As shown in Fig.2, propane recovery, an important step to achieve high selectivity to acrylonitrile which is the feature of the new process, is jointly developed with the BOC Group, Inc. and many other elemental technologies are also polished through outsourcing of professional knowledge and technologies to universities and other professional organizations world wide.

[—I C3H8 Recovery

h^

Catalyst: IP-2 (T0CAT3) Process: IP-4 (T0CAT3)

* BOC Joint Develop.

Reaction

[03^8

1 NH.; J

Products L Absorption J

Separation Purification

• Process Synthesis * Simulation Model

• Reaction Analysis * Reactor Design

(02/Air]

-•AN

* Simulation Model

* Outsourcing

Figure 2 New Process Development for Acrylonitrile Production from Propane 2.2. Computational Approach in Chemistry Computational application to engineering development has already been established and it is widely recognized as the most effective methodology for saving cost and time for process development. However, effectiveness of computational catalyst design is still insufficient, especially in the field of heterogeneus catalyst design, and there are still many problems to be overcome. On the other hand, it can be a powerful tool especially for the precise design of ligands, where extremely complicated ligands must be precisely designed for the optimization of metal complex catalysts. This is because trial and error approach by chemist's experience or inspiration is becoming more and more difficult for an efficient catalyst development. As an example, recent results of improvement on catalysts for propylene 0x0 reaction are mentioned bellow. AG^(NBD) CH3CH2CH2CHO

NBD

CH3CHCH3

IBD

CH3CH=CH2 + CO + H2 Rhcat AG*(IBD) CHO

P-Ligand modified rhodium complex catalysts are commercially used for the propylene 0x0 reaction. In order to produce the profitable NBD selectively, many kinds of catalysts have been developed, of which success depends on how to design the P-ligands. As shown in Table 1, AAG^(=AG*(IBD) - AG^NBD)) values, which determine the selectivity of the two aldehyde isomers, NBD and IBD, are very small (AGMs a free energy of activation). Thus high level calculations become indispensable for the design of new catalysts which can control such required A AG* values.

On the bases of detailed investigations about the reacfion mechanism

together with calculations (molecular mechanics method), structures of bisphosphite ligands, which can give a high NBD/IBD ratio (NBD/IBD>100 for some ligands), were suggested and

36 T. Onoda

verified experimentally [2]. Investigation of possibilities of these ligands as a commercial catalyst using a pilot plant is now in preparation.

Table 1

NBD/ffiD and A AG* Values in Propylene Oxo Reaction

AG * = AG' (ffiD) - AG' (NBD), temp. = 70°C NBD/IBD AAG*

1

10

20

30

40

50

100

500

0.00

1.57

2.04

2.32

2.52

2.67

3.14

4.71

kcal / mol

t

Bisphosphite Ligands

<^<^ NBD/ffiD

6

tt

g^-^-sS {^jt'r^)^ (^)rH°^. 32

96

147

2.3. Hybrid Process Development Although some recent progress in the field of metal complex catalysts are impressive, biosynthesis using biocatalysts is the most appropriate reaction in order to achieve both high regioselectivity and stereoselectivity. By combining biosynthesis, organic synthesis and catalysis, an extremely efficient hybrid synthesis for a target compounds can be realized. 2.3.1. Production of S-aminomethyl-l-chloropyridine (CPMA) Expansion of fliture demand for CPMA is expected as a synthetic intermediate for performance chemicals, such as agricultural chemicals, pharmaceuticals, and liquid crystal materials. Due to the attractive potential of CPMA, various synthetic routes have been proposed by many chemical companies and several technologies have been developed. But these reaction routes were very complex and none has been successful in commercial scale application. At MCC, a lot of research work was launched when an extremely simple and commercially advantageous synthetic route was recognized. The conception was to use 3-cyanopyridine (3CP) as a cheap raw starting material and route the breakdown of 3CP to 3-cyano-5-hydroxy-pyridine (3CHP) using hybrid process. Even though the organic synthesis was thought to be difficult and the possibility of biosynthesis was unknown, the research project was launched.

..iT Synthesis

J CPMA

NH2

37

A great increase in productivity was achieved [3] when a new microbe (Comamonas testosterni MCI-2848) was discovered Also inducers and reaction stimulators were discovered by investigating the details of the reaction. In 1995, commercial production of CPMA was accomplished for the first time in the world using technologies of both chlorination using thionyl chloride by acid-amide catalyst and hydrogenation by modified Raney-Ni catalyst. It took half a year to find out a new strain for CMPA production and it took another one year to ship products into the market after total process development. Even though the scale of this business is not so large, in terms of ROA (Return on Asset), this business is excellent. Understanding consumer demands, finding original and efficient synthesis route, and speed of technical development, are the key for success for the business. What we should always keep in mind, however, is that the life of this type of business can be short because of severe technology competition among the customer products and competition from newcomers. 2.3.2. Process development for L-Aspartic acid production Various derivatives are obtained from polymerization and chemical modification of L-aspartic acids. Due to their biodegradability, these derivatives have potential for commercial application as detergents, chelating agents, adsorbents, and water treatment agents. A rapid expansion of demand is expected once cheap commercial production process for L-aspartic acid is established. MCC supplies maleic anhydride and production process of L-aspartic acid form maleic acids is now under development as one of its derivatives. H^

Aspartase

Isomerase

C

/ H

HOOG

HOOC^ ^H

^COOH C

H

Maleic acid

NH3

C

or Acid catalyst

\ COOH

COOH

H-C-H I H-G-NH2 COOH L-Aspartic acid

Fumaric acid

Maleic acid is isomerized to fumaric acid by acid-catalyst, and then aspartase converts fiimaric acid and ammonia to L-aspartic acid. Taking advantage of physiological characteristics (non-lytic properties under non-growing conditions) of Coryneform bacteria MJ-233, 'natural immobilization' system was adopted for L-aspartic acid production. An aspartase activity is maintained stable for several months. The separation and recycling of cells from the reaction mixture is done by an ultrafiltration system. In order to improve the productivity of the process, recombinant DNA technologies are being applied to Coryneform bacteria MJ-233 as shown in Fig.3. [4] Wild Cell

Recombinant Cell

0.5|jm

Figure 3

Improvement of Productivity of Cells

38 T.Onoda

Bioprocess which is the core of MCC's process is shown in Fig.4. L-Aspartic acid is crystaUzed by adding fumaric acid to reaction solution. Fumaric acid and ammonia is converted to aspartic acid under the presence of recycled cells. The efficiency of this process is very high, giving up to several thousands ton / m3 / year. At MCC, the enzyme life and productivity rate have been certified on the pilot plant already. And feasibility studies for commercial scale production are now underway.

ultrafiltration

Maleic acid

Product

Separation

acidI ( catalyst

Enzyme Fumalic acid - ^ (FA)

FA Crystallization

Reaction H"* NH3

L-Aspartic acid Enzyme: Naturally Immobilized Aspartase

Figure 4. New Process for L-Aspartic Acid Production

2.4. Development of New Hydrogenation Processes Recently, development of new hydrogenation processes has been very active. Bellow are some of the examples from MCC's developments. 2.4.1. Hydrogenation of succinic anhydride to y-butyrolactone MCC has a long history of gammabutyrolactone (GBL) business. In 1971, GBL was coproduced with tetrahydrofiiran by liquid phase high pressure hydrogenation by using Ni-Re suspended catalyst. The production of GBL by this process, however, was terminated after tetrahydrofiiran was produced by the new butadiene process. Thus, for the manufacturing of GBL, a new gas phase low pressure hydrogenation process had to be developed. To fiirther rationalize and increase production, however, the new process was replaced by low pressure liquid phase hydrogenation process, using a new homogeneous Ru-complex catalyst. The newest process was industrially applied with a great success in 1997 with the capacity of 10,000 TA".

It is well known that Ru-complexes have extremely high hydrogenation activity, and many research are reported on the hydrogenation of aldehydes and ketones. But, there are scarcely any report on hydrogenation of acid anhydrides. Very few examples of RuCl2(PPh3)3 and Ru2Cl4(dppb)3 were known, but their efficiency was insufficient for industrial application. Additionally, halogen-contained complex reflects another disadvantage as commercial catalysts. Therefore, we made a wide screening of new Ru-complexes, and found cationic complexes, [HRu(PR3)n]^X', as promising complexes. One of the big advantage of these complexes is that

39

targeted Ru-complexes are formed by in situ reaction under the presence of hydrogen, using Ru(acac)3, PR3 and HX as the raw materials. Finally, P(octyl)3 as PR3 and p-toluenesulfonic acid as HX were chosen. Exceedingly high activity and selectivity to GBL were achieved by removing water that forms during the reaction process with hydrogen gas flow. Selectivity of GBL by this new process reached 96% which enabled more than 20% cost reduction compared to that of the conventional process. The new process is the world's first large scale hydrogenation technology using Ru-complex catalysts. 2.4.2. Hydrogenation of aromatic carboxylic acids to aldehydes [5] Aromatic aldehydes are important intermediates for the production of organic fme chemicals, such as pharmaceuticals, agrochemicals, and perfumes. These aldehydes have been produced mainly by halogenation methods. However, these methods have several disadvantages, such as poor yields and undesirable by-products. Carboxylic acids and their derivatives can be hydrogenated to alcohols on Cu-Cr catalyst under high pressure, but aldehydes cannot be prepared in this method. Based on a preliminary survey of various metal oxides, zirconia (Zr02) was found to be a potential catalyst because of its high selectivity to aldehydes. By modification with Pb^"^, In^^ Cr^^, or Mn^\ the activity of the Zr02 was remarkably enhanced. Unmodified Zr02 was deactivated during hydrogenation by coke formation, but the modified Zr02 accumulated a smaller amount of coke during the reaction. Cr^^ modified Zr02 was used for the hydrogenation of various carboxylic acids and results are given in Table 2. Various aromatic aldehydes are commercially produced at MCC, using the new process in multi-purpose plant. Table 2 Hydrogenation of Various Carboxylic Acids with Cr^^ modified Zr02 Catalyst Conversion of acids (%)

Selectivity to aldehydes (%)

Benzoic acid

98

96

o-Methylbenzoic acid

98

97

/7i-Phenoxybenzoic acid

97

96

Dimethyl terephthalate

64

73

/7y-Chlorobenzoic acid

82

77

Carboxylic acids or esters

2.4.3. Hydrogenation of aliphatic carboxylic acids to aldehydes [6] Unsaturated aliphatic aldehydes are not only widely used as fragrances, but also are important intermediates in the production of specialty chemicals such as pharmaceuticals and agrochemicals. These aldehydes have been conventionally produced by the synthetic methods in which large amount of halogen and alkaline metal is used. So far, direct hydrogenation of carboxylic acids was performed under catalysts such as r-Al203, Cu-Cr, Zr02, but these are only applicable for the hydrogenation of aromatic or sec-, tert-aliphatic carboxylic acids. When applied to primary or unsaturated carboxylic acids, only low selectivity was obtained. The hydrogenation of 10-undecenoic acid was performed under series of metal oxides. Only highly pure Cr203 exhibited an excellent selectivity towards the corresponding aldehydes without migration of C=C double bond. Cr^^ modified Zr02 catalyst showed good selectivity for aldehyde formation, but the products became a mixture of C=C migrated isomers.

40 T. Onoda

Highly pure Cr203 showed excellent activity and selectivity for the hydrogenation of various aliphatic aldehydes as is shown in Table 3, which indicates the wide applicability of this catalyst. In MCC, a series of aliphatic aldehydes such as 10-undecenyl aldehyde are commercially produced since 1996.

Table 3 Hydrogenation of Various Aliphatic Carboxylic Acids with Cr203 Catalysts Carboxylic acids

Decanoic acid

Temp. (°C)

Conversion Selectivity to aldehydes (%)

350

91

97

Dodecanoic acid

350

97

96

Octadecanoic acid

350

98

93

9--Octadecenoic acid

350

96

97

Cyclohexanecarboxylic acid

370

92

98

10-Undecenoic acid

370

74

98

3. TASKS AHEAD OF MCC'S RESEARCH ON CATALYSIS We were reviewed by the Technology Advisory Board, which consists of outside professionals, this spring. The following four items were recommended as the future tasks of our research on catalysis development. First, a challenge to polyfunctional catalysts. What it means is the precise designing of active sites of solid catalysts, which will be a difficult task for commercial catalysts. Second, the combination of homogeneous and heterogeneous catalysts. Through the research of supported homogeneous catalysts, it was discovered that the support for the homogeneous catalyst is no longer considered to be an inert spectator, but it provides the additional role of providing a specific catalytic function. The second task will be just as hard as the first one for commercial catalysts, but setting the right target reaction that will trade off and exceeds the efforts on catalyst development may lead breakthroughs. Third, the combination of heterogeneous catalysis and biotechnology. We are already intensifying our efforts as mentioned earlier. Fourth, combinatorial catalysis and robotics. It is obvious that the methodology is very important for catalyst development. It will be necessary to deepen the skill in this area along with the feed backs from the outsourcing activities world wide.

4. REFERENCES [1] Y. Natori and L.O'Young, 1st PTEC Symposium (Mitsubishi Chem. Corp.), September 1996. [2] Y Urata, H. Itagaki, E. Takahashi, Y Wada, Y Tanaka and Y Ogino, Japan Koukai Patent, 1998-45776. [3] M. Yasuda, T Sakamoto, R. Sashida, M. Ueda, Y Morimoto and T Nagasawa, Biosci. Biotech. Biochem., 59 (1995)572. [4] M. Terasawa, and H. Yukawa, in: Industrial Application of Immobilized Biocatalysis, Marcel Dekker, Inc., New York, 1993, p37. [5] T Yokoyama, T Setoyama, N. Fujita, M. Nakajima and T. Maki, Appl. Catal. A: General, 88(1992)149. [6] T Yokoyama, Nikkakyo Geppo, April, 1997, pl4.