Catalytic Conversion of Propane to Ethene

N23

tive. 5. Any products methane

(e.g.

made directly

methanol)

will

more reactive than methane almost

certainly

undesirable

siastes, ‘The race is not always to the swift,

from

nor battle to the strong” -

be much

tend to react further to

end products.

On the Meaning of Surface Area Meas-

First he deals with the most effective way at present

of getting

ducts from methane, ming for ammonia

chemical

ture, which currently direct oxidation

urements for Microporous

BET surface

manufac-

uses about 7% of all

workers,

despite recent claims in the area. Oxidative been

to e.g.

the subject

ethene,

of intense

work in the past few years, suggests

that there

Benson

process,

world-wide

of about

methane

lems: how feasible is it to handle the enormous

quantities

of concentrated

chloric acid generated

during the reaction?

“Despite the enormous

contribution

by chemists in academia but intractable producing viable.

of reacting

meth-

we are a long way from

a process that is commercially

This

chemical

made

to the fascinating

problem

ane selectively,

hydro-

is where

engineer

ancial constraints

the

working

chemist

and

under the fin-

of industry have a major

par-t to play.” Parkyns describes soline process tive coupling

of methane,

as possibly

process nearest to commercial

metal

the

(J.A. Cape and

Kibby, J. Colloid

Interface

Sci., 138

a timely analysis

Nitrogen

adsorption

of

experi-

ments were carried out at 77 K and 0.0050.74 atm on a series of Na-Y zeolite/ &-alumina mixtures ranging from pure zeolite to pure alumina. The results showed that the conventional porous

BET surface area of a micro-

solid,

catalyst,

(mesopores term

such

as zeolite

and macrostructure)

proportional

term was calculated and depended

vol-

factor in the latter

from a simple model,

on the pressures

the BET fit. A consistent areas and micropore

used in

methodology

for obtaining

BET equation

area and a

to the micropore

ume. The proportionality

developed

cracking

is the sum of an external

external volumes

was

surface from the

and t-plots.

Catalytic Conversion

of Propane to

Ethene

realisation,

with complex

photocatalysis

and bio-

catalysis are 21 st century commercial

pro-

jects at best. He concludes:

“I therefore

leave you with the quotation

from Eccle-

Recent US patents

Volume 67 No. 2 -

(Nos. 4929791 and

4929790) to W.W. Keading

and E.W. Va-

lyocsik of Mobil Oil Co. describe a catalytic process for converting

propane

to ethene

over either zeolite ZSM-23 or ZSM-50. Productivity

may be increased

ing the catalyst applied catalysis -

routine

paper with the title above

on dear crude oil

gas. Reactions

hydrides,

is zeolite

the

the Arco gas-to-ga-

(GTG), which uses oxida-

but even this depends and cheap

known

results. A recent

the subject.

to

but there are clearly prob-

have

(1990) 515) contains

30%. The

via chloromethanes,

who

method gives misleading CL.

but Parkyns

converting

high octane gasoline is very attractive

has

may be an inherent

limit of C2 products

are

measure-

with a metre rule. An exception

still looks a difficult goal,

coupling,

area measuremtints

usually taken as unambiguous

ments, almost as ifthey had been obtained

in the UK. The

of methane to oxygenates

such as methanol

Materials

pro-

that of steam refor-

and methanol

the natural gas consumed

methane

but, as the cynic

has added, ‘that’s the way to bet”.”

itself and will

3 January

1991

either by treat-

with SOa (either prior to

N24

cracking

or with catalytic

cracking). 600°C

amounts

Temperatures

with

remarkable

ethene. For example,

during

vary from 500 to selectivities

to

with ZSM-23, having

a SiC2/A1203 ratio of 83:1, and with SOn pretreatment,

the selectivities

wt.-%toethene,

were

46.3

18.3wt.-%topropeneand

29.4 wt.-% to methane

carbons

and toxic pollutants

must equal

20%. Fleets of automobiles

of 10 or more

in the two dozen smoggiest

cities must run

80%

today’s

more

mobiles

cleanly

than

only

auto-

Trucks must be 50% cleaner!

the area of toxic emissions,

at 10% conversion

by 15%. By

the year 2000, the reductions

regulated

seven

In

the existing law

chemicals

(since

with a WHSV of 3.46 h-’ at 600°C. At 600°C

1970); however,

with a WHSV of 0.86 h-‘, they obtained

that, over the next ten years

52% conversion

the polluting plants must use the best tech-

with ca. 30% selectivity

to

ethene and 31 wt.-% to methane,

the new law stipulates

nology available formaldehyde

of U.S. Clean Air Law

of

to reduce their emissions

of 189 chemicals Highlights

a majority

by 90%. Benzene

must be controlled.

spect to acid rain: a total

and

With re-

of 111 of the

dirtiest power plants in 21 states must cut No doubt about

the

changes

many

of you

recent

have

legislation

of, and

heard

emissions

to the

clean air laws in the United States. The Wall Street

dioxide

1990 (pages Al

of Monday,

and A7) provided

useful comparisons the original

October

29, some

of the existing law vs.

proposal

by President

Bush

emissions

by utilities is imposed

oxide emissions

by 2 million tons a year

(about 25%), beginning that this pioneering

gress and signed by the President. While it

impact upon catalysis

would be inappropriate

many new opportunities

here, some of the more significant ards with regard to tailpipe 1994 automobiles of the nitrogen

oxides

hydrocarbons;

tailpipe

acti-

for

Methane Activation

of 30%

standards

now

for 10 years

100,000 miles as opposed

The

or

to the current 5

years or 50,000 miles; warranties

on pollu-

to existing law,

5 years and 50,000 miles.

In the area of alternative

underthe

sponsored

research

recently

project

seven different

the aim being to develop oxidation

products

pre-

have

on methane collabora-

laboratories

new catalysts for

of methane

or formaldehyde

been

Community

This project involves

tion between partial

fuels, white there

are no existing requirements

contracts

signed for a major European activation.

now must last 8 years or

80,000 miles, as opposed which stipulates

and offer

for research

and a 40% cut in

have to be maintained

tion equipment

will have an

research

stand-

emissions

with a reduction

in 1995. It is clear

legislation

vities in this area,

portions

with regard to smog were: tougher

by the

cap on the sulfur

by the year 2000! Utilities must cut nitrogen

and the final act as it was passed by Conto list all the details

power plants

must make cuts in sulfur dioxide year 2000. A nationwide

Journal

by the year 1995

and more than 200 additional

regarding

enhancements

sulfur dioxide

to give and/or

C2

meth-

anol and to examine various other aspects

vious laws, the final bill supports a reformu-

of the processes

lation of the gasoline

beds). The partners (with the names of the

(beginning

sold in the nine smoggiest mulation

cities; this refor-

will cut the emissions

applied catalysis -

in 1995) of hydro-

Volume 67 No. 2 -

senior

(e.g. the use of fluidised

investigators

Ruhr University, 3 January 1991

in brackets)

Bochum,

Germany

are the (Man-