Ruthenium promoted hydrodenitrogenation catalysts

Applied Catalysis, 34 (1987) 311-316 Elsevier Science Publishers B.V., Amsterdam -

RUTHENIUM

PROMOTED

HYDRODENITROGENATION

A.S. HIRSCHON* , R.B. WILSON Chemistry

International,

333 Ravenswood

20 January

CATALYSTS

Jr., and R.M. LAINE*

Organometallic

(Received

311 Printed in The Netherlands

Program,

Physical

Ave., Menlo

1987, accepted

Organic Park,

15 June

Chemistry

Ca. 94025,

Department,

SRI

U.S.A.

1987)

ABSTRACT The promotion of a commercial CoMo hydrotreating catalyst with an active amine transalkylation catalyst, Ru3(C0)12, was investigated. The resulting catalyst, RuCoMo, exhibited enhanced HDN activity on quinoline and gave a 5-fold increase in selectivity to aromatic hydrocarbon products. Unlike bulk ruthenium, the ruthenium promoted catalyst was sulfur tolerant.

INTRODUCTION The products nitrogen,

of coal

sulfur

transformed nitrogen

liquefaction

and oxygen

into a useful

amounts

of hydrogen

could economically hydrogenation would

due to concurrent

aid in making

Considerable

as quinoline HDN reactions

ruthenium

synfuels

effort

through

however,

to promote

HDN C131. We report

commercial

hydrotreating

exhibit

enhanced

0166-9834/87/$03.50

activity

attractive

catalysis

catalysts

catalyst

mechanisms models

and bulk metal

to establish

by such

we have modelled

for carbon-nitrogen

catalysis that

bond cleavage.

of bulk ruthenium

whether

a sulfided

ruthenium,

even in the presence

0 1987 Elsevier Science Publishers B.V.

source.

containing

the ability

that

to aromatic

et al. Cl41 indicate

(CoMo), when doped with

and selectivity,

that

crude oil and

HDN reaction

[IO-121

poisons

here attempts

excessive

Given

energy

HDN catalysts

and those of Shabtai

is that sulfur

consume

in preference

on nitrogen

these commercial

is one of the most active problem,

can be

that extract

of aromatics.

in elucidating

catalysts

transalkylation studies,

the coal liquid

processes

the cost of refining

a more economically

Cl-91. To improve

of

in HDN and HDO, any catalyst

of these bonds

has been spent

amounts

oil or coal liquids

hydrogenation

reduce

HDN hydrotreating

C131. These modelling

A severe

cleavage

significantly

before

catalytic

are the slow steps

promote

would

use of commercial

The current

(HDO) from crude

C-N and C-O bond cleavage

have significant

that must be removed

fuel.

(HDN) and oxygen

processes

will

of added

sulfur.

._

A

1

3H2

C3H7

a-

3 m

NH2

1

C3H7

H2

IL_--

FIGURE

Y H

r-f

Quinoline

HDN reaction

network.

RESULTS The HDN reactivity prepared

by doping

quinoline major

of the sulfided

the sulfided

as a model

hydrocarbon

compound.

products:

The ideal HDN catalyst having

low hydrogenation

products.

Therefore

(4 moles

key measure

catalysts,

used in this study, moles

of metal

product

formation,

benzene

(PB). Under our conditions

Figure

RuCoMo

undergoes

1 were observed, of THQ,

catalyst.

propylcyclohexene constant catalyst.

the proportion (7 moles

during

activity

using two

while

aromatic

of propylbenzene

H2 required)

we calculated

represents

the turnover

in catalyst/hour

a

carbon-nitrogen

bond cleavage

All of the intermediate

(PCHE),

was followed

in Table

the appearance

of PB increases

HDN with

which

converted

is formed

shown

by monitoring

in the

1 the TF for the disto 141 for the

of PCH increases

as a minor

or is

and DHQ then under-

from 9 to 27,

from 0.5 to 8.0. The concentration

the CoMo catalyst

to THQ

to propylaniline

and products

from 54 for the CoMo catalyst,

Simultaneously,

(PCH) to propyl-

is rapidly

(DHQ). Both propylaniline

and the HDN reaction

frequencies

* 10% based on

(THQ) or for HDN hydrocarbon

the quinoline

PCH and PB. As seen

of THQ increases

and the appearance

compared

HDN provides

produce

as well as the ratio of propylcyclohexane

HDN reactions.

concentrations appearance

selectively

for loss of tetrahydroquinoline

to decahydroquinoline

go subsequent

were

1, quinoline

consumption.

rates)

then either

ruthenium

and the catalyst

and propylbenzene.

and should

to propylcyclohexane

substrate/total

hydrogenated

with

have high C-N bond cleavage

initial

which

CoMo catalyst

in Fig&e

propylcyclohexane

would

activity

of hydrogen

For the comparisons (TF, moles

CoMo catalyst As shown

in comparing

H2 required)

commercial

product,

and is not observed

of

remains almost . with the RuCoMo

314 TABLE

1

Turnover

frequencies

a& .

THQ

Catalyst

PB

PCH 8.9

0.5

RuCoMo

141

26.9

8.0

RuCoMo

142

27.4

5.7

130

36.9

4.4

CoMo

54.0

(sulfided RuCoMo

200°C)

(CS2)'

aMoles product/total moles of metal in catalyst/h. b Calculated for first 10% of reaction. '0.33 mmol CS2 added

TABLE

to reaction

mixture.

2

Hydrocarbon

distribution

at 5 mol% conversion

of quinoline

to hydrocarbon

pro-

ductsa. Catalyst

%PCH

CoMo

%PB

%PCHE

82.2

4.6

RuCoMo

76.6

23.4

0

RuCoMo

81.0

19.0

0

(H~S/H~

13.2

200~~)

aReaction

of IO ml 0.197 M quinoline

in h-hexadecane

and catalyst

at 350°C and

500 psig H2.

We also determined found

that conversion

100) than with quinoline

and its HDN products were

Surprisingly,

(hydrogenation

for the active

of formation

of PB and PCH without similar

hydrogenation

competitive

line under HDN conditions. genated

under

identical

conditions

the concurrent

the RuCoMo

forml'ng benzene.

of benzene.

competes

Thus,

of

(CHE) to quino-

rapidly

hydro-

CoMo gave slower

under

very

the rates

hydrogenation

cyclohexene catalyst

of PB

the RuCoMo

low, with a TF of

Thus we can compare

studies , we added

In this case,

formation

sites.

considering

CHE to PCH (TF = 95) without

(TF = 22), also without

TF = 93.4) apparently

(TF =

of

a mixture using

was quite

and

catalyst

the influence

on the rate of PB hydrogenation,

the rate of PB hydrogenation

0.7. The 6-methylquinoline

In

with the RuCoMo

(TF = 14). To determine

treated

successfully

PB to PCH.

of PB under HDN conditions,

of PB to PCH was far faster

the CoMo catalyst

and 6-methylquinoline catalyst.

the rate of hydrogenation

rates

our conditions,

any

315 PCHE that is formed is not observed,

with the RuCoMo

and we can assume

catalyst

is rapidly

hydrogenated

to PCH and

that PB comes only from the HDN of tetrahydro-

quinoline. To determine activity flowing

if sulfiding

and selectivity,

we sulfided

We sulfided

H2S/H2.

the ruthenium-promoted the RuCoMo

as highly

dispersed

were nearly

identical

to those without

added

to the same reaction

although

there were more

ruthenium In

to compare

under equivalent mined

to provide

to

product

in Table

2. Thus,

CoMo catalyst,

to 23.4% for the RuCoMo

hydrocarbon

product

reaction

in Table

and to keep

1, the TF values disulfide

HDN catalysis

was

was enhanced,

bulk ruthenium,

is sulfur

tolerant. for the two catalysts

of PB, PCH and PCHE were to hydrocarbons

we see an increase catalyst

the

at 200°C under

distributions

conversion

and are listed

retard

sintering

Thus unlike

the concentrations a quinoline

would

When carbon

sulfur,

of the CoMo catalyst

conditions,

We have taken the RuCoMo

sulfiding. excess

products.

the relative

by extrapolation

to avoid

As shown

as possible.

aliphatic

in the presence

order

catalyst

at low temperatures

the cluster

catalyst

deter-

of 5 mol%,

of PB from 4.6% for the

of the total

up to 50% conversion

hydrocarbon

and observed

product.

the same

distribution.

DISCUSSION These

results

that cleave

show that the addition

C-N bonds

CoMo HDN catalyst agree with catalyst

in amine

greatly

In comparison

catalyst

is higher.

The major

increased

aromatic

savings

greater,

content

in H2 consumption

nitrogen-containing catalyst

Under similar

that might

aromatics).

HDN conditions,

carbonyl

to a savings

this estimate

supported

from decreased an additional

neither

on alumina

there seems

to be a synergistic

and RuCoMo,

that leads to a more active

sulfur work.

tolerant. However,

The exact mechanism

these

the need to develop mum amount

effect

preliminary improved

of hydrogen

sulfided

rating

consumption

hydrogenation benefit

are highly

than PCH.

promoted

catalyst

catalysts,

Thus, RuMo

that is also

require

significant

that can remove

of non-

of the RuCoMo

[I31 nor

will

the

any potential

activity.

of the promotion

results

however,

bulk ruthenium

and selective

of

products

any C-N cleavage

in the ruthenium

HDN catalysts

consumption.

octane

exhibit

aromatic

of 10% in hydrogen

result

has a higher

is the activity

in excess,

Furthermore,

RuMo

[14,15].

towards

does not consider

results

high C-N as well

not only

PCH, is still

product,

amounts

is that the PB produced

ruthenium

selectivity

CoMo catalyst,

a commercial

These

that a sulfided

demonstrate

but also the selectivity

hydrocarbon

HDN (although

showed

to catalysts

[lO,lll,to

of the catalyst.

techniques

ring hydrogenation

to the non-promoted

the RuCoMo

for quinoline

versus

wetness

a precursor

reactions

the activity

et al. who recently

by incipient

as C-O hydrogenolysis

transalkylation

enhances

those of Shabtai,

prepared

of Ru~(CO),~,

more detailed

with regard

nitrogen

to

with a mini-

316 ACKNOWLEDGEMENTS We would Technology

like to thank the Department Center

DE-FG-85PC80906.

for support

of Energy,

of this work through

Pittsburgh grants

Energy and

DE-FG22-93PC60781

We would also like to thank NSF for partial

support

and

of this work

through grant CHE 82-19541.

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