Hydrogenation of N,N-dimethyl-2-propenylamine over nickel catalysts supported on various metal oxides

Applied Catalysis, 4

(1982) 87-96 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

HYDROGENATION

OF N,N-DIMETHYL-2-PROPENYLAMINE

VARIOUS

METAL OXIDES

Hideshi

HATTORI,

Department

(Received

Hisaya

19 October

OVER NICKEL CATALYSTS

SUPPORTED

ON

and Kozo TANABE

IVAI

of Chemistry,

87

Faculty of Science,

1981, accepted

Hokkaido

University,

Sapporo

060, Japan.

20 July 1982)

ABSTRACT Hydrogenation supported

of N,N-dimethyl-2-propenylamine

on various

of supports Zr02, A1203,

Generally,

of hydrogen Ni supported

high activities

though Ni/Si02-Al203 extremely

high.

Si02-Al203

amine was observed Al203 catalyst.

however,

high activity.

nickel titrated

with

on solid acid catalysts,

In particular,

the activity

poisoned

the formation

of Ni/MgO was

by C02, whereas

the Ni/

of N,N-dimethyl-l-propenyl-

but was not appreciable

catalyst.

types

did not correlate

of metallic

two D atoms were incorporated

and with the Ni/Si02-Al203

of various

such as MgO, CaO, La203, and Th02

Ni supported

was completely

over the Ni/MgO catalyst

In the deuteration,

over the Ni/Si02both with the Ni/

With the Ni/Si02-A1203

catalyst,

was located on each carbon atom 2 and 3, while with the Ni/MgO

0 atom was on carbon atom 2 and a half on each carbon atom 1 and 3.

It was concluded merized

with

the influence

of catalysts

nor the amounts

During hydrogenation,

one D atom

catalyst,one

adsorbed

out over nickel catalysts

used were MgO, CaO, La203, Th02,

The activities

as compared

showed

to examine

The supports

on solid base catalysts

The Ni/MgO catalyst

was not.

MgO catalyst

oxides

activity.

Ti02, Si02, and A1203.

with the amounts I2* exhibited

kinds of metal

upon catalytic

was carried

to yield

that over Ni on solid bases, N,N-dimethyl-2-propenylamine

N,N-dimethyl-1-propenylamine

give N,N-dimethylpropylamine, amine was directly

hydrogenated

to produce

On the basis of this conclusion, Ni on MgO in a non-aqueous

0166-9834/82/0000+000/$02.75

which easily

underwent

while over Ni on solid acids,

was iso-

hydrogenation

to

N,N-dimethyl-2-propenyl-

N,N-dimethylpropylamine.

a highly active catalyst

was prepared

medium.

0 1982 Elsevier Scientific Publishing Company

by mounting

INTRODUCTION Selective in organic

hydrogenations

synthesis

of compounds

and are also of importance

particularly,

in perfume

hydrogenation

of nitro compounds,

many basic reactions. hydrogen

Although

nitriles,

electrons

on nitrogen

unsaturated presented metallic

probably

atom with the catalyst containing

selective

nitrogen,

of alkenes,

has scarecely

been studied

in the hydrogenation

of unsaturated

interaction

surface.

and selectivity

on proper supports.

of

compounds

of the lone pair of

So far, for hydrogenation

catalysts[l,2].

of

Pd have been

With conventional

by the reactant

mechanisms

of metallic

Thus, we have attempted

for hydrogenation

Ni on different

Ni/Si02-A1203

nitrogen

NiB and borohydride-reduced

heterogeneous

involve of

nitrogen.

such as Pt., Pd, and Ni, poisoning

MgO, and on Si02-A1203 different

all of which

are

and complexities

were unavoidable[3,4].

catalysts

supporting

importance

may be the addition

of catalysts

because of a strong

In many cases, the activity when mounted

containing

The behaviors

as active and selective catalysts

containing

reactions

of fields of industry,

of industrial

and amines,

from those in the hydrogenation

compounds

of hydrogenolosis

amides,

are important

have been done for hydrogenation

compounds

catalysts.

are different nitrogen,

in a variety

Among the reactions

investigations

of unsaturated

containing

nitrogen

One of the simple basic reactions

extensive

over heterogeneous alkenes

industry.

to C=C double bonds in compound

hydrogenation

containing

of unsaturated

types of metal oxides.

exhibited

high activities.

were involved

in the reaction

to obtain

compounds

were improved highly active and

containing

nitrogen

It was found that Ni supported A mechanistic

study revealed

for the Ni/MgO catalyst

On the basis of these results,

catalyst.

catalysts

an extremely

by on

that

and the

active catalyst

was designed.

EXPERIMENTAL Catalyst

METHOOS

preparation

Supported

Ni catalysts

oxides with an aqueous are summarized air for 6 h.

were prepared

nickel nitrate.

in Table 1.

by impregnation

of various

The preparative

methods

Prior to impregnation,

The metal oxides were suspended

water was evaporated was then decomposed

to dryness

over a water

at 500°C in air for 3 h.

the metal oxides were calcined

in aqueous bath.

kinds of metal

for the metal oxides

nickel nitrate,

in

and the

Nickel nitrate on the metal oxides

The contents

of Ni are also given in

Table 1. For preparation

of Ni/MgO, another method was also employed.

(150 mg) was dissolved which was obtained was stirred

by calcination

for 6 h.

During the procedures, sysrem.

into 100 ml ethyleneglycol. of Mg(OH)2

Ethyleneglycol

Nickel hydroxide

To this solution,

589 mg MgO,

at 500°C, was added, and the suspension

was distilled

out under a reduced

care was taken to prevent moisture

pressure.

from introduction

into the

89 TABLE 1 Preparation

of catalysts

Catalyst

and surface.properties

Preparation

of support

Ni content

Amount of H2

wt %

adsorbed

Percentage metallic

Starting material

Pr;i;;;;{sn

Ni/MgO

Mg(OH)*

A

9.1

0

Ni/CaO

CatOH)*

A

9.1

0.1

-

Ni/La203

La( N03)3

B

9.2

0.6

-

Ni/Th02

Th(NO3)4

A

9.1

0.9

-

Ni/Zr02

ZrOC12

B

9.1

0.2

-

0

Ni/Ti02

Tic14

B

9.2

0.8

11.5

Si(OC2H5)4

B

9.1

12.8

36.8

Ni/A1203

commercial

Ni/Si02-A1203

commercial(Nikki

washing 2): Measured

Adsorption

Measurement

of H2 was measured

of metallic

The amount

16.5

in air, B; Precipitation

volumetrically

the catalyst

with NH4GH followed

by

at O°C in the pressure

was outgassed

range 0~15 Torr

for 1 h and reduced with -4 at 500°C to less than 10 Torr.

by outgassing

at 5OOY

nickel content

of metallic

acid according

Ni was measured

to the method

by the reaction

of Gravel1

with 12 in dilute hydro-

et al.[5].

procedures

A microcatalytic

pulse reactor was used for carrying

About 30 mg of catalyst H2 stream at 5OOY

was placed

for 3 h.

N,N-dimethyl-2-propenylamine

was injected

The products

evaporated

into a gas chromatographic

were trapped

Apiezone

L on KOH-treated

purified

by passage

Chromosorb

through

In some experiments,

to the reaction by a syringe

column.

sieves

was outgassed

with an

1 pR of the

trap for 15 min and flash

A 4.5-m glass column

W was operated

a closed recirculation

and pretreated

temperature,

into an H2 stream ahead of the

in a liquid nitrogen

13 X molecular

Sixty mg of catalyst

out most of the experiments.

in an U-tube quartz reactor

After cooling

catalyst.

was used.

24.5

4.0

in air.

a 100 Torr of H2 for 3 h, followed

Reaction

-

by I2 titration.

the measurement,

chloric

9.1

of hydroqen

Adsorption Before

10 N631L)

decomposition

and calcining

Ni*)

10-5mol/g

Ni/Si02

1): A; Direct thermal

of

at 68V.

packed with

The H2 stream was

kept at liquid

nitrogen

temperature.

reactor with a volume of about 900 mll at 500°C, treated with 100 Torr of H2 at

90

5OO'C for 3 h, and outgassed dimethyl-Z-propenylamine

at 500°C again.

of N,N-dimethyl-2-propenylamine The products were separated collected

separately

subjected

to NMR analysis.

was carried

in a liquid nitrogen

Si02-A1203

experiments

catalyst.

and evacuated

trap.

100 u% of N,N-

to react at 25“C. recirculation

A part of the collected

reactor.

sample was

in CDClq and a shift reagent

until all peaks were separated.

spectrometer

Deuteration

column and each product was

The sample was dissolved

on an R 206 Hitachi

Poisoning

containing

out in the closed

by a gas chromatographic

(Eu-FOD) was added in small portions measured

A mixture

and 100 Torr of H2 was allowed

The spectrum

was

at 60 MHz.

with CO2 were performed

After pretreatment,

for the Ni/MgO catalyst

5 Torr of CO2 was adsorbed

and the Ni/

on the catalyst

at 0°C for 30 min.

Hydrogenation

of 1-butene was carried

out in a microcatalytic

Injection

of the reactant was done by manipulating

syringe.

The products were analyzed

propylene

carbonate

a stop cock instead

by gas chromatography,

on Celite being operated

pulse reactor

at O'C.

of use of a

a 10-m column

packed with

at 0°C.

RESULTS Adsorption

of hydrogen and amount of metallic

The H2 adsorption The v, values measured

for catalysts

by titration

measured,

data obeyed

amounts

amine obtained

result

Ni

A-nong the catalysts

detectable

amounts

the

did not adsorb

of metallic

Ni.

of N,N-dimethyl-2-propenylamine to N,N-dimethylpropyl-

pulse reactor are plotted against consisted

exclusively

such as propene and dimethylamine small.

bond migration

was not detected

from the first pulse.

conversion.

The Ni/Si02-A1203

of N,N-dimethylpropylfrom

that might

under the conditions

employed.

on MgO, CaO, La203, and Th02 exhibited

In particular,

the Ni/MgO catalyst

also showed high activity

the activities

the pulse

which might result

The N,N-Dimethyl-1-propenylamine

As shown in Figs. 1 and 2, Ni supported activities

these five catalysts,

in Table 1.

adsorption.

of metallic

the largest amount of H2 and contained

of N,N-dimethyl-2-propenylamine

The products

were negligibly

from double

for dissociative The amounts

On the other hand, the Ni/MgD catalyst

with a microcatalytic

The other products

decomposition

adsorbed

Ni.

conversions

number in Figs. 1 and 2. amine.

in Table 1.

of H2 nor did it contain

for the hydrogenation

The percentage

nickel isotherm

with I2 are also included

largest amount of metallic

Activity

are included

the Ni/Si02 catalyst

any appreciable

the Langmuir

after the 4th pulse.

were in the following

Ni/Zr02>Ni/A1203>Ni/Ti02>Ni/Si02

order;

high

showed 100 % Besides

Ni/MgO NifCaO Ni/La203 NilThO2 60 -

0"""" 12345678

"1

345678

2

Pulse number

Pulse number

Fig. 1 (left) and 2(right) Catalytic activities of Ni supported oxides for the hydrogenation of N,N-dimethyl-2-propenylamlne

With the Ni/Si02-A1203, completely

adsorbed

Ni/Al203,

on the catalysts

and Ni/Zr02.

the reactant

at the first pulse.

established

until the 5th pulse for the Ni/Si02-AT203,

and Ni/Si02

catalysts.

Activities

for the hydrogenation

The percentage 1-butene against 3.

to butane

conversions

on different

and products

Material

Ni/A1203,

were

balance was not

Ni/Zr02.

Ni/Ti02,

of 1-butene

of

are plotted

the pulse number in Fig.

The most active catalyst

was the Ni/Si02

catalyst,

which

showed the lowest activity the hydrogenation

for

of N,N-

dimethyl-2-propenylamine. the contrary, catalyst,

On

the Ni/MgO

which was most active

for the hydrogenation

of the

amine, was least active hydrogenation

for the

of 1-butene.

The

orders of the activities

of the

catalysts

for

were different

the hydrogenation

of N,N-

dimethyl-2-propenylamine the hydrogenation

and for

of 1-butene.

2

3

4

5

6

Pulse number

Catalytic activities of Ni supported Fig. 3 on different oxides for the hydrogenation of 1-butene

92 Effect of reduction The catalytic catalysts.

temperature

activities

The variations

dimethyl-2-propenylamine

on the activity

also varied with the reduction of the percentage

are shown in Fig. 4 for the Ni/MgO, Ni/A1203, reduction showed

temperature

a maximum

when reduced

differed

activity

reduction

temperature

increased

with the reduction

completely

depending

The activity

increase

temperature

in the reduction

inactive when reduced

in the temperature

Variation

Effect of the amount

in TABLE 2. decrease

catalyst

was active

activity

catalyst

at the

gradually

, attaining a maximum at 800°C and decreasing temperature.

The Ni/MgO catalyst 100 % conversion

was when reduced

temperature/"C for the hydrogenation

as a function

of reduction

of N,Ntemperature

of Ni in Ni/MgO on the activity

of the Ni/MgO catalysts

The activity

as the amount

5 % Ni, the production migration

of the Ni/Si02

The optimum

The NiO catalyst

with a maximum

below 35O"C, but showed

of activities

dimethyl-2-propenylamine

The activities

The Ni/A1203

of N,N-

temperature

range of 500-8OO'C.

Reduction Fig. 4

for the hydrogenation of the reduction

on the types of support.

range of 200-8OO"C,

of 350°C.

of the

Ni/SiO, and NiO catalysts.

when reduced at 250°C.

in the temperature

with a further

conversions

at the 5th pulse as a function

temperature

was observed.

increased

exceeded

containing

as Ni content

30 I.

different

increased

amounts

up to 9 %, and began to

With the Ni/MgO catalysts

of N,N-dimethyl-1-propenylamine

of Ni are given

containing

that resulted

7 % and

from double

bond

93 TABLE 2 Activities

for hydrogenation

different

of N,N-dimethyl-2-propenylamine

Ni contents

Amount

of Ni,

Conversion,

Reaction

%

over a mixture

TO examine

%

0

5

0

31

7

9

20

30

50

70 100

100

98

94

of MgO and Ni/Si02

the reactivity

of N,N-dimethyl-l-propenylamine

N,N-dimethyl-2-propenylamine

was passed

MgO catalyst

catalyst,

and the Ni/Si02

31 mg of the Ni/Si02. migration convert

of 2-propenylamines

Time dependence The product

converted

hydrogenation,

30 mg of the MgO was placed ahead of

was very active

for double bond was supposed

at the end of the MgO catalyst

catalyst

of the

the hydrogenation

could be tested.

to

zone.

of N,N-dimethyl-l-

The result

indicated

30

50

that

to N,N-dimethylpropylamine.

of products

of N,N-

dimethyl-2-propenylamine recirculation

in a

reactor

from those obtained

in a microcatalytic reactor.

M .

pulse

The time dependence

of the product

composition

the hydrogenation

the Ni/MgO catalyst in Fig. 5.

in

over

is shown

The reactant

completely

disappeared

0

was rapidly

formed in 5 min and disappeared.

10

20

Reaction

in 5

N,N-Oimethyl-l-

propenylamine

5

.r

of N,N-

dimethyl-2-propenylamine

gradually

toward

bed that consisted

distributions

for the hydrogenation

differed

a catalyst

[6], N,N-dimethyl-2-propenylamine

of the catalysts,

over the Ni/Si02

95 % of the reactant

min.

in which

to N,N-dimethyl-1-propenylamine

propenylamine

through

Since the MgO catalyst

Thus, by this arrangement

closed

over Ni/MgO with

40

time/ min

Fig. 5 Time dependence of the hydrogenation of N,N-dimethyl-2-propenylamine over Ni/MgO o; reactant, 0 ;N,N-dimethyl-1-propenylamine, A; N,N-dimethylpropylamine.

The

amount of N,N-dimethylpropylamine steady rate. A1203,

increased

at a

In the hydrogenation

the formation

of N,N-dimethyl-2-propenylamine

of N,N-dimethyl-1-propenylamine

over the Ni/Si02-

was not appreciable.

94

Poisoninq

by CO2

The Ni/MgO catalyst was completely hydrogenation

Deuteration

occurred.

poisoned

The Ni/Si02-A1203,

No double

by COP.

on the contrary,

bond migration

was not poisoned

over Ni/MqO and Ni/Si02*2c3

In the deuteration incorporated

of N,N-dimethyl-Z-propenylamine,

into N,N-dimethylpropylamine

for the Ni/Si02-A1203

catalyst.

the average

numbers

catalyst,

the positions

while over the Ni/MgO catalyst, were distributed

of D atoms

were 1.96 for the Ni/MgO catalyst

The conversions

and 2.00

were 100 % for both catalysts.

numbers of D atoms located on each carbon atom are listed in TABLE 3. Si02-A1203

nor

by CO2.

of D atoms were limited

The

Over the Ni/

to carbon atoms 2 and 3,

one D atom was located on carbon atom 2 and the rest

on carbon atoms 1 and 3.

TABLE 3 Location

of D atoms in N,N-dimethylpropylamine

in deuteration

of N,N-dimethyl-2-

propenylamine

Number of D atoms on each carbon 1)

Catalyst

Total

C(1)

C(2)

C(3)

Ni/MgO

0.32

1.11

0.49

1.96

Ni/Si02-A1203

0.03

0.80

1.17

2.00

1):

(CH,),=N-C(l)-C(2)-C(3)

DISCUSSION The activities -2-propenylamine

of the supported were dependent

Ni catalysts

CaO, La203, and Th02, are known to possess promote

base-catalyzed

reactions

these basic metal oxides seem to participate

In the hydrogenation is roughly

Actually

the activity

amounts

in some way. it is commonly

some interaction

for the Ni supported

Ni catalysts

supports.

observed

Therefore,

roughly

on the surface.

correlated

with the

of N,N-dimethyl-2-propenylamine,

the

either with the

Ni, even when the comparison

it is suggested

and changed

later.

that the catalytic

did not show any correlation

with the support

on

The basic sites on supports

to the numbers of Ni atoms exposed of 1-butene

MgO,

and to

This point will be discussed

or with the amounts of metallic

was made among non-basic received

higher activities.

In the hydrogenation

of the supported

of H2 adsorbed

basic sites on their surfaces

for the hydrogenation

of H2 adsorbed.

activities amounts

of olefins,

proportional

of N,N-dimethyl

Among the supports,

There is a tendency

[7~10].

to exhibit

in the reaction

activity

for the hydrogenation

upon the type of support.

that the Ni atoms

in nature.

95 The activity catalyst

of the catalyst

with Hp.

reducibility

Vedrine et al. reported

of Ni2+ ions ’ changes

on Si02 were most easily temperatures catalysts

found between

the reducibility

With the Ni/MgO catalyst, 300°C is reminiscent Pretreatment

temperature

Comparison Si02-A1203

catalyst

the hydrogenation product

over the Ni/MgO catalyst,

the Ni/Si02-A1203

deuteration

catalyst

were limited

Ni/SiO,-A1203

catalyst,

whereas

over the Ni/MgO catalyst

catalyst,

was not.

for the Ni catalysts

supports

Scheme

on basic metal

was produced

the locations

strongly

was observed

I.

Ni/basic

II. Ni/non-basic

bond migration

indicate

that the reaction

of N,N-dimethyl-P-

hydrogenated

supports

to yield

C=C-C-N;

C hydrogenation WC-C-C-N/~ C (Ni)

in hydrogenation

of allylamines

Therefore,

and the Ni catalysts

C hydrogenation C-C=C-N' ------6-C-C-N= 'C (Nil

'C

N,N-

for double bond migration

on basic metal oxides.

support

over the

on carbon atoms 1,2, and 3

the reaction

on non-basic

support

,C double bond migration * (basic site) 'C

by C02,

of 0 atoms on

and that, over the Ni/Si02-A1203

was directly

basic

of

as a primary

poisoned

could be drawn as follows.

C=C-C-N

Scheme

on

on basic metal oxides.

of Ni supported

Since basic metal oxides are active of double

as the

First, the time dependence

via double bond migration

is likely to occur over Ni supported schemes

Third,

These observations

involvement

that

with those of the Nil

atoms 2 and 3 of N,N-dimethylpropylamine

N,N-dimethyl-2-propenylamine

of allylamines,

over Ni supported

D atoms were distributed

proceeded

isomerization

This suggests

the Ni/MgO was completely

to N,N-dimethyl-1-propenylamine

dimethylpropylamine.

[6].

of the Ni/MgO catalyst

were observed.

Second,

to carbon

over the Ni/MgO catalyst.

propenylamine

such as I-butene

while only N,N-dimethylpropylamine

catalyst:

above with

of N,N-dimethyl-2-propenylamine

the characteristics

differences

on pretreatment

of the MgO catalyst

showed that N,N-dimethyl-1-propenylamine

over the Ni/Si02-A1203 while

by pretreatment.

will clarify

and Ni/Si02

It seems likely that the basic sites on

in the hydrogenation behaviors

The

temperature.

of allylamines

for the hydrogenation

of the catalytic

Three distinct

reduction

reactions

and Ni/MgO.

Ni/MgO,

of the activity

bond migration

that the

There was no relation

of the activities

for base-catalyzed

are involved

of the

The Ni2+ ions supported

Ni/A1203,

respectively.

the appearance

basic sites on MgO appeared

[ll].

of the Ni/A1203,

and the optimum

double

the Ni/MgO became active

supports

by Ni/Ti02,

and 8OO"C,

of the variation

[12,131, and especially

the support

followed

activities

3SO", SOOO-800°,

temperature

on the basis of XPS observation

on different

reduced,

that gave maximum

were

oxides.

varied with the prereduction

C C

96 Since enamines migration, a mixture

are reactive

it should easily of MgO and NilSi

hydrogenation

of composition

was faster than the successive

by the lack of H2 adsorption.

could be prepared

caused a low concentration

aqueous

the rapid hydrogenation

observed

over

of enamine.

(Fig. 5) indicates

hydrogenation.

The

It is expected

on the that a

if large numbers of Ni atoms can be deposited

It is known that Ni ions form a solid solution

may occur during

is formed by double bond

The high conversion

may be due to the small numbers of Ni atoms being exposed

a theory supported

highly active catalyst on MgO.

supports

the time dependence

that the double bond migration slow

once the enamine

hydrogenation.

catalysts

Over the Ni/MgO catalyst,

MgO support,

reagents,

undergo

of Ni atoms on MgO.

with MgO.

The penetration

This may have

of Ni ions into MgO

of MgO with an aqueous nickel nitrate. Use of non2+ . solution may prevent Ni ions from penetrating into a bulk of MgO.

Therefore,

impregration

a new catalyst was prepared

by impregnation

of MgO with an ethyleneglycol

solution

of Ni(OH)2. The resulting catalyst adsorbed hydrogen, the vm value being -5 3.0 x 10 mol/g, and exhibited high activity; 100 % of N,N-dimethyl-2-propenylamine converted Fig. 5.

into N,N-dimethylpropylamine Obviously

the Ni/MgO catalyst

in 5 min under the same condition prepared

as shown in

by this method was the most active

catalyst.

ACKNOWLEDGEMENT This work was supported from the Ministry

by a Grant-in-Aid

of Education,

Science

for Specific

Project

Research

No. 311706

and Culture.

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a 9 10 11 12 13

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