Proton-catalyzed reactions catalyzed by hydrogen ion-exchanged layered clays

The invention relates to the use of hydrogen ion-exchanged layered clays in organic reactions which are catalyzed by protons. Such organic reactions include the production of ethers by the reaction of an alcohol with an olefin or an olefin oxide, the production of an ether by the reaction of a primary or secondary aliphatic alcohol or an olefin oxide, the production of an alkyl aromatic compound by the reaction of an aromatic hydrocarbon with an olefin or a C.sub.2 or higher alcohol and the production of an alcohol by the hydration of an olefin.

The present invention relates generally to proton-catalysed organic 
reactions and in particular to the use of hydrogen ion-exchanged layered 
clays as catalysts in organic reactions catalysed by protons. 
Many different types of organic reaction are catalysed by protons or, to 
give them another name, hydrogen ions. Typical of such reactions are 
olefin hydration in which the product is an alcohol, esterification of an 
alcohol with an acid in which the product is an ester and the 
decomposition of organic hydroperoxides, e.g. cumene hydroperoxide in 
which the products are phenol and acetone. Generally the protons are 
provided by the dissociation of a strong mineral acid or a strong organic 
acid. Thus sulphuric acid and para-toluene sulphonic acid have been used 
extensively as catalysts in the industrial production of esters, and 
phosphoric acid, usually supported on silica, is a catalyst commonly 
employed in the commercial production of ethanol. Comparatively recently 
hydrogen ion-exchanged resins have been employed as catalysts in, for 
example, the production of alkanols. 
In the Journal of Physical Chemistry, Volume 44, No. 2, February, 1940, pp 
180 to 184, there is disclosed the preparation of an acid bentonite by 
electrodialyzing a 4 percent suspension of Wyoming bentonite in a cell of 
the Mattson type until the catholyte liquor is no longer alkaline and the 
use of the acid bentonite so-prepared as catalyst in the decomposition of 
hydrogen peroxide. 
It is also known from the complete specification of British Pat. No. 
905,854 to produce tertiary butyl acetate by reacting isobutene with 
acetic acid at a temperature within the range 0.degree. to 100.degree. C. 
in the presence of an acid-activated silicate, which may be a Fullers 
earth, montmorillonite, bleaching earth, clay or kaolin activated by 
treatment with mineral acid. U.S. Pat. No. 4,278,820 describes a process 
for producing a monoalkylene glycol monoether by reacting an alkylene 
oxide having 2 to 4 carbon atoms with an aliphatic alcohol having 1 to 4 
carbon atoms in which the improvement comprises performing the reaction in 
the presence of a solid catalyst resulting from the exchanging of 
exchangeable cations of a clay composed mainly of montmorillonite with at 
least one cation selected from the group consisting of aluminium, 
chromium, manganese, iron, tin and thorium. There is no disclosure in U.S. 
Pat. No. 4,278,820 of the use of a hydrogen ion-exchanged layered clay. 
The introduction of U.S. Pat. No. 4,278,820 defines an activated clay as 
one having enhanced adsorptive characteristics obtained by treating the 
acid clay with a mineral acid. It is also stated that the activated clay 
scarcely contains montmorillonite because the montmorillonite structure is 
broken in the process of acid treatment. 
Thereafter in the Journal of Catalysis 58, 238-252 (1979) Adams et al 
disclosed that metal cation-exchanged water-intercalated clays such as 
metal cation-exchanged water-intercalated montmorillonites will convert 
alkenes to the corresponding bis-sec-alkyl ethers. Although the catalytic 
activity of a variety of metal cation-exchanged clays is described, there 
is no disclosure of a hydrogen ion-exchanged clay. 
We have now found that hydrogen ion-exchanged layered clays catalyse those 
organic reactions which are catalysed by protons. The hydrogen 
ion-exchanged layered clays as used in the process of the present 
invention are to be distinguished from the previously used acid-activated 
clays in that their layered structure is essentially retained and they do 
not contain free mineral acid. Compared with naturally occuring clays, the 
hydrogen ion-exchanged clays have a greater catalytic activity. 
Accordingly the present invention provides a process for carrying out a 
proton-catalysed organic reaction characterised in that there is used as 
catalyst a hydrogen ion-exchanged layered clay. 
A layered clay within the context of the present specification is a clay 
having a lamellar structure with interlamellar spaces disposed between the 
lamellar layers. Typical of such clays is montmorillonite which has an 
idealised stoichiometric composition corresponding to Na.sub.0.multidot.67 
[Al.sub.3.multidot.33 Mg.sub.0.multidot.67 ](Si.sub.8)O.sub.20 (OH).sub.4. 
Structurally it comprises a central layer containing octrahedrally 
coordinated aluminium and magnesium in the form of their oxides and 
hydroxides sandwiched between two layers containing tetrahedrally 
coordinated silicon essentially in the form of its oxide. Normally in 
nature cations are present to compensate for the charge imbalance caused 
by isomorphous substitution of Mg.sup.2+ for Al.sup.3+ in the octahedral 
layer, and/or Al.sup.3+ or other ions for Si.sup.4+ in the tetrahedral 
layers. The octahedral and tetrahedral regions are tightly bound together 
to form a lamellar layer. The space between these lamellar layers, i.e. 
the interlamellar space, in natural clays is normally occupied by 
exchangeable Ca.sup.2+ or Na.sup.+ ions. The distance between the 
interlamellar layers can be substantially increased by absorption of a 
variety of polar molecules such as water, ethylene glycol, amines etc., 
which enter the interlamellar space and in doing so push apart the 
lamellar layers. The interlamellar spaces tend to collapse when the 
molecules occupying the space are removed, for example by heating the clay 
at a high temperature. Both natural and synthetic clays having a layered 
structure are well known and may be used in the process of the invention 
after exchange of the interlamellar metal cations normally associated 
therewith with hydrogen ions. Besides montmorillonites such as bentonite 
and Fullers Earths, other types of suitable clays include hectorites, 
beidellites, vermiculites and nontronite. Preferably the clay is a 
bentonite, such as Wyoming bentonite. 
Techniques for obtaining a hydrogen ion-exchanged material from a cation 
exchangeable material are well known and include: 
(i) exchange with excess hydrogen ions in solution, customarily an aqueous 
solution of a mineral acid, and 
(ii) exchange with an aqueous solution of an ammonium compound to produce 
the ammonium ion-exchanged material followed by calcination to decompose 
the ammonium moiety thereby converting the material to the hydrogen 
ion-exchanged form. 
In the preparation of hydrogen ion-exchanged layered clays we have found 
that there are disadvantages associated with the aforesaid technique (ii) 
arising from the use of elevated temperatures in the calcination step. The 
use of too low a temperature risks incomplete decomposition of the 
ammonium moiety resulting in a clay containing both ammonium and hydrogen 
ions. The catalytic activity of the clay so-produced tends to diminish as 
the proportion of ammonium ions remaining in the clay increases. On the 
other hand, the use of too high a calcination temperature tends to 
collapse the lamellar structure and produce an inactive catalyst. 
Accordingly, it is preferred to produce a hydrogen ion-exchanged layered 
clay for use in the process of the present invention by contacting the 
clay containing exchangeable cations with a solution of an acid under 
ion-exchange conditions. Preferably the solution of the acid is an aqueous 
solution. Suitable acids are mineral acids, including sulphuric acid and 
hydrochloric acid, but other acids, such as carboxylic acids, may be used 
if so desired. The acid may suitably be from 0.5 to 10 molar. Although 
contact of the clay with the mineral acid is preferably effected at or 
near ambient temperature, elevated temperatures which do not destroy the 
layered structure and the catalytic activity of the clay may be employed, 
eg up to about 35.degree. C. The period of contact will depend to some 
extent on the temperature. Typically, at ambient temperature the contact 
period may be in the range 1/2 hour to 3 days. 
Techniques for separating the fully exchanged clay from the ion-exchange 
media and excess ions are well known. Any suitable solid/liquid separation 
procedure can be used. Decantation or centrifugation are two preferred 
methods for solid/liquid separation. After exchange it is preferred to 
wash the exchanged clay until all extraneous acid and cations are removed. 
Thereafter the clay is preferably dried. Although drying is preferably 
effected at elevated temperature, temperatures which cause collapse of the 
lamellar structure should be avoided. Generally, drying temperatures in 
the range 20.degree. to 100.degree. C. are suitable. It is preferred to 
activate the hydrogen ion-exchanged clay before use as a catalyst by 
heating in air at a temperature which does not collapse the layered 
structure, suitably up to 180.degree. C., preferably from 80.degree. to 
150.degree. C. The catalyst may suitably be combined with other compounds, 
for example silica, in order to aid pellet or particle stability. 
Hydrogen ion-exchanged layered clays may be used as catalysts in all 
organic reactions which are catalysed by protons. Advantages arising from 
their use are that they can be readily separated from the reaction mixture 
which renders them useful in continuous processes, and they are less 
corrosive than the conventionally employed strong acids and acid activated 
clays which also contain free mineral acids. We have found the clays to be 
particularly useful catalysts in certain specific organic reactions, such 
as the production of esters by the reaction of an olefin or an olefin 
oxide with a carboxylic acid, the production of ethers by reaction of an 
alcohol and an olefin or an olefin oxide, the production of ethers by the 
reaction of a primary or secondary aliphatic alcohol or an olefin oxide, 
the production of bis-sec-alkyl ethers from alkenes, the production of 
alkyl aromatic compounds by the reaction of an aromatic hydrocarbon and an 
olefin or alcohol and the production of alcohols by the hydration of 
olefins. 
In a particular aspect therefore, the present invention provides a process 
for the production of an ester which process comprises reacting either an 
olefin or an olefin oxide with a carboxylic acid in the presence as 
catalyst of a hydrogen ion-exchanged layered clay under reaction 
conditions which result in the formation of an ester. 
With regard to the olefin or olefin oxide reactant any suitable olefin or 
olefin oxide may be employed. Suitable olefins include ethylene, 
propylene, butenes, pentenes and hexenes, diolefins such as butadiene and 
cyclic olefins such as cyclohexene. Mixtures of olefins such as those 
commonly encountered in petroleum refinery streams such as those obtained 
from the steam cracking of hydrocarbons, e.g. catcracked spirit, may also 
be used if so desired. Suitable olefin oxides include ethylene oxide and 
propylene oxide. The amount of olefin or olefin oxide employed may be 
greater or less than the stoichiometric amount required to react 
completely with the acid. 
Both aromatic and aliphatic carboxylic acids may be used. Suitable 
aliphatic acids include formic, acetic, propionic and butyric acids. Of 
the aromatic acids phthalic acids, especially orthophthalic acid, may be 
employed. Mixtures of acids may also be employed if so desired. 
Preferably the olefin is ethylene, the carboxylic acid is acetic acid and 
the ester produced is ethyl acetate. Ethylene glycol diacetate and 
2-hydroxyethyl acetate can be obtained from the reaction of ethylene oxide 
and acetic acid. 
The process may be carried out in the liquid phase or in the vapour phase, 
preferably in the liquid phase. Reaction conditions which result in the 
formation of an ester will depend on whether the process is carried out in 
the liquid or the vapour phase and to some extent on the nature of the 
reactants. 
In the liquid phase the pressure is suitably any pressure which maintains a 
liquid phase at the reaction temperature. In the case of olefins and 
olefin oxides with suitably high boiling points, e.g. hexene-1, the 
reaction may for example be conveniently carried out at the reflux 
temperature of the reactants and under atmospheric pressure, or at higher 
temperatures and pressures if so desired. The temperature may suitably be 
in the range 20.degree. to 300.degree. C. In the case of ethylene, for 
example, the temperature may be in the range 100.degree. to 300.degree. 
C., preferably 150.degree. to 250.degree. C. Generally, using olefin 
oxides lower temperatures within the aforesaid range may be employed. In 
the case of propylene oxide, for example, the temperature may suitably be 
in the range 20.degree. to 150.degree. C., preferably 50.degree. to 
150.degree. C. Solvents may be employed if desired. Suitable solvents 
include hydrocarbons, e.g. alkanes such as hexane and octane. 
In the vapour phase the conditions must be chosen so that the reactants do 
not liquefy; for example in the production of ethyl-acetate from ethylene 
and acetic acid, the acetic acid must be fed at atmospheric or slightly 
higher pressure otherwise it would liquefy at higher pressures. Generally, 
any temperature which does not result in breakdown of the layered 
structure of the clay may be employed. In the case of the reaction of 
ethylene and acetic acid, for example, the temperature may suitably be in 
the range 120.degree. to 250.degree. C., preferably 140.degree. to 
180.degree. C. For the reaction of ethylene and acetic acid the residence 
time which is defined as: 
##EQU1## 
may suitably be in the range 10 to 60 secs, preferably 20 to 40 secs. 
The process may be carried out batchwise or continuously, preferably 
continuously. The batchwise liquid phase production of ethyl acetate, for 
example, may conveniently be carried out by charging acetic acid and 
catalyst to an autoclave, pressurising the autoclave with ethylene, 
heating the autoclave to the desired reaction temperature and maintaining 
the autoclave at the reaction temperature. The reaction time should not be 
unduly protracted otherwise the selectivity for the conversion of acetic 
acid to ethyl acetate may be adversely affected. Thus at an approximately 
2:1 molar ratio of ethylene to acetic acid, an initial ethylene pressure 
of 55 bar and a temperature of 200.degree. C., the reaction time should 
preferably not exceed 5 hours. At the completion of the reaction the 
catalyst may be separated from the product, suitably by filtration, 
centrifugation or decantation and the reaction product worked up in known 
manner to recover ethyl acetate therefrom. The catalyst may thereafter be 
re-used in a further batch reaction with or without intervening treatment. 
The invention also provides a process for the production of an ether which 
process comprises reacting an alcohol with either an olefin or an olefin 
oxide under reaction conditions which result in the formation of an ether 
in the presence of a hydrogen ion-exchanged layered clay as catalyst. 
Suitably, the alcohol may be an aliphatic, cycloaliphatic or aromatic 
alcohol, which may be mono-, di- or polyhydric. Examples of suitable 
aliphatic alcohols include methanol, ethanol, propanols, butanols, 
pentanols and hexanols. An example of a suitable cycloaliphatic alcohol is 
cyclohexanol and an example of an aryl alcohol is phenol. Diols, such as 
ethylene glycol and propylene glycol and polyols, such as glycerol may be 
used. Mixtures of alcohols and/or diols may be employed if desired. 
With regard to the olefin or olefin oxide any suitable olefin or olefin 
oxide may be employed. Suitable olefins include ethylene, propylene, 
butenes, pentenes and hexenes, diolefins such as butadiene and pentadiene 
and cyclic olefins such as cyclohexene and cyclopentadiene. Preferably the 
olefin is a C.sub.3 to C.sub.6 linear or branched olefin. Mixtures of 
olefins such as those commonly obtained from refinery streams, such as 
those derived from the steam cracking of hydrocarbons, eg cat-cracked 
spirit, may also be used if so desired. Suitable olefin oxides include 
ethylene oxide and propylene oxide. The amount of olefin or olefin oxide 
employed may be greater or less than the stoichiometric amount required to 
react completely with the alcohol. Generally, using an olefin oxide, it is 
preferred to employ a stoichiometric excess of the alcohol in order to 
maximise the yield of desired ether. Preferably the excess of alcohol to 
olefin oxide is from 5:1 to 15:1 (molar). 
In preferred embodiments of the invention mono- , di- or tri-ethylene 
glycol mono alcohol ethers, where alkyl=methyl, ethyl or butyl, are 
produced by reacting ethylene oxide with methanol, ethanol or butanol 
respectively; mono-, di- and tri-propylene glycol monoalkyl ethers are 
produced by reacting propylene oxide with an alkanol; methyl tertiary 
butyl ether is produced by reacting methanol with isobutene and 
2-methoxybutane is produced by reacting methanol with linear butenes. 
The process may be carried out in the liquid phase or in the vapour phase, 
preferably in the liquid phase. Reaction conditions which result in the 
formation of an ether will depend on whether the process is carried out in 
the liquid or the vapour phase and to some extent on the nature of the 
reactants. 
In the liquid phase the pressure is suitably that pressure which maintains 
a liquid phase at the reaction temperature. In the case of olefins and 
olefin oxides with suitably high boiling points, e.g. hexene-1, the 
reaction may for example be conveniently carried out at the reflux 
temperature of the reactants and under atmospheric pressure, or at higher 
temperatures and pressures if so desired. Generally, for olefins the 
temperature may be up to 300.degree. C., preferably 50.degree. to 
250.degree. C. The particular temperature employed within the aforesaid 
ranges will depend upon the nature of the olefin. For example the 
temperatures employed for linear olefins will be higher than those 
employed for the corresponding branched olefins. Using alkylene oxides it 
is preferred to employ generally lower temperatures, which may suitably be 
in the range from room temperature to 200.degree. C., preferably from 
20.degree. to 160.degree. C. 
Solvents may be employed if so desired. Suitable solvents include 
hydrocarbons, e.g. alkanes such as hexane and octane. A preferred solvent 
is sulpholane. 
The process may be carried out batchwise or continuously, preferably 
continuously. 
The invention also provides a process for the production of ethers by 
reacting at elevated temperature a primary or secondary aliphatic alcohol 
or a polyol in the presence of a hydrogen ion-exchanged layered clay. 
With regard to the primary aliphatic alcohol reactant suitable alcohols 
include methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol, 
hexan-1-ol, heptan-1-ol and octan-1-ol. The principal ether in the product 
resulting from the reaction of a primary aliphatic alcohol in the presence 
of the lamellar clays is the corresponding 1,1-ether, though the 
corresponding 1,2-ether, may also be formed. Alkenes and alkene dimers may 
also be formed. Generally the proportion of alkene in the product 
increases as the carbon number of the reactant alcohol increases. 
With regard to the secondary aliphatic alcohol reactant suitable alcohols 
include straight-chain alcohols such as propan-2-ol, butan-2-ol, 
pentan-2-ol, pentan-3-ol, hexan-2-ol and hexan-3-ol and cyclohexanol, of 
which propan-2-ol and butan-2-ol are preferred. The ethers predominating 
in the product resulting from the reaction of alkan-2-ol and alkan-3-ols 
are the 2,2- and 3,3- ethers respectively. Alkenes and alkene dimers are 
also formed. 
The reactant may also be a polyol such as an alkylene glycol. A suitable 
alkylene glycol is ethylene glycol which produces a mixture of dioxan, and 
ethylene glycol oligomers (di-ethylene glycol etc). A preferred alkylene 
glycol is diethylene glycol which produces dioxan in high conversions in 
the presence of the lamellar clay. Additionally mixtures of alcohols 
and/or polyols may be used if so desired. 
The elevated temperature may suitably be in the range 50.degree. to 
300.degree. C., preferably from 150.degree. to 225.degree. C. The process 
may be carried out in the liquid phase or in the vapour phase, preferably 
in the liquid phase. 
The invention also provides a process for the production of ethers by 
reacting an olefin oxide at elevated temperature in the presence of a 
hydrogen ion-exchanged layered clay as catalyst. 
Suitable olefin oxides which may be used include ethylene oxide and 
propylene oxide. Thus, for example, reaction of ethylene oxide yields 
1,4-dioxan and 2-methyl-1,3dioxan and the products from the reaction of 
propylene oxide include 2,5-dimethyl-1,3-dioxan. Other epoxides yield 
cyclic ethers, but alpha,beta-unsaturated aldehydes may also be formed. 
The proportion of unsaturated aldehyde generally tends to increase with 
the carbon number of the epoxide. 
The process may be carried out in the liquid phase or the vapour phase, 
preferably in the liquid phase. The temperature may suitably be in the 
range 15.degree. to 200.degree. C., preferably 80.degree. to 200.degree. 
C. 
The invention also provides a process for the production of a bis-sec-alkyl 
ether by reacting an alkene at elevated temperature with intercalated 
water contained within a hydrogen ion-exchanged layered clay catalyst. 
The conditions under which the reaction may be carried out are described in 
the aforesaid paper by Adams et al in the Journal of Catalysis 58, 238-252 
(1979), which is incorporated herein by reference. 
The invention also provides a process for the production of an alkyl 
aromatic compound by reacting at elevated temperature an aromatic 
hydrocarbon with an alkylating agent selected from olefins and C.sub.2 or 
higher alcohols in the presence as catalyst of a hydrogen ion-exchanged 
layered clay. 
The aromatic hydrocarbon may suitably be benzene, naphthalene or other 
polycyclic aromatic hydrocarbon. Aromatic hydrocarbons substituted by 
alkyl or other functional groups, such as for example, hydroxyl, alkoxy 
and hydroxyalkyl, may also be employed. Preferably the aromatic 
hydrocarbon is benzene or toluene. Mixtures of aromatic hydrocarbons may 
also be employed if so desired. 
The olefin may suitably be a mono-olefin or a diolefin. Suitable 
mono-olefins include ethylene, propylene and butylenes, though higher 
olefins, such as for example propylene tetramer, may be employed. Mixtures 
of olefins may also be employed. A suitable diolefin is butadiene. 
Examples of suitable C.sub.2 or higher alcohols which may be employed 
include ethanol, n-propanol and isopropanol. 
In a preferred embodiment of this aspect of the invention benzene is 
reacted with propylene to produce isopropylbenzene (cumene). In another 
preferred embodiment benzene is reacted with ethylene to produce 
ethylbenzene. In a further preferred embodiment phenol is reacted with an 
alkylating agent to produce alkylphenols. 
Reaction of an aromatic hydrocarbon with an alkylating agent may suitably 
be affected in the liquid phase or in the vapour phase, preferably in the 
liquid phase. Generally, reaction of an aromatic hydrocarbon with an 
olefin may be carried out in the liquid phase at a temperature up to 
400.degree. C., preferably in the range 150.degree. to 300.degree. C. and 
at an elevated pressure sufficient to maintain a liquid phase. 
The process may be operated batchwise or continuously, preferably 
continuously. 
Typically, under continuous flow conditions, benzene may be alkylated with 
isopropylene at a temperature in the range from 100.degree. to 400.degree. 
C., preferably from 150.degree. to 300.degree. C., at atmospheric or 
elevated pressure, preferably from 20 to 50 bar. The molar ratio of 
benzene to propylene may be in the range from about 0.1:1 to 100:1, 
preferably from 3:1 to 15:1. The hydrogen ion-exchanged clay may be any 
suitable size or shape as to ensure good contact with the reactants. 
Suitably, particles or pellets may be employed. The ratio of catalyst 
volume to the liquid feed volume flow rate (residence time) may be up to 5 
hours and is preferably in the range from 1 minute to 2 hours. The 
conditions may be permutated either to maximise desirable products such as 
cumene or diisopropylbenzene or to minimise any unwanted by-products. 
Typically, phenol may be alkylated at a temperature in the range from 
50.degree. to 300.degree. C., preferably from 100.degree. to 200.degree. 
C., at atmospheric or elevated pressure. For example, phenol may be 
alkylated with high boiling olefins, e.g. hexene-1, at atmospheric 
pressure and at about 120.degree. C. in a stirred glass vessel fitted with 
a reflux condenser. Using lower boiling olefins, e.g ethylene and 
propylene, as the alkylating agent, elevated pressures may be employed to 
facilitate contact between the phenol and olefin reactants. Alternatively, 
there may be used other methods of mixing whereby the use of elevated 
pressure can be avoided, for example by bubbling the olefin through molten 
phenol containing the catalyst. 
The invention also provides a process for the production of an alcohol 
which process comprises reacting an olefin with water at elevated 
temperature and pressure in the presence as catalyst of a hydrogen 
ion-exchanged layered clay. 
Suitably the olefin may be a lower olefin such as ethylene, propylene or a 
butylene, though higher olefins and mixtures of olefins may be employed if 
desired. Mixtures of olefins also comprise hydrocarbon fractions which 
contain substantial amounts, eg about 25 to about 90% by weight of 
olefins. Preferably the olefin is ethylene and the product produced by 
reaction with water in the presence of the catalyst is ethanol. In another 
preferred embodiment sec-butanol is produced by reacting linear butenes 
with water. 
In conducting the process of the invention the olefin and water or steam 
may suitably be passed over the catalyst together at a reactant feed rate 
corresponding to a space velocity based on liquid reactants in the range 
of about 0.25 to 10 volumes of liquid feed per volume of catalyst per 
hour, ie about 0.25 to 10 L.H.S.V. The water to olefin mole ratio may be 
in the range of about 1:1 to 500:1 preferably from 5:1 to 400:1. 
The total pressure in the reactor may range from about 50 psig to about 
1500 psig and the temperature may be in the range from 50.degree. to 
400.degree. C. The specific temperature chosen depends on the reactivity 
of the olefin. Thus, propylene and the butenes are considerably more 
reactive than ethylene, and for the former olefins a temperature in the 
range of about 100.degree. to about 240.degree. C. is suitable. For 
ethylene the temperature may suitably be in the range from about 
200.degree. to 400.degree. C. Since low temperatures are associated with 
high values of the equilibrium constant for alcohol formation, it is 
desirable to hydrate at the lowest temperature compatible with a 
reasonable rate of conversion. 
The liquid phase reaction may be carried out in the presence of a solvent. 
A suitable solvent, for example, is ethyl carbitol. 
The process may suitably be conducted in what is conventionally known as a 
"trickle bed" reactor, with at least a portion of the water in the liquid 
phase. Alternatively, the process may be operated in the gas phase. 
The invention will now be illustrated by reference to the following 
Examples. 
All analytical results were determined using gas chromatography and the 
identity of the products was confirmed by comparison with authentic 
materials, mass spectroscopy or nuclear magnetic resonance spectroscopy. 
Generally, analyses are expressed by weight but in some Examples flame 
ionisation gas chromatographic areas are used to express the results. 
PREATION OF HYDROGEN ION-EXCHANGED LAYERED CLAY

EXAMPLE 1 
Sodium bentonite (a Wyoming Bentonite supplied as a fine powder for use in 
drilling muds) was added to a solution of concentrated sulphuric acid (400 
ml) in water (1100 ml) and left at room temperature for 2 days with 
occasional stirring. The clay was separated from the solution and washed 
with water by repeated centrifuging and resuspending in water until the pH 
of the supernatant solution was the same as the distilled water used in 
the washing. The clay was dried at 80.degree. C. in air and ground to give 
a fine powder of hydrogen bentonite. 
Hydrogen ion-exchanged bentonites prepared in the aforesaid manner were 
used in all the subsequent Examples. 
PRODUCTION OF ESTERS BY REACTING AN OLEFIN OR OLEFIN OXIDE WITH A 
CARBOXYLIC ACID 
(A) IN THE VAPOUR PHASE 
EXAMPLE 2 
Granules of hydrogen bentonite were packed in the lower portion of a glass 
reactor tube. A 2:1 molar ratio mixture of ethylene and acetic acid was 
passed over the catalyst which was maintained at 170.degree. to 
180.degree. C. and ambient pressure, the residence time being 30 seconds. 
The effluent vapours were condensed to give a liquid product containing 
22.4% w/w ethyl acetate which had been produced from acetic acid with 
greater than 99% selectivity. 
(B) IN THE LIQUID PHASE 
EXAMPLE 3 
10 g of hydrogen bentonite and acetic acid (80 g) were added to a 
Baskerville 100 ml stainless steel autoclave fitted with a stirrer. The 
autoclave was pressurised with ethylene (approximately 2:1 molar ratio of 
ethylene to acetic acid) so that the required pressure (55 bar) was 
reached at the reaction temperature (200.degree. C.). The autoclave was 
kept at 200.degree. C. for 2.5 hours and then cooled. The liquid products 
were shown to contain 39.8% ethyl acetate formed from acetic acid with 
greater than 99% selectivity. 
EXAMPLE 4 
Hydrogen ion-exchanged bentonite (0.5 g) which had previously been 
equilibrated in a dessicator over granular anhydrous calcium chloride, 
hex-1-ene (5 ml) and acetic acid (1.5 ml) were placed in a standard steel 
reactor of capacity 20 ml. The reactor was closed by a screw cap provided 
with an O-ring seal and immersed up to the screw cap in a silicone oil 
bath which was maintained at 200.degree. C. After 4 hours the reactor was 
removed from the bath, cooled and its contents analysed. The results in 
terms of the weight percentage of the individual products (rounded to the 
nearest whole number) are given in Table 1. 
EXAMPLE 5 
Example 4 was repeated except that acetic acid was replaced by propionic 
acid. 
EXAMPLE 6 
Example 4 was repeated except that acetic acid was replaced by isobutyric 
acid. 
EXAMPLE 7 
Example 4 was repeated except that hex-1-ene was replaced by hept-1-ene. 
EXAMPLE 8 
Example 4 was repeated except that hex-1-ene was replaced by oct-1-ene. 
EXAMPLE 9 
Example 4 was repeated except that hex-1-ene was replaced by 
4-methylpent-1-ene. 
EXAMPLE 10 
Example 4 was repeated except that hex-1-ene was replaced by hex-2-ene. 
The results of Example 4 to 10 are given in Table 1. 
TABLE 1 
______________________________________ 
Weight % of product mixture 
total alkene 
Ex. Alkene Acid alkene 
acid esters 
dimers 
______________________________________ 
4 Hex-1-ene acetic 44 40 14 3 
5 Hex-1-ene propionic 41 30 10 19 
6 Hex-1-ene isobutyric 
34 35 10 21 
7 Hept-1-ene acetic 55 35 8 2 
8 Oct-1-ene acetic 62 23 13 2 
9 4 Mepent- acetic 52 31 9 9 
1-ene 
10 Hex-2-ene acetic 54 24 18 4 
______________________________________ 
EXAMPLE 11 
Example 4 was repeated except that hex-1-ene was replaced by 1,5-hexadiene. 
The product contained 5% ester and 7% alkene dimers. 
EXAMPLE 12 
Example 4 was repeated except that hex-1-ene was replaced by cyclohexene. 
15% of new products were obtained, 10% being ester. 
EXAMPLE 13 
Hydrogen ion-exchanged bentonite (1.5 g) was added to acetic acid (16.5 g) 
in an 100 ml flask equipped with a cardice/acetone condenser and the 
mixture stirred at 60.degree. C. Propylene oxide (16 g) was added dropwise 
over a period of about 4 hours and after a further 30 minutes the reaction 
mixture was analysed. This showed the product to contain propylene glycol 
mono-acetate (about 33%), di-methyldioxans (about 20%), unreacted acetic 
acid and propylene oxide. 
PRODUCTION OF ETHERS BY REACTING AN ALCOHOL WITH AN OLEFIN OR OLEFIN OXIDE 
EXAMPLE 14 
The procedure described in Example 4 was followed except that the hex-1-ene 
and acetic acid were replaced by a 50:50 v/v mixture (5 ml) of hexan-1-ol 
and hex-1-ene. The analysis of the product mixture gave: 
______________________________________ 
wt % of product mixture 
______________________________________ 
Hexenes 46 
Hexanol 10 
1,1-ether 18 
1,2- and 1,3-ethers 
8 
alkene dimers 18 
______________________________________ 
EXAMPLE 15 
5 g of hydrogen ion-exchanged bentonite, hex-1-ene (25 g) and methanol (19 
g) were sealed in a Baskerville 100 ml stainless steel autoclave fitted 
with a stirrer. The autoclave was heated at 150.degree. C. for 2.5 hours, 
then cooled. The liquid products (37.5 g, 85% weight recovered) were 
recovered and shown to contain 2-methoxyhexane (19%) and dimethyl ether 
(7%) as the two major products. The product percentages are based on peak 
areas shown in a flame ionisation gas chromatograph. The gaseous products 
were not examined. 
EXAMPLE 16 
As Example 15 but using ethanol (19 g) instead of methanol. The sealed 
autoclave was pressurised with nitrogen to give a reaction pressure of 50 
bar at 180.degree. C. The autoclave was heated at 180.degree. C. for 2.5. 
hours, and then cooled. The liquid products (35.1 g, 80% weight recovered) 
were recovered and shown to contain 2-ethoxyhexane (23.5%) and diethyl 
ether (8.8%) as the two major products. The product percentages are based 
on peak areas shown on a flame ionisation gas chromatograph. The gaseous 
products were not examined. 
EXAMPLE 17 
5 g of hydrogen ion-exchanged bentonite and methanol (19 g) were cooled to 
-20.degree. C. in the detached bottom-half of a Baskerville 100 ml 
stainless steel autoclave. But-1-ene (ca 30 ml of condensed liquid in a 
cardice cold trap) was added and the autoclave sealed. The autoclave was 
flushed with nitrogen and stirred at 200.degree. C. for 2.5 hours, and 
allowed to cool. The liquid products (7 g, 18% weight recovered) were 
recovered and shown to contain 2-methoxybutane (40%) and dimethyl ether 
(55%) and a little C.sub.4 dimers as the major products. The product 
percentages are based on peak areas shown on a flame ionisation gas 
chromatograph. The gaseous products were not examined. 
EXAMPLE 18 
Hydrogen ion-exchanged bentonite (3.75 g) and ethylene glycol (30 g) were 
sealed in a 100 ml stirred autoclave which was charged with liquid propane 
(40 ml). The autoclave was heated at 175.degree. C. for 2.5 hours where a 
maximum pressure of 35 bar was reached. After coolng and venting the 
liquid products were analysed and the results are shown in Table 2. 
EXAMPLE 19 
Example 18 was repeated except that sulpholane (20 g) was added as solvent 
and 20 g of ethylene glycol was used instead of 30 g. The results are 
shown in Table 2. 
TABLE 2 
______________________________________ 
% w/w in liquid product 
Example Isopropyl cellosolve 
Dioxan Digol Propanol 
______________________________________ 
18 19.9 1.0 9.9 0.7 
19* 46.8 0.4 2.8 2.8 
______________________________________ 
*excluding sulpholane solvent 
EXAMPLE 20 
Example 18 was repeated except that but-1-ene (40 ml) was used instead of 
propene. The results are shown in Table 3. 
EXAMPLE 21 
Example 19 was repeated except that but-1-ene (40 ml) was used instead of 
propane. The results are shown in Table 3. 
TABLE 3 
______________________________________ 
% w/w in products 
Example sec-butyl cellosolve 
Dioxan Digol 
______________________________________ 
20 7.9 1.7 5.8 
21* 27.0 0.5 3.3 
______________________________________ 
*excluding sulpholane solvent 
EXAMPLE 22 
Into a 200 ml stirred stainless steel autoclave was placed methanol (19 g, 
0.59 mole) and hydrogen ion-exchanged bentonite. The autoclave was sealed 
and charged with liquid isobutene (approximately 40 ml, 0.5 mole) and then 
stirred at 80.degree. C. for 2 hours. The maximum pressure obtained was 15 
bar. After reaction, the autoclave was allowed to cool and any gaseous 
products were vented off. The liquid products recovered (46.0 g) contained 
80% by weight of methyl tertiarybutyl ether made in a yield of 
approximately 84% from isobutene. 
EXAMPLE 23 
Hydrogen ion-exchanged bentonite (1 g) was added to a stirred solution of 
ethylene oxide (10 g) in ethanol (25 ml) at room temperature in a flask 
equipped with a dry ice/acetone condenser. A virtually complete conversion 
of ethylene oxide was obtained within 30 minutes and the product contained 
mono-ethylene glycol mono-ethyl ether and diethylene glycol mono-ethyl 
ether (about 3:1 ratio by weight) and unreacted ethanol. 
Comparison Test 
A solution of ethylene oxide (10 g) in ethanol (25 ml) was stirred for 30 
minutes at room temperature in a flask equipped with a dry ice/acetone 
condenser. No ethylene glycol ether products were detected by gas 
chromatographic analysis. 
EXAMPLE 24 
Hydrogen ion-exchanged bentonite (1.5 g) was added to ethanol (100 g; 2.17 
mole) in a flask equipped with a dry ice/acetone condenser. Propylene 
oxide (13.2 g; 0.23 mole) was added dropwise to the reaction mixture which 
was stirred at room temperature. Analysis of the product after a few 
minutes showed virtually quantitative conversion of the propylene oxide to 
mono-propylene glycol mono-ethyl ether and di-propylene glycol mono-ethyl 
ether (about 9:1 ratio by weight). 
EXAMPLE 25 
Example 24 was repeated except that the propylene oxide was replaced by 
ethylene oxide (14 g; 0.23 mole) and the amount of ethanol (123 g; 2.8 
mole) increased. Analysis of the product showed virtually quantitative 
conversion of the ethylene oxide to mono-ethylene glycol mono ethyl ether 
and di-ethylene glycol mono ethyl ether (about 9:1 ratio by weight). 
EXAMPLE 26 
Hydrogen ion-exchanged bentonite (1.5 g) was added to n-butanol (22 g; 0.33 
mole) in a flask equipped with a dry ice/acetone condenser. Ethylene oxide 
(13.2 g; 0.30 mole) was added dropwise and analysis of the product after a 
few minutes showed the product distribution, as measured from gas 
chromatography areas, to be ethylene glycol mono-butyl ether (45%), 
diethylene glycol mono-butyl ether (40%), unreacted butanol (5%) and 
ethylene oxide (10%). 
PRODUCTION OF ETHERS BY REACTING A PRIMARY OR SECONDARY ALIPHATIC ALCOHOL 
OR A POLYOL IN THE PRESENCE OF A HYDROGEN ION-EXCHANGED LAYERED CLAY 
EXAMPLE 27 
Hydrogen ion-exchanged bentonite (0.5 g) which had previously been 
equilibrated in a desiccator over calcium chloride and propan-2 -ol (5 ml) 
were placed in a standard steel reactor of capacity 20 ml. The reactor was 
closed by a screw cap provided with an O-ring seal and immersed up to the 
screw cap in a silicone oil bath which was maintained at 200.degree. C. 
After 4 hours the reactor was removed from the bath, cooled and its 
contents analysed. The results in terms of wt. % of individual products in 
the product mixture are in the following Table 4. 
EXAMPLE 28 
Example 27 was repeated except that butan-2-ol was used in place of 
propan-2-ol. 
EXAMPLE 29 
Example 27 was repeated except that pentan-2-ol was used in place of 
propan-2-ol. 
EXAMPLE 30 
Example 27 was repeated except that hexan-2-ol was used in place of 
propan-2-ol. 
EXAMPLE 31 
Example 27 was repeated except that butan-1-ol was used in place of 
propan-2-ol. 
EXAMPLE 32 
Example 27 was repeated except that pentan-1-ol was used in place of 
propan-2-ol. 
EXAMPLE 33 
Example 27 was repeated except that hexan-1-ol was used in place of 
propan-2-ol. 
EXAMPLE 34 
Example 27 was repeated except that heptan-1-ol was used in place of 
propan-2-ol. 
EXAMPLE 35 
Example 27 was repeated except that octan-1-ol was used in place of 
propan-2-ol. 
EXAMPLE 36 
Example 27 was repeated except that 3-methylbutan-1-ol was used in place of 
propan-2-ol. 
EXAMPLE 37 
Example 27 was repeated except that 3-methylpentan-1-ol was used in place 
of propan-2-ol. 
The results of Examples 27 to 37 are given in Table 4. 
EXAMPLE 38 
Example 27 was repeated except that diethylene glycol was used in place of 
propan-2-ol. Analysis of the product showed: 
______________________________________ 
wt % reaction mixture 
______________________________________ 
Unreacted glycol 
36 
Dioxan 31 
Ethylene glycol 9 
Triethylene glycol 
20 
Others 4 
______________________________________ 
TABLE 4 
__________________________________________________________________________ 
Weight % of reaction product 
Unreacted 
2,2 dialkyl 
1,1 dialkyl 
1,2 dialkyl 
Alkene 
Example 
Alkanol 
alkanol 
ether ether ether Alkenes 
dimers 
__________________________________________________________________________ 
27 Propan-2-ol 
46 48 -- -- 5* 1 
28 Butan-2-ol 
25 43 -- -- 28* 4 
29 Pentan-2-ol 
9 2 -- -- 82 3 
30 Hexan-2-ol 
8 4 -- -- 86 1 
31 Butan-1-ol 
27 -- 53 6 12* 1 
32 Pentan-1-ol 
40 -- 40 4 9 7 
33 Hexan-1-ol 
33 -- 48 4 12 3 
34 Heptan-1-ol 
31 -- 50 2 14 4 
35 Octan-1-ol 
43 -- 40 -- 13 4 
36 3-Methyl 
40 -- 45 -- 4 10 
butan-1-ol 
37 3-Methyl 
43 -- 31 -- 12 15 
pentan-1-ol 
__________________________________________________________________________ 
*Due to loss of gaseous alkenes on sampling these figures are much too 
small hence all others in the relevent lines are maxima. 
PRODUCTION OF AN ALCOHOL BY REACTING AN OLEFIN WITH WATER IN THE PRESENCE 
OF A HYDROGEN ION-EXCHANGED LAYERED CLAY 
EXAMPLE 39 
Hydrogen ion-exchanged bentonite (3.75 g) and water (40 g) were sealed in a 
100 ml stirred autoclave which was then charged with 40 ml liquid 
butene-1. The autoclave was heated to 200.degree. C. for 2.5 hours giving 
a maximum pressure of 65 bar. After cooling and venting 38.7 g of liquid 
product having the butan-2-ol content shown in Table 5 was obtained. 
EXAMPLE 40 
Example 39 was repeated except that ethyl carbitol (20 g) was added as 
solvent and the amount of water was reduced from 40 g to 20 g. The results 
are given in Table 5. 
TABLE 5 
______________________________________ 
Yield of butan-2-ol 
Conversion of but-1-ene 
in liquid product 
to butan-2-ol 
Example (g) (%) 
______________________________________ 
39 1.55 4.2 
40 2.24* 6.1 
______________________________________ 
*excluding ethyl carbitol solvent 
EXAMPLE 41 
Water (40 grams per hour) was passed over a bed containing hydrogen 
ion-exchanged bentonite (20 ml. mesh size 1.4 mm particles) mixed with 20 
ml inert diluent in a continuous flow high pressure apparatus charged to 
40 bar with ethylene and maintained at 40 bar with a slow ethylene bleed 
both in and out of the apparatus. At a reaction temperature of 280.degree. 
C., 0.5% weight of water was converted to ethanol and at 390.degree. C. 
0.3% weight of water was converted to ethanol. No other products were 
observed. 
THE PRODUCTION OF AN ALKYL AROMATIC COMPOUND BY REACTING AN AROMATIC 
HYDROCARBON WITH AN ALKYLATING AGENT 
EXAMPLE 42 
Into a 200 ml stirred stainless steel autoclave was placed benzene (120 g, 
1.52 mole) and hydrogen ion-exchanged bentonite (10 g). The autoclave was 
sealed and charged with liquid propylene (about 20 ml, 0.25 mole) then 
stirred (400 rpm) at 230.degree. C. for 2.5 hours. The maximum pressure 
obtained was 28 bar. After reaction, the autoclave was allowed to cool and 
any gaseous products were vented off. The liquid products and catalyst 
were removed to give liquid products (124 g) which contained cumene (19.7% 
by weight, made in a yield of approximately 81% from propylene) and 
diisopropyl benzenes (1.5% by weight, made in a yield of approximately 
4.5% from propylene) as major products. 
EXAMPLE 43 
Example 42 was repeated except that the amount of hydrogen ion-exchanged 
bentonite was reduced from 10 g to 2.5 g. The liquid products (126 g) 
contained cumene (20.9% by weight) and diisopropyl benzenes (1.5% by 
weight) made in a yield of approximately 88 and 4.5% from propylene 
respectively. 
EXAMPLE 44 
A solution of benzene and isopropylene (about 4:1 mole ratio) was fed over 
a hydrogen ion-exchanged bentonite catalyst (40 ml) in the reactor of a 
continuous plant at a rate of 20 ml to 90 ml per hour at a reaction 
temperature of 230.degree. C. and a pressure maintained at 30 bar. A 
typical analysis of the liquid products with a feed rate of 90 ml per hour 
showed 69% benzene, 26% cumene and 5% diisopropyl benzenes by weight. 
EXAMPLE45 
Into a 200 ml stirred stainless steel autoclave was placed toluene (70 g, 
0.76 mole) and hydrogen ion-exchanged bentonite (5 g). The autoclave was 
sealed and charged with ethylene to 40 bar. The autoclave was then stirred 
(400 rpm) at 200.degree. C. for 2.5 hours when a maximum pressure of 65 
bar was attained. On cooling and venting of any gaseous products, the 
liquid products and catalyst were removed. The liquid products (64 g) 
contained isomers of ethyl toluene (4.6% by weight) in the meta-ortho:para 
ratio of 1:1.6:1. 
EXAMPLE 46 
Phenol (9.4 g, 0.1 mole), hex-1-ene (8.4 g, 0.1 mole) and hydrogen 
ion-exchanged bentonite (1 g) were gently refluxed in a two-necked flask 
(50 ml) fitted with a condenser and a serum cap through which small 
samples of reaction product could be periodically removed by syringe. 
After 30 minutes reaction time, the reaction mixture contained unreacted 
phenol (6%), isomers of hexyl phenol (67%) and isomers of dihexyl phenol 
(26%).