201031463 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種製造二甲醚用觸媒，係用於使甲醇 進行脫水反應，而製造二甲醚。 【先前技術】 就二甲醚[CH3OCH3]的製造方法而言，已知有在觸媒 Ο 的存在下，使甲醇[CH3OH]進行脫水反應的方法，此觸媒 一般而言，可使用像是氧化鋁這樣的固體酸觸媒。 目前有各種使用含有二氧化矽或矽元素與氧化鋁的觸 媒，而合成二甲醚的方法正被檢討著。在專利文獻1之中 ’報告出如果使用含有1〜20重量％之二氧化矽與80〜99 重量％之氧化鋁的鋁矽酸鹽作爲觸媒，則碳往觸媒上面析 出的情形會受到抑制，因此甲醇的脫水反應之選擇性提升 。在專利文獻2之中，報告出如果使用Si含量爲0.1〜10 ® 質量％，Na含量爲0.1質量％以下的觸媒，可以較高反應 率並且選擇性良好地合成出二甲醚。在專利文獻3之中， 報告出如果使用由作爲主成分的氧化鋁；锆、二氧化矽、 及二氧化鈦之中至少1種所構成之合成觸媒，則在二甲醚 之合成中，反應率及選擇性能夠得以提升。 —般而言，在高溫水蒸氣環境氣氛下醚的合成，如果 使用不含矽的氧化鋁觸媒，則觸媒的脫水特性急劇降低。 相對於此，在專利文獻4之中，報告出藉由與矽化合物的 反應使表面變性的活性氧化鋁所構成之觸媒，如果使用此 -5- 201031463 觸媒，則在高溫水蒸氣環境氣氛進行醚類合成的情況，仍 然可維持觸媒的脫水特性。 [專利文獻1]特開昭59-42333號公報 [專利文獻2]特開2006-212557號公報 [專利文獻3]特開2003-73 32〇號公報 [專利文獻4]特開昭5 1-76207公報 【發明內容】 [發明所欲解決之課題] 然而，使用專利文獻1〜4所記載之任一觸媒進行甲 醇的脫水反應的情況中，在反應開始時（初期）皆可得到 高反應率，然而，如果反應長時間持續下去，則無法維持 充分的反應率。 本發明係提供一種經過長時間仍然能以高反應率使甲 醇進行脫水反應的製造二甲醚用觸媒，與使用該觸媒之二 甲醚的製造方法。 [用於解決課題之方法] 本發明的製造二甲醚用觸媒’係含有作爲主成分的氧 化鋁、與二氧化矽、以及鎂元素。 在本發明之觸媒中，換算爲Si02之二氧化矽含量， 係以相對於換算爲Al2〇3之氧化鋁含量100重量份而言爲 0.01〜1.2重量份者爲佳。 在本發明之觸媒中，換算爲Mg之鎂元素含量，係以 201031463 相對於換算爲Al2〇3之氧化鋁含量100重量份而言爲0.01 〜1.2重量份者爲佳。 本發明之二甲醚的製造方法，在本發明之製造二甲醚 用觸媒的存在下，使甲醇進行脫水反應。 [發明之效果] 依據本發明，經過長時間仍然能以優異的反應率使甲 © 醇進行脫水反應。 【實施方式】 本發明的製造二甲醚用觸媒（以下簡稱爲「本發明之 觸媒」），係含有氧化鋁作爲主成分。 氧化鋁係鋁之氧化物，一般係以下述化學式（1 )來 表示。 Α12〇3 * ηΗ2〇[〇 ^ η ^ 0.5] (!) W 就氧化鋁而言，可列舉具有；f相、7相、D相等結晶 相的活性氧化鋁。活性氧化鋁亦可含；t相、r相、D相& 外之結晶相，例如/c相、5相、p相等結晶相。 在本發明之觸媒中，換算爲AhO3之氧化鋁含量，係 以相對於本發明之觸媒而言爲80重量％以上者爲佳，9〇 重量％以上者爲較佳。 在本發明之觸媒中，換算爲Al2〇3之氧化鋁含量，係 意指：在將觸媒所含有的全部鋁成分假定爲式量1〇196 的Al2〇3的情況下，此時的氧化鋁含量。 201031463 在本發明之觸媒中，Al2〇3換算之氧化鋁含量（g)， 係假定爲觸媒僅由八1203、3丨02及Mg構成，而藉由下述 式（1 -1 )求得。201031463 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a catalyst for producing dimethyl ether, which is used for dehydrating methanol to produce dimethyl ether. [Prior Art] In the production method of dimethyl ether [CH3OCH3], a method of dehydrating methanol [CH3OH] in the presence of a catalyst cesium is known, and the catalyst can be generally used. A solid acid catalyst such as alumina. Various catalysts containing cerium oxide or cerium and aluminum oxide are currently being used, and a method for synthesizing dimethyl ether is being reviewed. In Patent Document 1, it is reported that if an aluminosilicate containing 1 to 20% by weight of cerium oxide and 80 to 99% by weight of alumina is used as a catalyst, the carbon is precipitated on the catalyst. Inhibition, so the selectivity of the dehydration reaction of methanol is increased. In the case of using a catalyst having a Si content of 0.1 to 10% by mass and a Na content of 0.1% by mass or less, it is reported that dimethyl ether can be synthesized with high reaction rate and selectivity. In Patent Document 3, it is reported that when a synthetic catalyst composed of at least one of alumina, zirconium, cerium oxide, and titanium oxide as a main component is used, the reaction rate in the synthesis of dimethyl ether And selectivity can be improved. In general, in the synthesis of ether in a high-temperature steam atmosphere, if an alumina catalyst containing no antimony is used, the dehydration characteristics of the catalyst are drastically lowered. On the other hand, in Patent Document 4, a catalyst composed of activated alumina which denatures the surface by a reaction with a ruthenium compound is reported, and if the catalyst is used in this high temperature steam atmosphere, the atmosphere is used in a high-temperature steam atmosphere. In the case of ether synthesis, the dehydration characteristics of the catalyst can still be maintained. [Patent Document 1] JP-A-2006-212557 [Patent Document 3] JP-A-2003-73 No. [Recommended] [Problems to be Solved by the Invention] However, in the case where the dehydration reaction of methanol is carried out using any of the catalysts described in Patent Documents 1 to 4, high reaction can be obtained at the start of the reaction (initial). Rate, however, if the reaction continues for a long time, sufficient reaction rate cannot be maintained. The present invention provides a catalyst for producing dimethyl ether and a method for producing dimethyl ether using the catalyst, which can still carry out a dehydration reaction of methanol at a high reaction rate for a long period of time. [Means for Solving the Problem] The catalyst for producing dimethyl ether of the present invention contains aluminum oxide as a main component, cerium oxide, and magnesium. In the catalyst of the present invention, the cerium oxide content in terms of SiO 2 is preferably 0.01 to 1.2 parts by weight based on 100 parts by weight of the alumina content in terms of Al 2 〇 3 . In the catalyst of the present invention, the content of the magnesium element in terms of Mg is preferably 0.01 to 1.2 parts by weight based on 100 parts by weight of the alumina content of Al2〇3 in 201031463. In the method for producing dimethyl ether of the present invention, methanol is subjected to a dehydration reaction in the presence of a catalyst for producing dimethyl ether of the present invention. [Effect of the Invention] According to the present invention, the dehydration reaction of the methanol can be carried out at an excellent reaction rate over a long period of time. [Embodiment] The catalyst for producing dimethyl ether (hereinafter referred to as "catalyst of the present invention") of the present invention contains alumina as a main component. The alumina-based aluminum oxide is generally represented by the following chemical formula (1). Α12〇3* ηΗ2〇[〇 ^ η ^ 0.5] (!) W In the case of alumina, activated alumina having a crystal phase of f phase, phase 7 and D is exemplified. The activated alumina may also contain a crystal phase other than the t phase, the r phase, the D phase & the outer phase, for example, the /c phase, the 5 phase, and the p crystal phase. In the catalyst of the present invention, the alumina content in terms of AhO3 is preferably 80% by weight or more based on the catalyst of the present invention, and preferably 9% by weight or more. In the catalyst of the present invention, the conversion to the alumina content of Al2〇3 means that when all the aluminum components contained in the catalyst are assumed to be Al2〇3 of the formula amount 1〇196, at this time Alumina content. 201031463 In the catalyst of the present invention, the alumina content (g) in terms of Al2〇3 is assumed to be that the catalyst is composed only of eight 1203, 3丨02, and Mg, and is obtained by the following formula (1 -1). Got it.
Al = ( ( W- ( Sj+M! ) ) ( 1-1 ) 在式（1-1)中，A!係表示換算爲Al2〇3之氧化鋁含 量（g) 、W係表示觸媒之重量（g) 、S!係表示換算爲Al = ( ( Wj ( Sj + M! ) ) ( 1-1 ) In the formula (1-1), A! represents the alumina content (g) converted to Al2〇3, and W represents the catalyst. Weight (g), S! indicates conversion to
Si02之二氧化矽含量（g) 、Μι係表示換算爲Mg之鎂含 量（g )。 Θ 另外，S,係藉由下述式（2-1)求得，Μ!係藉由下述 式（3 -1 )求得。 在本發明之觸媒中，ai2o3換算之氧化鋁之含有比例 (重量％)，係藉由下述式（1-2)求得。 A2= ( ( W- ( Si + Mi ) ) /W ( 1-2 ) 在式（1-2)中，A2係表示換算爲Al2〇3之氧化鋁之 含有比例（重量％ ) 、W係觸媒之重量（g ) 、s 1係表示 換算爲Si02之二氧化矽含量（g)、！^係表示換算爲Mg 〇 之鎂含量（g )。 本發明之觸媒，係含有二氧化矽。本發明之觸媒，藉 由含有二氧化矽，在暴露於高溫高壓水蒸氣環境氣氛時， 觸媒的BET比表面積降低的情形會受到抑制。 在本發明之觸媒中，換算爲Si〇2之二氧化矽含量， 係以相對於ai2o3換算之氧化鋁含量100重量份而言爲 〇·5重量份以上者爲佳，〇.8重量份以上者爲較佳。換算爲 Si02之二氧化矽含量如果少於前述範圍，則在高溫高壓水 -8 - 201031463 蒸氣環境氣氛下，會有氧化鋁轉化成氫氧化鋁的現象發生 ，而所得到觸媒的bet比表面積會有降低的情況。另一方 面，換算爲Si〇2之二氧化矽含量的上限’並未受到特別 限制，而超過一定量，也無法期待BET比表面積之降低抑 制效果更進一步提升。因此，由經濟的觀點看來’換算爲 Si〇2之二氧化矽含量，係以相對於Al2〇3換算之氧化鋁含 量100重量份而言爲10重量份以下者爲佳，2重量份以下 〇 者爲較佳。 在本發明之觸媒中，換算爲Si〇2之二氧化矽含量， 係意指：在觸媒所含全部之矽成分假定爲式量60.08之 Si02的情況下，此時的二氧化矽含量。 在本發明之觸媒中，換算爲Si〇2之二氧化矽含量（g )，係使用藉由ICP發射光譜分析所求得的矽元素含有比 例（重量％ )，藉由下述式（2-1 )求出。The cerium oxide content (g) and Μι of Si02 indicate the magnesium content (g) converted to Mg. Further, S is obtained by the following formula (2-1), and is obtained by the following formula (3 - 1). In the catalyst of the present invention, the content ratio (% by weight) of alumina in terms of ai2o3 is obtained by the following formula (1-2). A2=( ( W - ( Si + Mi ) ) /W ( 1-2 ) In the formula (1-2), A2 represents the content ratio (% by weight) of alumina converted to Al2〇3, and W-touch The weight (g) of the medium, the s 1 system indicates the cerium oxide content (g) converted to SiO 2 , and the γ content indicates the magnesium content (g ) converted to Mg 。. The catalyst of the present invention contains cerium oxide. When the catalyst of the present invention contains cerium oxide, the BET specific surface area of the catalyst is lowered when exposed to a high-temperature high-pressure water vapor atmosphere. In the catalyst of the present invention, it is converted into Si〇2. The cerium oxide content is preferably 5% by weight or more based on 100 parts by weight of the alumina content in terms of ai2o3, preferably 8% by weight or more, and converted to cerium oxide of SiO 2 . If the content is less than the above range, in the high-temperature high-pressure water -8 - 201031463 vapor atmosphere, there will be a phenomenon that alumina is converted into aluminum hydroxide, and the bet specific surface area of the obtained catalyst may be lowered. On the one hand, the upper limit of the content of cerium oxide converted to Si 〇 2 is not particularly limited. When the amount exceeds a certain amount, the effect of suppressing the decrease in the BET specific surface area cannot be expected to be further improved. Therefore, from the economic point of view, the content of cerium oxide converted to Si 〇 2 is determined by the amount of alumina relative to Al 2 〇 3 . 100 parts by weight is preferably 10 parts by weight or less, and preferably 2 parts by weight or less. In the catalyst of the present invention, the conversion to the cerium oxide content of Si 〇 2 means: in the catalyst In the case where all the ruthenium components contained are assumed to be SiO 2 having a formula of 60.08, the cerium oxide content at this time. In the catalyst of the present invention, the cerium oxide content (g) converted to Si 〇 2 is used. The niobium element content ratio (% by weight) obtained by ICP emission spectrometry was determined by the following formula (2-1).
Si=Wx(S2/100) X ( 60.08/28.09 ) ( 2- 1 ) ® 在式（2-1 )中，S,係表示換算爲Si〇2之二氧化矽含 量（g) 、W係表示觸媒之重量（g) 、S2係表示矽元素之 含有比例（重量％ ) 、60.08係表示Si02之式量、28.09係 表示S 1之原子量。 在本發明之觸媒中，相對於換算爲Α12〇3之氧化鋁含 量100重量份而言，換算爲Si 02之二氧化矽含量（g)， 係藉由下述式（2-2 )求得。 S = Si X 1 00/ ( Wx ( A2/l 00 ) ) (2-2) 在式（2-2)中，S係表示相對於換算爲Al2〇3之氧化 201031463 鋁含量100重量份而言，換算爲Si〇2之二氧化矽含量（g )、Si係表示換算爲Si02之二氧化矽含量（g) 、W係表 示觸媒之重量（g) 、A2係表不換算爲Al2〇3之氧化銘之 含有比例（重量％)。 本發明之觸媒’係含有鎂元素。本發明之觸媒含有鎂 元素的設計，能對於經過長時間仍然以高反應率使甲醇進 行脫水反應的目標有所貢獻。另外’在本發明之觸媒中， 係以氧化鎂（MgO )之形態含有鎂元素。 ® 在本發明之觸媒中，換算爲Mg之鎂元素含量’係以 相對於換算爲A1203之氧化鋁含量1〇〇重量份而言爲〇·〇1 〜1.2重量份者爲佳’ 0.1〜〇.6重量份者爲較佳。換算爲 Mg之鎂元素含暈，如果少於前述範圍’則鎂兀素的含有 效果會有變成不足的情形’若將所得到之觸媒供應至長時 間反應，則會有無法維持充分反應率之虞。另一方面，換 算爲Mg之鎂元素含量如果高於前述範圍，則在使用所得 到之觸媒的甲醇脫水反應中，反應開始時（初期）之反應 ® 率會有降低的情形，也會有無法有效率地製造二甲醚的情 況。 在本發明之觸媒中，換算爲Mg之鎂元素含量，係意 指觸媒所含全部之Mg成分假定爲原子量24.31之Mg的 情況下，此時的鎂元素含量。 在本發明之觸媒中，換算爲Mg之鎂含量（g)，係使 用藉由例如ICP發射光譜分析所求得的鎂元素含有比例（ 重量％)，由下述式（3-1)求出。 -10- 201031463 Μι = WxM2/1〇〇 ( 3-1 ) 在式（3-1)中，係表示換算爲Mg之鎂含量（g) 、W係表示觸媒之重量（g) 、M2係表示鎂元素之含有比 例（重量％ )。 在本發明之觸媒中，相對於換算爲A12〇3之氧化銘含 量100重量份而言，換算爲Mg之鎂元素含量（g) ’係藉 由下述式（3-2 )求得。 φ M = Mj X 1 00/ ( Wx ( A2/l 00 ) ) (3-2) 式（3-2 )中，M係表示相對於換算爲A1203之氧化鋁 含量100重量份而言，換算爲Mg之錶元素含量（g) ； S, 係表示換算爲Mg之鎂元素含量（g) ; W係表示觸媒之 重量（g) ;a2係表示換算爲ai2o3之氧化鋁之含有比例 (重量％ )。 本發明之觸媒，在不損及本發明效果之範圍，亦可含 有例如鈦、铈、銷、鋅等、鋁及鎂以外之金屬元素。另外 ® ，在本發明之觸媒中，能夠以氧化物之形態含有該等鋁及 鎂以外之金屬元素。 在本發明之觸媒中，Na20換算之鈉含量，係以0.01 重量％以下爲佳，理想的情況下，係以實質上不含鈉者（0 重量％)爲較佳。Na20換算之鈉含量如果超過〇.〇1重量％ ，則所得到之觸媒之反應率有降低的情形。 本發明之觸媒，在其使用前的BET比表面積係以 100m2/g以上、300m2/g以下爲佳。 本發明之觸媒之中，具有1.8nm〜100// m之細孔半徑 -11 - 201031463 的細孔之累計容積，係以〇.3cm3/g以上、3.0cm3/g以下爲 佳。另外，具有100nm〜100#m之細孔半徑的細孔之累 計容積，相對於具有1 .8nm〜100 A m之細孔半徑的細孔之 累計容積而言，係以約10%〜約60%爲佳，約15%〜約 50%者爲較佳。 本發明之觸媒，係可藉由例如： i) 藉由使含二氧化矽源及鎂源的溶液充分地被氧化 鋁前驅物吸收，得到吸收氧化鋁前驅物之後，將所得到之 © 吸收氧化鋁前驅物加以燒成的方法、 ii) 藉由將粉體的二氧化矽源、粉體的鎂源及粉體的 氧化鋁前驅物加以混合，得到混合物，將所得到之混合物 加以燒成的方法、 iii )藉由將氧化鋁前驅物加以燒成，得到燒成體，對 所得到之燒成體賦予二氧化矽源及鎂源的方法， 等方式製造出來。 就本發明之觸媒所含的二氧化矽之來源（以下亦稱爲 © 二氧化矽源）而言，並未受到特別限制，而可使用例如酸 性二氧化矽溶膠、中性二氧化矽溶膠等二氧化矽溶膠液、 二氧化矽粉末、正矽酸四乙酯等矽烷氧化物等。二氧化矽 源，係以不含鋁及鎂以外之金屬元素者爲佳。 就本發明之觸媒所含之鎂元素（以下亦稱爲鎂源）而 言，並未受到特別限制，而可使用例如硫酸鎂、醋酸鎂、 硝酸鎂、氯化鎂、氫氧化鎂等各種錶鹽、氧化鎂之粉末等 -12- 201031463 前述任一種方法中，所使用的氧化鋁前驅物，皆爲藉 由燒成而產生出氧化鋁的物質，就氧化鋁前驅物而言，並 無特別限制，可使用藉著以往周知的方法所得到之氧化鋁 前驅物’或者可使用市售之氫氧化鋁、市售的氧化鋁等。 另外，在任一種方法中，對於燒成條件而言皆並無特別限 制，而燒成溫度係以約400°C〜約1 100 °C爲佳，燒成時間 係以約2小時〜約24小時爲佳，燒成環境氣氛，係以空 Φ 氣環境氣氛爲佳。 在前述i)的方法中，含前述二氧化矽源及前述鎂源 的溶液，係以水溶液爲佳。 在前述i)的方法中，就使前述溶液被氧化鋁前驅物 吸收的方式而言，可列舉將氧化鋁前驅物浸漬在前述溶液 中的方法、將前述溶液塗佈在氧化鋁前驅物的方法等。另 外’在前述i)的方法中，使含前述二氧化矽源及前述鎂 源的溶液被氧化鋁前驅物吸收之情況，可使用含前述二氧 ® 化矽源與前述鎂源兩者的溶液，或者亦可將含前述二氧化 矽源的溶液、與含前述鎂源的溶液各自分別被氧化鋁前驅 物吸收。 在前述ii )的方法中，混合的方式並未受到特別限制 ’可列舉例如像是攪拌機這種將粉體加以攪拌的方式、像 是磨碾機這種一面進行粉碎同時加以混合的方式等。 另外，前述i)的方法與前述ii)的方法，亦可將其 加以組合。就將前述i )的方法與前述i i )的方法加以組 合的方法而言’可列舉例如藉由將粉體的前述二氧化矽源 -13- 201031463 與氧化鋁前驅物加以混合而得到混合物，使所得到之混合 物吸收前述鎂源溶液的方法；藉由將粉體的前述鎂源與氧 化鋁前驅物加以混合而得到混合物，使所得到之混合物吸 收前述二氧化矽源溶液的方法等。 本發明之觸媒，在二甲醚的製造中，以例如粉末狀的 狀態使用亦可，而以球狀成形體的形式使用爲佳。在將本 發明之觸媒製成成形體的情況下，在前述i)的方法中’ 對吸收前述溶液之前，或吸收前述溶液之後的氧化鋁前驅 @ 物實施成形加工皆可；在前述ii)的方法中，亦可藉由將 前述二氧化矽源、前述鎂源及氧化鋁前驅物加以混合，對 所得到的混合物實施成形加工，在前述任一種方法之中， 亦可對燒成後所得到的觸媒實施成形加工。就成形方法而 言，並無特別限制，可以例如轉動造粒法、壓製成形法、 打錠成形法、擠製成形法等方法來進行。另外，在進行成 形加工的時候，爲了使成形性提升，亦可預先使氧化鋁前 驅物變成適當的粒度分布而粉碎備用。另外，在進行成形 © 加工的時候，可使用黏結劑，例如可使用含水、二氧化矽 溶膠、氧化鋁溶膠等氧化物溶膠液、硝酸鋁、硝酸鎂、醋 酸鎂等金屬鹽的水溶液等作爲黏結劑。 就使用本發明之觸媒製造二甲醚的方法而言，可列舉 例如在本發明之觸媒的存在下使甲醇進行脫水反應的方法 ，具體而言，可列舉於甲醇脫水反應溫度使甲醇氣體與本 發明之觸媒接觸方法。 甲醇氣體，可爲僅由甲醇所構成之純甲醇氣體，而亦 -14- 201031463 可爲含有水（水蒸氣）及/或乙醇、異丙醇等甲醇以外的 醇之不純甲醇氣體。在不純甲醇氣體之中，甲醇之含量， 係以90重量％以上爲佳’ 95重量％以上者爲較佳。另外， 就甲醇氣體而言’甲醇氣體可使用經過氮、氬、氦等惰性 氣體等稀釋的稀釋甲醇氣體。 甲醇氣體，可藉由使甲醇氣化而獲得。甲醇的氣化， 可藉由使用熱交換器等而進行。 Φ 甲醇脫水反應之溫度’係以250°C以上爲佳，27CTC以 上爲較佳，450 °C以下爲佳，400 °C以下爲較佳。甲醇脫水 反應時之反應壓力，係依照反應溫度而有所不同，而以 50><105Pa以下爲佳，lxl〇5Pa以上、3〇xl〇5pa以下爲較佳 〇 甲醇脫水反應，可使用像是多管式反應器這種固定床 反應器來進行。在甲醇脫水反應中，甲醇的空間速度係以 50 01Γ1以上、1 500001Γ1以下爲佳。 β 藉由甲醇脫水反應所得到的二甲醚，亦可以蒸餾等方 法進行精製。 [實施例] 以下藉由實施例對於本發明作更詳細地說明，而本發 明不會受到這些實施例所限定。 在以下的實施例、比較例之中，所得到之觸媒中之二 氧化矽及鎂元素含量與所得到之觸媒的ΒΕΤ比表面積’係 藉由以下方法進行測定。 -15- 201031463 <二氧化矽（Si〇2)含量、鎂元素（Mg)含量〉 將觸媒粉碎，加入碳酸鈉及硼酸’在1050 1燒成之後 ，加入硝酸，製作出試樣液。藉由對此試樣液實施1CP發 射光譜分析’求得矽元素量及鎂元素量’該觸媒視爲僅由 Al2〇3、Mg及Si〇2所構成者，分別針對於二氧化矽含量 ，算出相對於換算爲Al2 〇3之氧化鋁1〇〇重量份而言的 Si02含量；針對於鎂元素含量，算出相對於換算爲Al2〇3 之氧化鋁100重量份而言的Mg含量。 © < BET比表面積> 使用全自動BET比表面積測定裝置（Mountech股份 有限公司製「Macsorb Model-1201」’藉由單點法測定 BET比表面積。 (實施例1 ) 將水鋁礦結晶氫氧化鋁（Almatis公司製「HIQ— 40」 @ )以振動磨機粉碎至中心粒徑7.5 // m爲止，得到粉碎物 品。將此粉碎物品置於600°C燒成2小時，得到氧化鋁。 所得到之氧化鋁係具有7結晶相，Na20量爲0.001重量％ 以下。 接下來，將氧化鋁溶膠（日產化學製「氧化鋁溶膠 520j :在溶膠中每單位氧化鋁中的Na20量爲0.001重量 %以下）稀釋1 〇倍形成的液體噴灑而添加於上述粉碎物品 ，同時使用攪拌機進行造粒，製成直徑2〜4mm之球狀成 -16- 201031463 形體，將此成形體置於200°C而使其乾燥，得到氫氧化鋁 成形體。 使此氫氧化鋁成形體122g充分地吸收由醋酸鎂四水 合物[Mg(CH3COO)2· 4H20]1.8g溶解於水28.7g所形成的 水溶液，之後以乾燥機使其於200°C乾燥2小時左右。接 著，使經過乾燥後的成形體充分地吸收將二氧化矽溶膠（ 日產化學工業股份有限公司製「SNOWTEX N」）5g與水 Φ 27.5g加以混合所形成的二氧化矽溶膠液，於室溫放置6 小時左右使其乾燥之後，將所得到之成形體置於600°C進 行燒成，而得到觸媒（1 )。 所得到之觸媒（1 )，係以氧化鋁作爲主成分的觸媒 ，並且相對於換算爲ai2o3之氧化鋁100重量份，含有換 算爲Si02之二氧化矽0.91重量份，同時，相對於換算爲 Al2〇3之氧化銘100重量份而言，含有換算爲Mg之鎂元 素0.16重量份。另外，此觸媒（1 )之BET比表面積爲 ® 1 77m2/g。 (實施例2 ) 與實施例1相同之方式所得到之氫氧化鋁成形體1 22g ，充分地使其吸收由硝酸鎂六水合物[Mg(N03)2 · 6H20]4.3g與二氧化矽溶膠（日產化學工業股份有限公司 製「SNOWTEX 0」）5.1g混合至水24.0g並使其溶解形 成的溶膠液，於室溫放置6小時程度而使其乾燥之後，將 所得到之成形體置於600°C進行燒成，得到觸媒（2)。 -17- 201031463 所得到之觸媒（2 )，係以氧化鋁作爲主成分的觸媒 ，相對於換算爲Al2〇3之氧化鋁100重量份而言，含有換 算爲Si02之二氧化矽0.95重量份，同時，相對於換算爲 Al2〇3之氧化銘100重量份，含有換算爲Mg之鎂元素 0.42重量份。另外，此觸媒（2)之 BET比表面積爲 1 99m2/g ° (實施例3 ) ❹Si=Wx(S2/100) X ( 60.08/28.09 ) ( 2 - 1 ) ® In the formula (2-1), S represents the cerium oxide content (g) converted to Si 〇 2, and the W system represents The weight of the catalyst (g), S2 indicates the content ratio of the lanthanum element (% by weight), 60.08 indicates the formula of SiO 2 , and 28.09 indicates the atomic weight of S 1 . In the catalyst of the present invention, the content (g) of the cerium oxide converted to Si 02 is calculated by the following formula (2-2) with respect to 100 parts by weight of the alumina content converted to Α12〇3. Got it. S = Si X 1 00/ ( Wx ( A2/l 00 ) ) (2-2) In the formula (2-2), the S system represents that the amount of the aluminum content is 100 parts by weight with respect to the oxidation of Al2〇3, 201031463. , the content of cerium oxide (g) converted to Si 〇 2, the cerium oxide content (g) converted to SiO 2 by Si, the weight (g) of catalyst by W system, and the conversion of A2 system to Al 2 〇 3 The proportion of the oxidation of the inscription (% by weight). The catalyst ' of the present invention contains magnesium. The catalyst of the present invention contains a magnesium element and contributes to the goal of dehydrating methanol at a high reaction rate for a long period of time. Further, in the catalyst of the present invention, magnesium is contained in the form of magnesium oxide (MgO). In the catalyst of the present invention, the content of magnesium element in terms of Mg is preferably 0.1 to 1.2 parts by weight relative to 1 part by weight of the alumina content converted to A1203. 6. 6 parts by weight is preferred. The magnesium element converted to Mg contains halo. If it is less than the above range, the effect of magnesium strontium may become insufficient. If the obtained catalyst is supplied to a long-term reaction, sufficient reaction rate cannot be maintained. After that. On the other hand, if the content of the magnesium element converted to Mg is higher than the above range, the reaction rate at the start of the reaction (initial) may be lowered in the methanol dehydration reaction using the obtained catalyst, and there may be a case The case of dimethyl ether cannot be efficiently produced. In the catalyst of the present invention, the content of the magnesium element in terms of Mg means that the content of the magnesium element at this time in the case where all the Mg components contained in the catalyst are assumed to be Mg of an atomic amount of 24.31. In the catalyst of the present invention, the magnesium content (g) converted to Mg is a magnesium element content ratio (% by weight) obtained by, for example, ICP emission spectral analysis, and is obtained by the following formula (3-1). Out. -10- 201031463 Μι = WxM2/1〇〇( 3-1 ) In the formula (3-1), the magnesium content (g) converted to Mg, the W system indicates the weight of the catalyst (g), and the M2 system Indicates the content ratio (% by weight) of magnesium. In the catalyst of the present invention, the magnesium element content (g)' converted to Mg is obtained by the following formula (3-2) with respect to 100 parts by weight of the oxidized content of A12〇3. φ M = Mj X 1 00 / ( Wx ( A2 / l 00 ) ) (3-2) In the formula (3-2), the M system is expressed in terms of 100 parts by weight of the alumina content converted to A1203, and is converted into The content of the surface element of Mg (g); S, the content of magnesium element (g) converted to Mg; the weight of the catalyst (g) of W; the a2 is the content of alumina converted to ai2o3 (% by weight) ). The catalyst of the present invention may contain a metal element other than aluminum, magnesium, or the like, such as titanium, tantalum, pin, zinc, or the like, without departing from the effects of the present invention. Further, in the catalyst of the present invention, metal elements other than aluminum and magnesium can be contained in the form of an oxide. In the catalyst of the present invention, the sodium content in terms of Na20 is preferably 0.01% by weight or less, and preferably, sodium (0% by weight) is substantially not contained. If the sodium content in terms of Na20 exceeds 〇.〇1% by weight, the reaction rate of the obtained catalyst may be lowered. The catalyst of the present invention preferably has a BET specific surface area of from 100 m 2 /g to 300 m 2 /g or less before use. Among the catalysts of the present invention, the cumulative volume of the pores having a pore radius of from -11 to 201031463 of from 1.8 nm to 100/m is preferably from 3 cm 3 /g to 3.0 cm 3 /g. Further, the cumulative volume of the pores having a pore radius of 100 nm to 100 #m is about 10% to about 60 with respect to the cumulative volume of the pores having a pore radius of 1.8 nm to 100 Å. % is preferred, and about 15% to about 50% is preferred. The catalyst of the present invention can be obtained by, for example, i) absorbing the alumina precursor by allowing the solution containing the cerium oxide source and the magnesium source to be sufficiently absorbed by the alumina precursor to obtain the absorbing alumina precursor. a method of calcining an alumina precursor, ii) mixing a powder of a cerium oxide source, a magnesium source of a powder, and an alumina precursor of a powder to obtain a mixture, and firing the obtained mixture The method iii) is produced by firing an alumina precursor to obtain a fired body, and applying a cerium oxide source and a magnesium source to the obtained fired body. The source of the cerium oxide (hereinafter also referred to as cerium dioxide source) contained in the catalyst of the present invention is not particularly limited, and for example, an acidic cerium oxide sol or a neutral cerium oxide sol can be used. A cerium oxide such as cerium oxide sol liquid, cerium oxide powder or tetraethyl orthosilicate. The source of cerium oxide is preferably a metal element other than aluminum or magnesium. The magnesium element (hereinafter also referred to as a magnesium source) contained in the catalyst of the present invention is not particularly limited, and various surface salts such as magnesium sulfate, magnesium acetate, magnesium nitrate, magnesium chloride, magnesium hydroxide, and the like can be used. Magnesium oxide powder, etc. -12-201031463 In any of the above methods, the alumina precursor used is a substance which generates alumina by firing, and there is no particular limitation on the alumina precursor. An alumina precursor obtained by a conventionally known method can be used, or commercially available aluminum hydroxide or commercially available alumina can be used. Further, in any of the methods, the firing conditions are not particularly limited, and the firing temperature is preferably from about 400 ° C to about 1 100 ° C, and the firing time is from about 2 hours to about 24 hours. It is better to burn the ambient atmosphere with an air atmosphere of Φ. In the method of the above i), the solution containing the source of the cerium oxide and the magnesium source is preferably an aqueous solution. In the method of the above i), a method of absorbing the solution by the alumina precursor includes a method of immersing the alumina precursor in the solution, and a method of applying the solution to the alumina precursor. Wait. Further, in the method of the above i), in the case where the solution containing the source of the cerium oxide and the magnesium source is absorbed by the alumina precursor, a solution containing both the source of the dioxin and the source of the magnesium may be used. Alternatively, the solution containing the source of the cerium oxide and the solution containing the magnesium source may be separately absorbed by the alumina precursor. In the method of the above ii), the method of mixing is not particularly limited, and examples thereof include a method of stirring a powder such as a stirrer, and a method of pulverizing and mixing while grinding a surface. Further, the method of the above i) and the method of the above ii) may be combined. In the method of combining the method of the above i) with the method of the above ii), for example, a mixture of the above-mentioned ceria source-13-201031463 of a powder and an alumina precursor is used to obtain a mixture. A method of absorbing the magnesium source solution by the obtained mixture; a method of obtaining a mixture by mixing the magnesium source of the powder and an alumina precursor to obtain a mixture of the obtained cerium oxide source solution. The catalyst of the present invention may be used in the form of a powdery form in the production of dimethyl ether, and may be preferably used in the form of a spherical shaped body. In the case where the catalyst of the present invention is formed into a molded body, in the method of the above i), the alumina precursor may be subjected to a forming process before the absorption of the solution or after the absorption of the solution; in the foregoing ii) In the method, the obtained mixture may be subjected to a molding process by mixing the source of the cerium oxide, the magnesium source and the alumina precursor, and in any of the above methods, The obtained catalyst was subjected to forming processing. The molding method is not particularly limited, and it can be carried out, for example, by a method such as a tumbling granulation method, a press molding method, a tablet forming method, or a extrusion molding method. Further, in the case of performing the forming process, in order to improve the moldability, the alumina precursor may be previously prepared into an appropriate particle size distribution and pulverized for use. Further, when performing the forming process, a binder may be used. For example, an aqueous solution of an oxide sol such as water, cerium oxide sol or alumina sol, or a metal salt of a metal salt such as aluminum nitrate, magnesium nitrate or magnesium acetate may be used as the bonding. Agent. The method for producing dimethyl ether using the catalyst of the present invention may, for example, be a method in which methanol is subjected to a dehydration reaction in the presence of a catalyst of the present invention, and specifically, a methanol gas may be exemplified at a methanol dehydration reaction temperature. Contact method with the catalyst of the present invention. The methanol gas may be a pure methanol gas composed only of methanol, and -14-201031463 may be an impure methanol gas containing an alcohol other than methanol such as water (steam) and/or ethanol or isopropyl alcohol. Among the impure methanol gas, the content of methanol is preferably 90% by weight or more, preferably 95% by weight or more. Further, as the methanol gas, the methanol gas may be a diluted methanol gas diluted with an inert gas such as nitrogen, argon or helium. Methanol gas can be obtained by vaporizing methanol. The gasification of methanol can be carried out by using a heat exchanger or the like. The temperature of the Φ methanol dehydration reaction is preferably 250 ° C or more, more preferably 27 CTC or more, more preferably 450 ° C or less, and preferably 400 ° C or less. The reaction pressure in the dehydration reaction of methanol differs depending on the reaction temperature, and is preferably 50> or less, and lxl〇5Pa or more and 3〇xl〇5pa or less are preferred methanol dehydration reaction, and an image can be used. It is a multi-tubular reactor such as a fixed bed reactor. In the methanol dehydration reaction, the space velocity of methanol is preferably 50 01 Γ 1 or more and 1 500001 Γ 1 or less. The dimethyl ether obtained by the methanol dehydration reaction can also be purified by distillation or the like. [Examples] Hereinafter, the present invention will be explained in more detail by way of examples, but the present invention is not limited by the examples. In the following examples and comparative examples, the content of ruthenium dioxide and magnesium in the obtained catalyst and the specific surface area of ruthenium of the obtained catalyst were measured by the following methods. -15- 201031463 <Cerium dioxide (Si〇2) content and magnesium element (Mg) content> The catalyst was pulverized, and sodium carbonate and boric acid were added. After firing at 1050 1, nitric acid was added to prepare a sample solution. By performing 1CP emission spectroscopy analysis on the sample solution to obtain the amount of lanthanum element and the amount of magnesium element, the catalyst is considered to be composed only of Al2〇3, Mg and Si〇2, respectively, for the content of cerium oxide. The SiO 2 content is calculated for 1 part by weight of the alumina converted to Al 2 〇 3, and the Mg content is calculated for 100 parts by weight of the alumina converted to Al 2 〇 3 for the magnesium element content. © < BET specific surface area> The BET specific surface area was measured by a single point method using a fully automatic BET specific surface area measuring device ("Macsorb Model-1201" manufactured by Mountech Co., Ltd.) (Example 1) Alumina ("HIQ-40" manufactured by Almatis Co., Ltd.) was pulverized by a vibration mill to a center particle diameter of 7.5 // m to obtain a pulverized article. The pulverized article was baked at 600 ° C for 2 hours to obtain alumina. The alumina obtained has a 7-crystalline phase, and the amount of Na20 is 0.001% by weight or less. Next, an alumina sol (aluminum sol 520j manufactured by Nissan Chemical Co., Ltd.: Na20 amount per unit alumina in the sol is 0.001% by weight) % or less) The liquid formed by diluting 1 〇 times is sprayed and added to the pulverized article, and granulated using a stirrer to form a spherical shape of -16 to 201031463 having a diameter of 2 to 4 mm, and the molded body is placed at 200 ° C. The aluminum hydroxide molded body was dried to obtain an aqueous solution formed by dissolving 1.8 g of magnesium acetate tetrahydrate [Mg(CH3COO) 2 · 4H20] in 28.7 g of water. After drying The machine was dried at 200 ° C for about 2 hours. Then, the dried molded body was sufficiently absorbed to mix 5 g of cerium oxide sol ("SNOWTEX N" manufactured by Nissan Chemical Co., Ltd.) with water Φ 27.5 g. The formed cerium oxide sol solution was allowed to stand at room temperature for about 6 hours to be dried, and then the obtained molded body was baked at 600 ° C to obtain a catalyst (1). The obtained catalyst ( 1), a catalyst containing alumina as a main component, and containing 0.91 part by weight of cerium oxide converted to SiO 2 with respect to 100 parts by weight of alumina converted to ai 2o 3 , and oxidation with respect to Al 2 〇 3 In 100 parts by weight, 0.16 parts by weight of the magnesium element in terms of Mg is contained, and the BET specific surface area of the catalyst (1) is о 1 77 m 2 /g. (Example 2) The same manner as in Example 1 22 g of the obtained aluminum hydroxide molded body was sufficiently absorbed by 4.3 g of magnesium nitrate hexahydrate [Mg(N03) 2 · 6H20] and cerium oxide sol ("SNOWTEX 0" manufactured by Nissan Chemical Industries, Ltd.) 5.1g was mixed into water 24.0g and dissolved to form After the sol solution was allowed to stand at room temperature for 6 hours and dried, the obtained molded body was baked at 600 ° C to obtain a catalyst (2). -17- 201031463 The obtained catalyst (2) The catalyst containing alumina as a main component contains 0.95 parts by weight of cerium oxide in terms of SiO 2 and 100 parts by weight of Al 2 〇 3 in terms of conversion to Al 2 〇 3 Oxidation 100 parts by weight, containing 0.42 parts by weight of magnesium element converted to Mg. Further, the catalyst (2) has a BET specific surface area of 1 99 m 2 /g ° (Example 3) ❹
與實施例1相同之方式所得到之氫氧化鋁成形體122g ，充分地使其吸收、由二氧化矽溶膠（日產化學工業股份 有限公司製「SNOWTEX N」）5.1g與水25.2g混合所形 成的二氧化矽溶膠液，之後以乾燥機使其於200°C乾燥2 小時左右。接著，使乾燥過後的成形體充分地吸收由醋酸 鎂四水合物[Mg(CH3COO)2· 4H20]6.2g溶解於水27.2g所 形成的水溶液，於室溫放置6小時左右使其乾燥之後，將 所得到之成形體置於600°C進行燒成，而得到觸媒（3 ) 。 H 所得到之觸媒（3 )，係以氧化鋁作爲主成分的觸媒 ，並且相對於換算爲ai2o3之氧化鋁100重量份’含有換 算爲Si02之二氧化矽1.02重量份’同時’相對於換算爲 Al2〇3之氧化鋁100重量份而言’含有換算爲Mg之鎂元 素0.5 7重量份。另外，此觸媒（3)之BET比表面積爲 1 84m2/g 〇 (實施例4) • 18 - 201031463 與實施例1相同之方式所得到之氫氧化鋁成形體1 22g ，充分地使其吸收硝酸鎂六水合物[Mg(N03j2· 6H20]7.4g 與二氧化矽溶膠（日產化學工業股份有限公司製「 SNOWTEX Ο」）5.1g與水23.1g混合、溶解所形成的溶 膠液，於室溫放置6小時左右使其乾燥之後，將所得到之 成形體置於600°C進行燒成，而得到觸媒（4 )。 所得到之觸媒（4 )，係以氧化鋁作爲主成分的觸媒 ❹ ，並且相對於換算爲Al2〇3之氧化鋁100重量份而言，含 有換算爲Si〇2之二氧化矽0.87重量份，同時’相對於換 算爲Al2〇3之氧化鋁100重量份而言，含有換算爲Mg之 鎂元素0.62重量份。另外，此觸媒（4)之BET比表面積 爲 199m2/g。 (比較例1 ) 在實施例1中，不使氫氧化鋁成形體吸收醋酸鎂四水 ® 合物溶於水所形成的水溶液及二氧化矽溶膠液這兩者，除 此之外，係以與實施例1相同之方式，得到觸媒（C1 )。 所得到之觸媒（C 1 )，係以氧化鋁作爲主成分的觸媒 ，相對於換算爲Al2〇3之氧化鋁100重量份而言’含有換 算爲Si02之二氧化矽0.03重量份，同時’相對於換算爲 Al2〇3之氧化鋁100重量份而言，含有換算爲Mg之錶元 素0.00重量份。另外，此觸媒（C1)之BET比表面積爲 171m2/g。另外，儘管沒有使用二氧化矽溶膠液’觸媒（ C1)含有微量之二氧化矽的現象，是因爲來自於雜質。 -19 - 201031463 (比較例2) 與實施例1相同之方式所得到之氫氧化鋁成形體122g ，充分地使其吸收混合二氧化矽溶膠（日產化學工業股份 有限公司製「SNOWTEX N」）5.0g與水25.2g的二氧化 矽溶膠液，於室溫放置6小時左右使其乾燥之後，將所得 到之成形體置於60(TC進行燒成，而得到觸媒（C2 )。 所得到之觸媒（C2 )，係以氧化鋁作爲主成分的觸媒 ，相對於換算爲A1203之氧化鋁100重量份而言，含有換 φ 算爲Si〇2之二氧化矽0.97重量份，同時，相對於換算爲 Al2〇3之氧化銘1〇〇重量份而言，含有換算爲Mg之鎂元 素0.00重量份。另外，此觸媒（C2)之BET比表面積爲 1 78m2/g。 對於以上實施例及比較例所得到之觸媒（1 )〜（4 ) 及（C1)〜（C2)，藉著下述方法，評估二甲醚連續製造 時之觸媒活性（反應率）之維持率，以及在高溫高壓水蒸 氣環境氣氛下的BET比表面積之下降率。將各觸媒之物性 @ 與結果一起表示於表1。 <觸媒活性之維持率> 分別使用各觸媒’以固定床流通式反應裝置，於溫度 2 90 °C、壓力IMP aG之條件下，使甲醇液體（和光純藥股 份有限公司製，特級）氣化’並以空間速度（SV ) 20001Γ1 供給，藉此進行甲醇脫水反應，連續製造出二甲醚。由反 應開始經過約2小時（初期）與經過7天時間之後的反應 -20- 201031463 率，係如以下之方式求得。亦即，由反應開始經過約2小 時後以及7天時間之後’對反應裝置的出口氣體進行取樣 ，測定出口氣體的甲醇濃度OMeOH (莫耳濃度）’反應 裝置入口氣體的甲醇濃度IMeOH定爲100%，由該等甲醇 濃度，依照下式（1 )分別求出初期及7天後的甲醇反應 率（％ )。由所得到之初期以及7天後的甲醇反應率’依 照下式（2)算出反應率之維持率（％)、將所算出的反應 Φ 率之維持率，視爲二甲醚連續製造時之觸媒活性之維持率 而進行評估。 甲醇反應率（％)=[ (IMeOH-OMeOH) /IMeOH]xl〇〇 (1) 維持率（％) =[ (7天後的甲醇反應率）/ (初期的甲醇反應率）] xlOO (2) < BET比表面積之下降率> 分別對各觸媒，使用高壓高壓滅菌釜（楠本化成股份 φ 有限公司製「PCT-2〇0-l〇」）於l5〇t、飽和水蒸氣中處 理24小時。由處理前後之BET比表面積，依照下式（3 ) 算出下降率（％) ’藉此評估在高溫高壓水蒸氣環境氣氛 下的bet比表面積下降率。 下降率（％)=[(處理前之BET比表面積一處理後之BET比表面 積）/ (處理前之BET比表面積）]X100 (3) -21 - 201031463 [表i] ※ Si02含量 ※ Mg含量 反應率 BET比麵 δ積 初期 7天後 維持率 處理前 處理後 下降率 (重量份） (重量份） (%) (%) (%) (m2/g) (m2/g) (%) 實施例1 0.91 0.16 78.3 73.5 93.9 177 121 31.8 實施例2 0.95 0.42 77.4 73.8 95.3 199 117 41.4 實施例3 1.02 0.57 74.7 72.3 96.8 184 103 44.2 實施例4 0.87 0.62 74.2 71.1 95.8 199 125 37.1 比較例1 0.03 0.00 78.3 70.9 90.5 171 51 70.5 比較例2 0.97 0.00 78.0 70.9 90.9 178 123 30.6 含量及Mg含量，係以相對於換算爲Al2〇3之氧化鋁100重量份而言的重量份 來表示。 由表1可知，含有鎂元素的實施例1〜4觸媒，觸媒活 性之維持率高，即使經過7天之後’仍然能夠以高反應率 使甲醇進行脫水反應。相對於此’不含鎂元素的比較例1 及2觸媒的情況中，可知觸媒活性之維持率低’即使初期 表現出高反應率，如果供應至長時間反應’則反應率還是 會顯著降低。 @ 另外，若將比較例1與比較例2加以比較’則可明白 在二氧化矽含量極少的情況下，因爲暴露於高溫高壓水蒸 氣環境氣氛下，觸媒的BET比表面積會顯著降低。由此現 象可知，將本發明之觸媒’在高溫高壓水蒸氣環境氣氛下 供應至脫水反應時’相對於換算爲A12〇3之氧化鋁1 00重 量份，以含有換算爲si〇2之二氧化矽0.5重量份以上爲適 合。 -22-The aluminum hydroxide molded article 122g obtained in the same manner as in the first embodiment was sufficiently absorbed and mixed with 5.1 g of cerium oxide sol ("SNOWTEX N" manufactured by Nissan Chemical Industries, Ltd.) and 25.2 g of water. The cerium oxide sol solution was then dried in a dryer at 200 ° C for about 2 hours. Then, the dried molded body was sufficiently absorbed into an aqueous solution prepared by dissolving 6.2 g of magnesium acetate tetrahydrate [Mg(CH3COO) 2 · 4H20] in 27.2 g of water, and allowed to stand at room temperature for about 6 hours to dry. The obtained molded body was baked at 600 ° C to obtain a catalyst (3). The catalyst (3) obtained by H is a catalyst containing alumina as a main component, and contains 100 parts by weight of alumina converted to ai2o3, containing 1.02 parts by weight of cerium oxide converted to SiO 2 'at the same time' In terms of 100 parts by weight of the alumina converted to Al 2 〇 3, 'containing 0.77 parts by weight of the magnesium element converted to Mg. Further, the catalyst (3) had a BET specific surface area of 1,84 m 2 /g 〇 (Example 4) • 18 - 201031463 The aluminum hydroxide molded body 1 22g obtained in the same manner as in Example 1 was sufficiently absorbed. Magnesium nitrate hexahydrate [Mg (N03j2·6H20] 7.4g and 5.1g of cerium oxide sol ("SNOWTEX 制" manufactured by Nissan Chemical Co., Ltd.) and 23.1g of water were mixed and dissolved to form a sol solution at room temperature. After leaving it to dry for about 6 hours, the obtained molded body was baked at 600 ° C to obtain a catalyst (4). The obtained catalyst (4) was touched with alumina as a main component. The medium contains 0.87 parts by weight of cerium oxide converted to Si 〇 2 and 100 parts by weight with respect to alumina converted to Al 2 〇 3 with respect to 100 parts by weight of alumina converted to Al 2 〇 3 . In addition, the catalyst (4) had a BET specific surface area of 199 m 2 /g. (Comparative Example 1) In Example 1, the aluminum hydroxide molded body was not absorbed into the acetic acid. An aqueous solution of magnesium tetrahydrate® dissolved in water and a cerium oxide sol solution In addition, a catalyst (C1) was obtained in the same manner as in Example 1. The obtained catalyst (C1) was a catalyst containing alumina as a main component, and was converted into Al2. 100 parts by weight of the alumina of 〇3, 'containing 0.03 parts by weight of cerium oxide converted to SiO 2 and 'with respect to 100 parts by weight of alumina converted to Al 2 〇 3, containing 0.00 weight of the surface element converted to Mg Further, the catalyst (C1) has a BET specific surface area of 171 m 2 /g. Further, although the phenomenon that the cerium oxide sol liquid (C1) contains a trace amount of cerium oxide is not used, it is derived from impurities. -19 - 201031463 (Comparative Example 2) The aluminum hydroxide molded article 122g obtained in the same manner as in Example 1 was sufficiently absorbed and mixed with cerium oxide sol ("SNOWTEX N" manufactured by Nissan Chemical Industries, Ltd.) 5.0 g and 25.2 g of cerium oxide sol solution of water were allowed to stand at room temperature for about 6 hours to dry, and then the obtained molded body was placed at 60 (TC was fired to obtain a catalyst (C2). Catalyst (C2) with alumina as the main component The medium contains 0.97 parts by weight of cerium oxide calculated as Si 〇 2 with respect to 100 parts by weight of alumina converted to A1203, and is oxidized to 1 〇〇 by weight of Al 2 〇 3 In other words, the catalyst (C2) has a BET specific surface area of 1 78 m 2 /g. The catalysts (1) to (4) obtained in the above examples and comparative examples are contained. And (C1) to (C2), the retention rate of catalyst activity (reaction rate) during continuous production of dimethyl ether, and the decrease rate of BET specific surface area under high temperature and high pressure water vapor atmosphere were evaluated by the following method. . The physical properties of each catalyst are shown in Table 1 together with the results. <Maintenance of Catalyst Activity> Each of the catalysts was used in a fixed bed flow reactor, and a methanol liquid (manufactured by Wako Pure Chemical Industries, Ltd.) was used under the conditions of a temperature of 2 90 ° C and a pressure of IMP aG. The special grade gasification is supplied at a space velocity (SV) of 20001 Γ1, whereby a methanol dehydration reaction is carried out to continuously produce dimethyl ether. The reaction rate of -20-201031463 after about 2 hours (initial) and after 7 days from the start of the reaction was obtained as follows. That is, after about 2 hours and after 7 days from the start of the reaction, 'sampling the outlet gas of the reaction apparatus, and determining the methanol concentration of the outlet gas OMeOH (mole concentration)', the methanol concentration of the inlet gas of the reactor is set to 100. %, from these methanol concentrations, the methanol reaction rate (%) at the initial stage and after 7 days was determined according to the following formula (1). The maintenance rate (%) of the reaction rate was calculated from the initial stage and the methanol reaction rate after 7 days according to the following formula (2), and the retention rate of the calculated reaction Φ rate was regarded as the continuous production of dimethyl ether. The retention of the activity of the catalyst was evaluated. Methanol reaction rate (%) = [(IMeOH-OMeOH) / IMeOH] xl 〇〇 (1) Maintenance rate (%) = [(Methanol reaction rate after 7 days) / (initial methanol reaction rate)] xlOO (2 <Degradation rate of BET specific surface area> In each of the catalysts, a high-pressure autoclave ("PCT-2〇0-l〇" manufactured by Nanben Chemical Co., Ltd.) was used in l5〇t, saturated steam. Handle for 24 hours. From the BET specific surface area before and after the treatment, the rate of decrease (%) was calculated according to the following formula (3), whereby the bet specific surface area decrease rate in a high-temperature high-pressure water vapor atmosphere was evaluated. Decrease rate (%) = [(BET specific surface area after treatment - BET specific surface area after treatment) / (BET specific surface area before treatment)] X100 (3) -21 - 201031463 [Table i] ※ Si02 content ※ Mg content The reaction rate BET is 7 days after the initial surface δ product. The retention rate after the treatment is reduced (parts by weight) (parts by weight) (%) (%) (%) (m2/g) (m2/g) (%) Example 1 0.91 0.16 78.3 73.5 93.9 177 121 31.8 Example 2 0.95 0.42 77.4 73.8 95.3 199 117 41.4 Example 3 1.02 0.57 74.7 72.3 96.8 184 103 44.2 Example 4 0.87 0.62 74.2 71.1 95.8 199 125 37.1 Comparative Example 1 0.03 0.00 78.3 70.9 90.5 171 51 70.5 Comparative Example 2 0.97 0.00 78.0 70.9 90.9 178 123 30.6 The content and the Mg content are expressed by parts by weight based on 100 parts by weight of the alumina converted to Al2〇3. As is clear from Table 1, in Examples 1 to 4 containing a magnesium element, the catalyst activity was maintained at a high rate, and even after 7 days, the methanol was subjected to a dehydration reaction at a high reaction rate. In the case of the comparative examples 1 and 2 catalysts containing no magnesium element, it is understood that the retention rate of the catalyst activity is low 'even if the initial reaction shows a high reaction rate, and if the reaction is supplied for a long time, the reaction rate is remarkable. reduce. @ In addition, when Comparative Example 1 is compared with Comparative Example 2, it is understood that when the content of cerium oxide is extremely small, the BET specific surface area of the catalyst is remarkably lowered by exposure to a high-temperature high-pressure water vapor atmosphere. From this phenomenon, it is understood that the catalyst of the present invention is supplied to the dehydration reaction in a high-temperature high-pressure water vapor atmosphere at a time of '100 parts by weight with respect to the alumina converted to A12〇3, and is contained in the conversion of si〇2. 0.5 part by weight or more of cerium oxide is suitable. -twenty two-