Process for producing .alpha.,.beta.-unsaturated carboxylic acid esters

.alpha.,.beta.-Unsaturated carboxylic acid esters are produced by a catalytic reaction of .alpha.,.beta.-unsaturated carboxylic acids and/or .alpha.,.beta.-unsaturated carboxylic acid amides with aliphatic alcohols in the presence of a solid acid catalyst comprising zirconium oxide, titanium oxide or a composite oxide thereof containing phosphorus.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a process for producing an 
.alpha.,.beta.-unsaturated carboxylic acid ester, and more particularly, 
to a process for producing an .alpha.,.beta.-unsaturated carboxylic acid 
ester by reacting an .alpha.,.beta.-unsaturated carboxylic acid and/or an 
.alpha.,.beta.-unsaturated carboxylic acid amide with an aliphatic alcohol 
in the presence of a solid acid as a catalyst. 
An .alpha.,.beta.-unsaturated carboxylic acid ester is industrially very 
useful as a starting material for synthetic resins. In particular, methyl 
methacrylate is a starting material for poly(methyl methacrylate) which is 
excellent in weatherability and transparency. 
2. Description of the Related Art 
Heretofore, an .alpha.,.beta.-unsaturated carboxylic acid ester, for 
example, methyl methacrylate, has been produced by treating acetone 
cyanohydrin with concentrated sulfuric acid to form methacrylamide sulfate 
and esterifying it with methanol. 
This method has been used for the industrial production, but this process 
has various drawbacks such as corrosion of the apparatus material with the 
concentrated sulfuric acid and formation of a large amount of ammonium 
sulfate of a low value as a by-product. 
On the contrary, Japanese Patent Publication No. Sho 63-63537 (U.S. Pat. 
No. 4,464,539) discloses a process for producing an 
.alpha.,.beta.-unsaturated carboxylic acid ester from cyanohydrin without 
using sulfuric acid. 
According to this method, an .alpha.-hydroxycarboxylic acid amide produced 
by hydration of the cyanohydrin is brought into contact with a first step 
solid acid catalyst in the presence of water, and then the resulting 
reaction mixture containing an .alpha.,.beta.-unsaturated carboxylic acid 
and/or an .alpha.,.beta.-unsaturated carboxylic acid amide is brought into 
contact with a second step solid acid catalyst together with an aliphatic 
alcohol to produce an .alpha.,.beta.-unsaturated carboxylic acid ester. 
In this method, as representative solid acid catalysts, there are used a 
catalyst containing a phosphoric acid salt such as lanthanum phosphate, 
cerium phosphate and the like in the first step and a catalyst containing 
a phosphate or oxide of titanium or zirconium in the second step. 
As a result, an .alpha.,.beta.-unsaturated carboxylic acid ester can be 
produced in a 80-89 mole % yield without forming ethers as by-broducts by 
a dehydration reaction of the aliphatic alcohol. 
However, when an .alpha.,.beta.-unsaturated carboxylic acid ester is 
produced by the above-mentioned method, in addition to the end product, 
.alpha.,.beta.-unsaturated carboxylic acid ester, there are formed various 
by-products due to the action of the second step solid acid catalyst. 
The by-products include alkylamines produced by the dehydration reaction of 
ammonia formed in the first and the second steps with the starting 
material, aliphatic alcohol, and N-alkyl .alpha.,.beta.-unsaturated 
carboxylic acid amides produced by the dehydration reaction of the 
.alpha.,.beta.-unsaturated carboxylic acid and/or 
.alpha.,.beta.-unsaturated carboxylic acid amide formed in the first step 
with the above-mentioned alkylamines and/or aliphatic alcohol. 
The yield of the by-products such as alkylamines and N-alkyl 
.alpha.,.beta.-unsaturated carboxylic acid amides is about 2-9 mole % 
though it varies depending on the type of the second step solid acid 
catalyst, the reaction temperature and the like. 
The formation of such by-products not only makes complicated the separation 
and purification steps for the .alpha.,.beta.-unsaturated carboxylic acid 
ester and the recirculation step of unreacted .alpha.,.beta.-unsaturated 
carboxylic acid and the like, but makes lower the economical efficiency of 
the process itself for producing the .alpha.,.beta.-unsaturated carboxylic 
acid ester depending on the economical values and demands for the 
alkylamines and N-alkyl .alpha.,.beta.-unsaturated carboxylic acid amides. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a process for producing an 
.alpha.,.beta.-unsaturated carboxylic acid ester substantially free from 
the formation of by-products. 
Another object of the present invention is to provide a process for 
producing an .alpha.,.beta.-unsaturated carboxylic acid ester in good 
yield. 
According to the present invention, there is provided a process for 
producing an .alpha.,.beta.-unsaturated carboxylic acid ester which 
comprises a catalytic reaction of at least one member selected from the 
group consisting of .alpha.,.beta.-unsaturated carboxylic acids and 
.alpha.,.beta.-unsaturated carboxylic acid amides represented by the 
general formula (1), 
##STR1## 
where R.sub.1, R.sub.2 and R.sub.3 are independently selected from the 
group consisting of hydrogen and alkyl having 1-4 carbon atoms, and X is 
hydroxy or amino with an aliphatic alcohol in the presence of a solid acid 
catalyst, said solid acid catalyst being selected from the group 
consisting of zirconium oxide containing phosphorus, titanium oxide 
containing phosphorus, and a composite oxide of zirconium oxide and 
titanium oxide containing phosphorus, and the atomic ratio of phosphorus 
to zirconium and/or titanium being 0.0001-0.3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the present invention, there may be used an .alpha.,.beta.-unsaturated 
carboxylic acid and/or an .alpha.,.beta.-unsaturated carboxylic acid amide 
represented by the general formula (1), 
##STR2## 
where R.sub.1, R.sub.2 and R.sub.3 are independently selected from the 
group consisting of hydrogen and alkyl having 1-4 carbon atoms, and X is 
hydroxy or amino as one of the starting materials. 
Exemplary suitable .alpha.,.beta.-unsaturated carboxylic acids and amides 
include: 
acrylic acid, 
acrylamide, 
methacrylic acid, 
methacrylamide, 
.beta.-methylacrylic acid, 
.beta.-methylacrylamide, 
.alpha.,.beta.-dimethylacrylic acid, 
.alpha.,.beta.-dimethylacrylamide, 
.beta.,.beta.-dimethylacrylic acid, 
.beta.,.beta.-dimethylacrylamide, 
.beta.-ethylacrylic acid, and 
.beta.-ethylacrylamide. 
The .alpha.,.beta.-unsaturated carboxylic acid and/or 
.alpha.,.beta.-unsaturated carboxylic acid amide may be used separately 
from the other starting material, an aliphatic alcohol, or as a solution 
in the aliphatic alcohol or an aqueous aliphatic alcohol solution. 
In the present invention, the above-mentioned .alpha.,.beta.unsaturated 
carboxylic acid and/or .alpha.,.beta.-unsaturated carboxylic acid amide 
may be prepared by known methods such as those disclosed in Japanese 
Patent Publication No. Sho 63-10940 (U.S. Pat. No. 4,464,539) and Japanese 
Patent Publication No. Hei 3-13213. 
For example, according to the method of Japanese Patent Publication No. Sho 
63-10940 (U.S. Pat. No. 4,464,539), .alpha.-hydroxycarboxylic acid amide 
obtained by the hydration reaction of cyanohydrin is preferably brought 
into contact with a solid acid catalyst in the presence of water to give a 
reaction mixture containing an .alpha.,.beta.-unsaturated carboxylic acid 
and/or an .alpha.,.beta.-unsaturated carboxylic acid amide. 
As .alpha.-hydroxycarboxylic acid amides, there may be mentioned lactic 
amide, .alpha.-hydroxybutyramide, .alpha.-hydroxyisobutyramide, and 
.alpha.-hydroxyvaleramide, .alpha.-hydroxyisovaleramide, and 
.alpha.-methyl-.alpha.-hydroxybutyramide. 
As solid acid catalysts, there may be used catalysts containing phosphoric 
acid salts such as lanthanum phosphate and cerium phosphate. 
According to the method of Japanese Patent Publication No. Hei 3-13213, an 
aqueous solution of .alpha.-hydroxyisobutyramide obtained by hydration of 
acetone cyanohydrin is brought into contact with a solid acid catalyst to 
produce a reaction mixture containing methacrylic acid and methacrylamide. 
As a solid acid catalyst, there is used a catalyst containing a phosphoric 
acid salt such as magnesium primary phosphate or a sulfate such as cadmium 
sulfate. 
Exemplary suitable aliphatic alcohols as a starting material in the present 
invention include: 
methyl alcohol, 
ethyl alcohol, 
n-propyl alcohol, 
i-propyl alcohol, 
i-butyl alcohol, 
ethylene glycol, 
ethylene glycol monomethyl ether, 
propylene glycol monomethyl ether, 
and the like, 
and substituted aliphatic alcohols. 
An appropriate aliphatic alcohol may be selected from these alcohols 
depending on the type of the end product. 
As solid acid catalysts of the present invention, there may be used such 
catalyst producible by dispersing properly phosphorus in zirconium oxide, 
titanium oxide or a composite oxide of zirconium oxide and titanium oxide. 
In these oxides or composite oxide, the atomic ratio of phosphorus 
(designated as "P") to zirconium and/or titanium (designated as "M"), that 
is, (P/M) is 0.0001-0.3, preferably 0.001-0.2 though it varies depending 
on the specific surface area (m.sup.2 /g) of the oxide or composite oxide. 
When the atomic ratio (P/M) is less than 0.0001, the yield of the end 
product, .alpha.,.beta.-unsaturated carboxylic acid ester is markedly 
lowered. When the atomic ratio exceeds 0.3, the yield of by-products such 
as alkylamines and N-alkyl .alpha.,.beta.-unsaturated carboxylic acid 
amides disadvantageously increases. 
As phosphorus components, there may be mentioned: phosphoric acid, 
ammonium dihydrogen phosphate, 
diammonium hydrogen phosphate, 
triammonium phosphate; 
phosphoric acid esters such as 
trimethyl phosphate, 
triethyl phosphate, 
tributyl phosphate, 
triphenyl phosphate, 
and the like; 
phosphorus hydride, 
phosphorus bromide, 
phosphorus chloride, 
phosphorus oxychloride, 
and the like. 
Among them, from the standpoint of easy handling, there is preferably 
mentioned: 
phosphoric acid, 
ammonium dihydrogen phosphate, 
diammonium hydrogen phosphate, 
triammonium phosphate, 
trimethyl phosphate, and 
triethyl phosphate. 
In the following preparation of the catalyst, seemingly these phosphorus 
compounds react with hydroxide or oxide of zirconium and/or titanium and 
are partly fixed to the surface as phosphoric acid, zirconium phosphate 
and/or titanium phosphate, which are then calcined. As a result, these 
become stable active points. 
In the present invention, zirconium oxide containing phosphorus can be 
prepared from the above-mentioned phosphorus compound, zirconium hydroxide 
and/or zirconium oxide by using a known catalyst preparation method such 
as a kneading method, a soaking method, a chemical vapor deposition or the 
like. 
Alternatively, a co-precipitation method or kneading method is used to 
prepare zirconium hydroxide and/or zirconium oxide carried on a carrier 
such as silica, alumina, silica-alumina and the like and then a soaking 
method, chemical vapor deposition method or the like is employed to 
combine a phosphorus compound with said zirconium compound carried on a 
carrier. 
In addition, a titanium oxide or a composite oxide of titanium oxide and 
zirconium oxide containing phosphorus can be prepared by a method similar 
to that as above using the above-mentioned phosphorus compound and 
titanium hydroxide and/or titanium oxide, or a mixture of titanium 
hydroxide and/or titanium oxide and zirconium hydroxide and/or zirconium 
oxide. 
The amount of the starting material in the present invention is not 
particularly critical. For example, when the starting material is 
.alpha.-hydroxycarboxylic acid amide, the amount of water is usually 0-200 
moles, preferably 1-50 moles per 1 mole of .alpha.-hydroxycarboxylic acid 
amide. 
The amount of aliphatic alcohol is usually 1-200 moles, preferably 1-50 
moles per 1 mole of the resulting .alpha.,.beta.-unsaturated carboxylic 
acid and/or .alpha.,.beta.-unsaturated carboxylic acid amide contained in 
the reaction mixture. 
In the present invention, the reaction may be carried out in a vapor phase 
or liquid phase as far as the starting materials can be brought into 
contact with the solid acid catalyst, and a vapor phase or a vapor-liquid 
mixed phase is preferable. 
The reaction may be carried out by a fixed bed system, a fluidized bed 
system or any other optional system. 
The reaction temperature is usually 150-500.degree. C., preferably 
200-450.degree. C. 
The reaction pressure is usually atmospheric pressure, but may be higher or 
lower than atmospheric pressure. 
Feeding speeds of the starting materials, i.e. .alpha.,.beta.-unsaturated 
carboxylic acid and/or .alpha.,.beta.-unsaturated carboxylic acid amide 
and aliphatic alcohol may be varied widely depending on type of catalyst, 
reaction temperature and the like, but usually a liquid hourly space 
velocity (LHSV) in the range of 0.005-10 hr.sup.-1 is sufficient. 
Further, in carrying out the reaction, the starting material may be mixed 
with an inert gas such as a nitrogen gas and then brought into contact 
with the catalyst layer. 
The catalyst may be subjected to a pre-treatment by feeding ammonia or 
aqueous ammonia to the catalyst layer and then the reaction may be started 
though such pretreatment is not always necessary. 
According to the present invention, an .alpha.,.beta.-unsaturated 
carboxylic acid ester can be obtained in good yield while suppressing the 
formation of by-products such as alkylamines and N-alkyl 
.alpha.,.beta.-unsaturated carboxylic acid amides as far as possible, or 
substantially completely, for a long period of time in the process for 
producing an .alpha.,.beta.-unsaturated carboxylic acid ester starting 
from an .alpha.,.beta.-unsaturated carboxylic acid and/or an 
.alpha.,.beta.-unsaturated carboxylic acid amide. 
For example, an .alpha.,.beta.-unsaturated carboxylic acid ester can be 
produced in a 72-94 mole % for more than 10 days substantially without 
forming by-products such as the amines and amides. 
In the following, the present invention is explained referring to examples 
and comparative examples. 
In all of the examples and comparative examples, there was used a reaction 
tube 9 having two steps of catalyst layers in FIG. 1. 
The first step catalyst layer 5 was packed with a LaPO.sub.4 catalyst 
prepared as shown below in the procedures of Examples 1-16, Examples 
28-39, Comparative Examples 1-9 and Comparative Examples 14-20, and with 
melted alumina balls in place of catalyst in Examples 17-27 and 
Comparative Examples 10-13. 
In the following, "%" is by weight unless otherwise specified. 
PREATION OF THE FIRST STEP CATALYST 
Lanthanum oxide (La.sub.2 O.sub.3) 21.2 g (0.065 mole) was completely 
dissolved in an aqueous solution of nitric acid, heated and concentrated 
to form lanthanum nitrate. 
Water was added thereto to form a 400 ml of an aqueous solution of 
lanthanum nitrate. 
Then, to said aqueous solution of lanthanum nitrate was added 100 ml of an 
aqueous solution containing disodium hydrogenphosphate (Na.sub.2 
HPO.sub.4) 20.3 g (0.143 mole) and a white precipitate was formed. The 
resulting solution was stirred at 80.degree. C. for one hour, and the 
white precipitate was sufficiently washed with water by decantation 
method, separated by filtration and then washed with water. 
The resulting white precipitate was dried at 120.degree. C., calcined in an 
air stream at 400.degree. C. for 6 hours, and molded into particles of 
10-16 mesh to prepare a lanthanum phosphate (LaPO.sub.4) catalyst. 
The indication "lanthanum phosphate (LaPO.sub.4)" does not always show the 
structure of the phosphoric acid salt contained in the catalyst, but the 
atomic ratio of lanthanum to phosphorus in the phosphoric acid salt. 
EXAMPLE 1 
The second step catalyst was prepared as shown below. Zirconium oxychloride 
(ZrOCl.sub.2.8H.sub.2 O) 36.1 g (0.112 mole) was dissolved in water 50 ml 
and then added with stirring to a solution formed by dissolving sodium 
hydroxide (NaOH) 9.84 g (0.246 mole) in water 200 ml and heated to 
80.degree. C. to form white precipitate. 
After stirring the resulting solution for one hour, the white precipitate 
was sufficiently washed with water by a decantation method, filtered, 
further washed with water and dried at 100.degree. C. to obtain zirconium 
hydroxide (Zr(OH).sub.4) 16.9 g. Then the resulting zirconium hydroxide 
15.9 g (0.100 mole) was ground for 3 hours by an automatic mortar. To the 
zirconium hydroxide thus ground was added diammonium hydrogenphosphate 
((NH.sub.4).sub.2 HPO.sub.4) 0.46 g (0.0035 mole) finely divided by an 
agate mortar, ground and mixed for 10 hours. 
The resulting mixture was allowed to stand in air at 200.degree. C. for 5 
hours, then calcined in air at 400.degree. C. for 6 hours, and molded into 
particles of 10-16 mesh to prepare zirconium oxide containing phosphorus 
of P/Zr=0.035 (hereinafter referred to as "P-ZrO.sub.2 "). 
In a Pyrex reaction tube 9 of 12 mm in inner diameter as shown in FIG. 1, a 
second step catalyst layer 6 was composed of 5 ml of the above-mentioned 
P-ZrO.sub.2 catalyst, a first step catalyst layer 5 was composed of 5 ml 
of the above-mentioned LaPO.sub.4 catalyst, and a vaporization portion 4 
was packed with melted alumina balls of 3 mm in diameter. 
This reaction tube was fixed to an electric furnace capable of controlling 
independently the temperature of the first step catalyst layer and the 
temperature of the second step catalyst layer, and was connected with a 
reaction fluid receiver 7 cooled with dry ice trap 8 as illustrated in 
FIG. 1. 
Then, a nitrogen gas was introduced from a carrier gas feeding pipe 3 at 
the top portion of the reaction tube and fed at a rate of 10 ml/min (GHSV 
120 hr.sup.-1) to the catalyst layer, while the catalyst layer temperature 
was raised to 275.degree. C. at the first step and 330.degree. C. at the 
second step. 
Methyl alcohol was fed at a rate of 8.5 ml/hr (LHSV 1.7 hr.sup.-1) through 
a starting material feeding pipe 2 while a 36% aqueous solution of 
.alpha.-hydroxyisobutyramide was fed at a rate of 4.4 ml/hr (LHSV 0.88 
hr.sup.-1) through a starting material feeding pipe 1. 
During 3-4 hours after beginning the feed of starting materials, reaction 
fluid fraction for this one hour was captured by means of dry ice trap 8 
and analyzed by gas chromatography. The yield of methyl methacrylate 
(hereinafter referred to as "MMA") based on the starting material, 
.alpha.-hydroxyisobutyramide, was 91.5 mole %. 
Other than MMA, only acetone was formed as a by-product in a 3.5 mole % 
yield based on .alpha.-hydroxyisobutyramide, but methylamine, 
dimethylamine, trimethylamine, N-methylmethacrylamide and 
N,N-dimethylmethacrylamide were not detected. 
EXAMPLES 2-12 AND COMATIVE EXAMPLES 1-6 
The procedure of Example 1 was repeated except that the atomic ratio (P/Zr) 
of phosphorus to zirconium in P-ZrO.sub.2 as the second step catalyst and 
the reaction temperature at the second step were changed. The P/Zr, 
reaction temperatures and yields of reaction products are shown in Table 
1. 
COMATIVE EXAMPLES 7 AND 8 
The procedure of Example 1 was repeated except that the other second step 
catalyst species was used and the reaction temperature of the second step 
was changed. The other second step catalyst was prepared as shown below. 
Zirconium oxychloride (ZrOCl.sub.2.8H.sub.2 O) 36.1 g (0.112 mole) was 
dissolved in 50 ml of water, and to the resulting solution was added 200 
ml of an aqueous solution containing disodium hydrogenphosphate (Na.sub.2 
HPO.sub.4) 31.8 g (0.224 mole) to form a white precipitate. The resulting 
mixture was stirred at 80.degree. C. for one hour, and the white 
precipitate was sufficiently washed with water by a decantation method, 
filtered, further washed with water, and dried at 120.degree. C. to obtain 
zirconium phosphate (Zr(HPO.sub.4).sub.2) 30.1 g. 
The resulting zirconium phosphate was calcined at 500.degree. C. for 6 
hours in air, and molded into particles of 10-16 mesh to form a zirconium 
phosphate (Zr(HPO.sub.4).sub.2) of P/Zr=2.00. 
The indication "zirconium phosphate (Zr(HPO.sub.4))" does not always show 
the structure of the phosphoric acid salt contained in the catalyst, but 
the atomic ratio of zirconium to phosphorus in the phosphoric acid salt. 
Table 1 shows the P/Zr, reaction temperatures and yields of reaction 
products. 
EXAMPLE 13 
The procedure of Example 1 was repeated except that the other second step 
catalyst species was used. 
The other second step catalyst was prepared as shown below. 
Zirconium oxychloride (ZrOCl.sub.2.8H.sub.2 O) 36.1 g (0.112 mole) was 
dissolved in 50 ml of water. The resulting solution was added with 
stirring to a solution prepared by dissolving sodium hydroxide (NaOH) 9.84 
g (0.246 mole) in 200 ml of water and heating to 80.degree. C. to produce 
white precipitate. 
After stirring for one hour, the white precipitate was sufficiently washed 
with water by a decantation method, filtered, washed with water again and 
dried at 100.degree. C. The product thus dried was calcined in air at 
330.degree. C. for 4 hours to obtain zirconium oxide (ZrO.sub.2) 13.0 g. 
The resulting zirconium oxide 10.0 g (0.081 mole) was added to 50 ml of an 
aqueous solution containing trimethyl phosphate ((CH.sub.3 O).sub.3 
PO.sub.4) 3.5 g (0.025 mole) and soaked at 80.degree. C. for 6 hours. 
Then, the product was washed with water, filtered, dried at 100.degree. 
C., and calcined in air at 400.degree. C. for 6 hours to prepare a 
zirconium oxide (P-ZrO.sub.2) catalyst containing phosphorus of 
P/Zr=0.035. The phosphorus content in zirconium oxide was determined by a 
fluorescent X-ray method. 
Table 2 shows the yields of reaction products. 
EXAMPLE 14 
The procedure of Example 1 was repeated except that the other second step 
catalyst species was used. 
The other second step catalyst was prepared as shown below. 
Zirconium oxychloride (ZrOCl.sub.2.8H.sub.2 O) 36.1 g (0.112 mole) was 
dissolved in 50 ml of water, and the resulting solution was added with 
stirring to a solution prepared by dissolving sodium hydroxide (NaOH) 9.84 
g (0.246 mole) in 200 ml of water and heating to 80.degree. C. to form a 
white precipitate. 
After stirring for one hour, the resulting white precipitate was 
sufficiently washed with water by a decantation method, filtered, washed 
with water again and dried at 100.degree. C. 
The product thus dried was calcined in air at 330.degree. C. for 4 hours to 
obtain zirconium oxide (ZrO.sub.2) 13 g. 
Then the resulting zirconium oxide 10.0 g (0.081 mole) was added to 50 ml 
of an aqueous solution containing 85% phosphoric acid 0.58 g (0.005 mole) 
and soaked at room temperature for 120 hours. The resulting product was 
washed with water, filtered, dried at 100.degree. C. and calcined in air 
at 400.degree. C. for 6 hours to obtain a P-ZrO.sub.2 catalyst of 
P/Zr=0.035. 
The phosphorus content in the resulting zirconium oxide was determined by a 
fluorescent X-ray method. 
Table 2 shows the yields of the reaction product. 
EXAMPLE 15 
The procedure of Example 1 was repeated except that the other second step 
catalyst species was used. 
The other second step catalyst was prepared as shown below. 
Zirconium oxychloride (ZrOCl.sub.2.8H.sub.2 O) 36.1 g (0.112 mole) was 
dissolved in 50 ml of water, and the resulting solution was added with 
stirring to a solution prepared by dissolving sodium hydroxide (NaOH) 9.84 
g (0.246 mole) in 200 ml of water and heating to 80.degree. C. to form a 
white precipitate. 
After stirring for one hour , the white precipitate was sufficiently washed 
with water by a decantation method, filtered, washed with water again, and 
dried at 100.degree. C. The product thus dried was calcined in air at 
330.degree. C. for 4 hours to obtain zirconium oxide (ZrO.sub.2) 13.0 g. 
Then the resulting zirconium oxide 10.0 g (0.081 mole) was added to 50 ml 
of an aqueous solution containing diammonium hydrogenphosphate 
((NH.sub.4).sub.2 HPO.sub.4) 1.3 g and soaked at room temperature for 72 
hours. The resulting product was washed with water, filtered, and dried at 
100.degree. C., calcined in air at 400.degree. C. for 6 hours to prepare a 
P-ZrO.sub.2 catalyst of P/Zr=0.035. 
The phosphorus content in zirconium oxide was determined by a fluorescent 
X-ray method. 
Table 2 shows the yield of reaction products. 
EXAMPLE 16 
The procedure of Example 1 was repeated except that the other second step 
catalyst species was used. 
Said second step catalyst was prepared as shown below. 
Zirconium oxychloride (ZrOCl.sub.2.8H.sub.2 O) 7.9 g (0.024 mole) was 
dissolved in 30 ml of water, and the resulting solution was added to 7.0 g 
of silica (SILICA 951W, trade name, supplied by Fuji Davison Co.) treated 
at 1000.degree. C. for 5 hours. The resulting mixture was vaporized to 
driness and calcined in air at 400.degree. C. for 3 hours to obtain a 
silica carrying 3% zirconium oxide. 
The resulting silica carrying zirconium oxide 9.0 g (corresponding to 
0.0022 mole of ZrO.sub.2) was added to 50 ml of an aqueous solution 
containing trimethyl phosphate ((CH.sub.3 O ).sub.3 PO.sub.4) 0.5 g 
(0.0036 mole) and soaked at 80.degree. C. for 6 hours. Then, the product 
was washed with water, filtered, dried at 100.degree. C., and calcined in 
air at 400.degree. C. for 6 hours to obtain a silica catalyst carrying 
zirconium oxide containing phosphorus of P/Zr=0.035. 
The phosphorus content in zirconium oxide was determined by a fluorescent 
X-ray method. 
Table 2 shows the yield of the reaction product. 
COMATIVE EXAMPLE 9 
The procedure of Example 1 was repeated except that the other second step 
catalyst species was used. 
Said second step catalyst was prepared as shown below. 
The zirconium phosphate (Zr(HPO.sub.4).sub.2) catalyst of P/Zr=2.00 
obtained in Comparative Example 7, 0.41 g (0.0014 mole) was finely divided 
by using an agate mortar. 
On the other hand, zirconium oxide (ZrO.sub.2) obtained in Example 13, 10.0 
g (0.081 mole) was ground by an automatic mortar for 3 hours. To the 
zirconium oxide thus ground was added the above-mentioned finely divided 
zirconium phosphate and ground and mixed for 10 hours. 
The resulting mixture was calcined in air at 400.degree. C. for 6 hours and 
molded into particles of 10-16 mesh to prepare a P-ZrO.sub.2 catalyst of 
P/Zr=0.035. 
The phosphorus content in the zirconium oxide was measured by a fluorescent 
X-ray method. 
Table 2 shows the yield of the reaction product. 
EXAMPLE 17 
The procedure of Example 1 was repeated except that the first step catalyst 
layer portion 5 was packed with melted alumina balls of 3 mm in diameter 
in place of the catalyst, the second step catalyst layer 6 was packed with 
a P-ZrO.sub.2 catalyst (P/Zr=0.035) obtained in Example 13, and the 
starting materials and amounts thereof were changed as shown below. 
In place of a 36% aqueous solution of .alpha.-hydroxyisobutyramide and 
methyl alcohol, there was used a 20% solution of methacrylamide in methyl 
alcohol as starting materials, and this solution was fed through starting 
material feeding pipe 1 at a rate of 3.4 ml/hr (LHSV 0.68 hr.sup.-1) while 
nothing was fed through starting material feeding pipe 2. 
Table 3 shows the yield of the reaction product. 
EXAMPLES 18-21 
The procedure of Example 17 was repeated except that the starting material 
and concentration thereof were changed. Table 3 shows the starting 
materials, concentrations thereof and yields of the reaction products. 
EXAMPLE 22 
The procedure of Example 1 was repeated except that the first step catalyst 
layer 5 was packed with melted alumina balls of 3 mm in diameter in place 
of the catalyst and the starting materials, the amounts fed and the 
reaction time were changed as shown below. 
As starting material, a 20% solution of methacrylamide in methyl alcohol 
was used in place of a 36% aqueous solution of 
.alpha.-hydroxyisobutyramide and methyl alcohol and fed through starting 
material feeding pipe 1 at a rate of 3.4 ml/hr (LHSV 0.68 hr.sup.-1) while 
nothing was fed through starting material feeding pipe 2. During 3-4 hours 
and 240-241 hours after beginning to feed the starting material, the 
reaction fluid fraction corresponding to respective one hour was captured 
by dry ice trap 8 and analyzed by gas chromatography. 
Table 4 shows the yield of the main reaction product (MMA) and productivity 
of the catalyst. 
EXAMPLES 23-27 AND COMATIVE EXAMPLES 10-13 
The procedure of Example 22 was repeated except that the atomic ratio of 
phosphorus to zirconium (P/Zr) of P-ZrO.sub.2 as the second step catalyst 
was changed. Table 4 shows P/Zr, yield of the main reaction product (MMA) 
and productivity of catalyst. 
EXAMPLE 28 
The procedure of Example 1 was repeated except that P-TiO.sub.2 was used in 
place of P-ZrO.sub.2 as a second step catalyst species. 
The second step catalyst was prepared as shown below. 
Titanium chloride (TiCl.sub.4) 40.1 g (0.211 mole) was dropwise added to 
and dissolved in 80 ml of ice-cooled water, and water was added thereto. 
To the resulting aqueous solution was gradually dropwise added a 28% 
aqueous ammonia until the aqueous solution became pH 7, followed by 
stirring at 80.degree. C. for one hour. 
The resulting precipitate was sufficiently washed with water by a 
decantation method, filtered, washed with water again, and dried at 
100.degree. C. to obtain 20.2 g of titanium hydroxide (Ti(OH).sub.4). 
The resulting titanium hydroxide 11.6 g (0.100 mole) was ground with an 
automatic mortar for 3 hours. To the titanium hydroxide thus ground was 
added diammonium hydrogenphosphate ((NH.sub.4).sub.2 HPO.sub.4) finely 
divided by using an agate mortar, 0.46 g (0.0035 mole), ground and mixed 
for 10 hours. 
The resulting mixture was allowed to stand in air at 200.degree. C. for 2 
hours, calcined in air at 400.degree. C. for 6 hours, and molded into 
particles of 10-16 mesh to produce a catalyst of titanium oxide containing 
phosphorus (hereinafter referred to as "P-TiO.sub.2 ") at a ratio of 
P/Ti=0.035. 
Table 5 shows P/Ti, reaction temperature and yield of reaction products. 
EXAMPLES 29-32 AND COMATIVE EXAMPLES 14-17 
The procedure of Example 28 was repeated except that the atomic ratio of 
phosphorus to titanium of P-TiO.sub.2 as a second step catalyst and the 
second step reaction temperature were changed. 
Table 5 shows each P/Ti, reaction temperature and yield of reaction 
product. 
EXAMPLE 33 
The procedure of Example 1 was repeated except that the second step 
catalyst species, P-ZrO.sub.2, was replaced with P-ZrTiO.sub.2. 
The second step catalyst, P-ZrTiO.sub.2, was prepared as shown below. 
Zirconium hydroxide (Zr(OH).sub.4) obtained in Example 1, 12.7 g (0.080 
mole) and titanium hydroxide (Ti(OH).sub.4) obtained in Example 28, 1.6 g 
(0.020 mole), were ground for 3 hours by an automatic mortar. 
To the mixture thus ground was added diammonium hydrogenphosphate 
((NH.sub.4).sub.2 HPO.sub.4) finely divided by an agate mortar, 0.46 g 
(0.0035 mole), ground and mixed for 10 hours. 
The resulting mixture was allowed to stand in air at 200.degree. C. for 5 
hours, calcined in air at 400.degree. C. for 6 hours and molded into 
particles of 10-16 mesh to obtain a composite oxide catalyst containing 
phosphorus (hereinafter referred to as "P-ZrTiO.sub.2 ") of P/(Zr+Ti) 
=0.035 and Zr/Ti=4.0. 
Table 6 shows P/(Zr+Ti), Zr/Ti, reaction temperature, and yield of reaction 
product. 
EXAMPLES 34-39 AND COMATIVE EXAMPLES 18-22 
The procedure of Example 33 was repeated except that P/(Zr+Ti), Zr/Ti of 
P-ZrTiO.sub.2, a second step catalyst, and the second step reaction 
temperature were changed. 
Table 6 shows P/(Zr+Ti), Zr/Ti, reaction temperature, and yield of reaction 
product. 
TABLE 1 
______________________________________ 
Second step 
catalyst layer 
Tempe- Yield (mol %) 
P/Zr of 
rature Amines 
Amides 
P--ZrO.sub.2 
(.degree.C.) 
MMA (*1) (*2) 
______________________________________ 
Example 1 0.0350 330 91.5 0.0 0.0 
Example 2 0.0007 300 83.2 0.0 0.0 
Example 3 0.0007 330 87.5 0.0 0.0 
Example 4 0.0070 300 88.5 0.0 0.0 
Example 5 0.0070 330 93.8 0.0 0.0 
Example 6 0.0140 300 91.2 0.0 0.0 
Example 7 0.0140 330 93.5 0.0 0.0 
Example 8 0.0350 300 91.3 0.0 0.0 
Example 9 0.140 300 93.5 0.0 0.0 
Example 10 
0.140 330 91.1 0.2 0.2 
Example 11 
0.250 300 94.0 0.3 0.2 
Example 12 
0.250 330 90.3 1.9 1.7 
Comparative 
0.0000 300 65.4 0.0 0.0 
Example 1 
Comparative 
0.0000 350 80.0 0.0 0.0 
Example 2 
Comparative 
0.350 300 90.8 3.5 3.2 
Example 3 
Comparative 
0.350 330 85.7 7.2 6.9 
Example 4 
Comparative 
0.400 300 90.5 4.0 3.3 
Example 5 
Comparative 
0.400 330 83.4 8.8 7.9 
Example 6 
Comparative 
2.00 280 89.0 3.2 2.0 
Example 7 
Comparative 
2.00 300 83.5 5.2 7.3 
Example 8 
______________________________________ 
(*1) Although methylamine, dimethylamine and trimethylamine are not 
directly produced from hydroxyisobutyramide, it is assumed for convenienc 
that the total amount of these products per the feed amount of 
hydroxyisobutyramide is the yield of amines (mol %). 
(*2) The yield of amides (mol %) is defined as the total amount of 
produced Nmethylmethacrylamide and N,Ndimethylmethacrylamide per the feed 
amount of hydroxyisobutyramide. 
TABLE 2 
__________________________________________________________________________ 
Preparation of second 
step catalyst Yield (mol %) 
Phosphorus 
Zirconium Amines 
Amides 
compound 
compound 
Carrier 
MMA (*1) 
(*2) 
__________________________________________________________________________ 
Example 1 
Diammonium 
Hydroxide 
None 
91.5 
0.0 0.0 
hydrogen- 
phosphate 
Example 13 
Trimethyl 
Oxide None 
94.4 
0.0 0.0 
phosphate 
Example 14 
Phosphoric 
Oxide None 
93.5 
0.0 0.0 
acid 
Example 15 
Diammonium 
Oxide None 
93.9 
0.0 0.0 
hydrogen- 
phosphate 
Example 16 
Trimethyl 
Oxide Silica 
92.1 
0.1 0.1 
phosphate 
Comparative 
Zirconium 
Oxide None 
71.3 
3.4 2.7 
Example 9 
phosphate 
__________________________________________________________________________ 
TABLE 3 
__________________________________________________________________________ 
Starting material 
Concent- Yield (mol %) 
ration 
Main Amines 
Amides 
Type % mol % 
product 
Ester 
(*3) 
(*4) 
__________________________________________________________________________ 
Example 17 
Methacrylamide 
20 
8.6 MMA 96.3 
0.0 0.0 
Methyl alcohol 
80 
91.4 
Example 18 
Methacrylic 
15 
5.9 
acid 
Methacrylamide 
5 
2.6 MMA 96.9 
0.0 0.0 
Methyl alcohol 
80 
91.5 
Example 19 
Methacrylic 
5 
1.7 
acid 
Methacrylamide 
15 
6.8 MMA 96.5 
0.0 0.0 
Methyl alcohol 
80 
91.5 
Example 20 
Methacrylamide 
15 
8.7 Ethyl 91.4 
0.0 0.0 
Ethyl alcohol 
85 
91.3 
methacry- 
late 
Example 21 
Methacrylamide 
10 
3.5 Ethylene 
Ethylene gly- 
45 
21.8 
glycol 
72.0 
0.0 0.0 
col monometh- 
Water 45 
74.7 
acrylate 
__________________________________________________________________________ 
(*3) Although alkylamines corresponding to aliphatic alcohols are not 
directly produced from methacrylic acid and/or methacrylamide, it is 
assumed for convenience that the total amount of these products per the 
feed amount of methacrylic acid and/or methacrylamide is the yield of 
amines (mol %). 
(*4) The yield of amides (mol %) is defined as the total amount of 
produced Nalkylmethacrylamide and N,Ndialkylmethacrylamide corresponding 
to aliphatic alcohols per the feed amount of methacrylic acid and/or 
methacrylamide. 
TABLE 4 
__________________________________________________________________________ 
Second step cata- Productivity 
lyst layer MMA Yield 
of catalyst 
Tempera- 
(mol %) (*6) 
P/Zr of 
ture 3-4 
240-241 Amides 
P--ZrO.sub.2 
(.degree.C.) 
hrs 
hrs MMA (*5) 
__________________________________________________________________________ 
Example 1 
0.0350 
330 91.5 
-- -- -- 
Example 22 
0.0350 
330 92.2 
79.4 26.5 
0.0 
Example 23 
0.0007 
330 89.1 
71.6 24.8 
0.0 
Example 24 
0.0070 
330 94.0 
78.8 26.7 
0.0 
Example 25 
0.0140 
330 94.3 
79.2 26.8 
0.0 
Example 26 
0.140 
330 93.8 
77.3 26.4 
0.1 
Example 27 
0.250 
330 93.1 
78.2 26.4 
0.6 
Comparative 
0.0000 
330 77.8 
42.3 18.5 
0.0 
Example 10 
Comparative 
0.350 
330 91.3 
71.8 25.2 
1.9 
Example 11 
Comparative 
0.400 
330 91.1 
67.5 24.5 
2.8 
Example 12 
Comparative 
2.00 330 84.4 
35.4 18.5 
3.4 
Example 13 
__________________________________________________________________________ 
(*5) The total product amount is calculated assuming that the yield of 
amides of *2 is the yield of Nmethylmethacrylamide. 
(*6) The total amount of MMA or amides per unit amount of catalyst after 
241 hours. 
TABLE 5 
______________________________________ 
Second step cata- 
lyst layer Yield (mol %) 
P/Ti of 
Tempera- Amines 
Amides 
P--TiO.sub.2 
ture (.degree.C.) 
MMA (*1) (*2) 
______________________________________ 
Example 28 
0.0350 330 91.5 0.0 0.0 
Example 29 
0.0007 330 86.5 0.0 0.0 
Example 30 
0.0070 330 92.8 0.0 0.0 
Example 31 
0.0140 300 94.2 0.0 0.0 
Example 32 
0.140 300 92.5 0.2 0.1 
Comparative 
0.0000 350 81.3 0.0 0.0 
Example 14 
Comparative 
0.350 300 87.8 4.5 3.5 
Example 15 
Comparative 
0.400 300 86.3 7.8 6.3 
Example 16 
Comparative 
0.500 300 82.3 8.2 7.1 
Example 17 
______________________________________ 
TABLE 6 
__________________________________________________________________________ 
Second step catalyst layer 
Yield (mol %) 
P/(Zr+Ti) Tempera- Amines 
Amides 
of P--ZrTiO.sub.2 
Zr/Ti 
ture (.degree.C.) 
MMA (*1) 
(*2) 
__________________________________________________________________________ 
Example 33 
0.0350 4.0 330 91.7 
0.0 0.0 
Example 34 
0.0350 0.5 330 92.5 
0.0 0.0 
Example 35 
0.0350 1.0 330 92.8 
0.0 0.0 
Example 36 
0.0350 2.0 300 92.2 
0.0 0.0 
Example 37 
0.0350 3.0 330 91.8 
0.0 0.0 
Example 38 
0.0070 4.0 300 85.2 
0.0 0.0 
Example 39 
0.0140 4.0 300 93.5 
0.1 0.1 
Comparative 
0.0000 1.0 350 84.0 
0.0 0.0 
Example 18 
Comparative 
0.0000 4.0 350 82.8 
0.0 0.0 
Example 19 
Comparative 
0.350 1.0 300 88.5 
6.7 4.5 
Example 20 
Comparative 
0.350 4.0 330 89.1 
4.2 3.8 
Example 21 
Comparative 
0.400 4.0 300 87.7 
5.6 4.7 
Example 22 
__________________________________________________________________________