JP4063522B2 - Silica supported alkylation catalyst - Google Patents

Description

【００３４】
この上で述べたように、本発明に従い、シリカ結合剤ゼオライトベータ触媒を液相アルキル化で用いるに適するように設計する。本発明の実施では、アルキル化反応を、反応槽全体に亘って液相が維持されることを確保する目的で、用いる反応温度で芳香族基質が示す蒸気圧力より充分に高い圧力で実施する。完全な液相反応が生じるようにする目的で、触媒が液体中に完全に浸かるような溢れ床フォーマット（ｆｌｏｏｄｅｄ ｂｅｄ ｆｏｒｍａｔ）を用いる。これは、この上に示した実験研究で用いた如き上昇流技術を用いて容易に達成可能であり、これが一般に本発明の実施で用いるに好適であろう。しかしながら、触媒床が液状ベンゼンまたは他の芳香族基質で覆われることを確保するように出口流量を制御することにより、下降流溢れ床操作を達成することも可能である。
【００３５】
好適には、エチレン（または他のアルキル化剤）がベンゼン（または他の芳香族基質）中で示す良好な溶解度を確保しかつ反応全体が液相中で起こるようにする目的で、段階的反応フォーマット（ｓｔａｇｅｄ ｒｅａｃｔｉｏｎ ｆｏｒｍａｔ）を用いる。上述したＢｕｔｌｅｒの米国特許第５，０７３，６５３号に開示されているように、一連の逐次的に連結した反応槽を用い、単一の反応槽内に複数の触媒床を取り付けることにより、そのような段階的反応フォーマットを提供することができる。複数の段を設けると、断熱反応槽を用いた場合に段間冷却を行う機会を得ることができるか或は数段の等温反応段階を用いることが可能になる。ここで図３を参照し、エチレンとベンゼンの反応でエチルベンゼンを生産する時に用いられる段階的反応槽装置の図式図を示し、この装置には、段間冷却とエチレンの注入を伴う断熱反応槽が複数含まれている。より詳細には、この図に示すように、エチレンとベンゼンはライン１２と１４を経て脱水装置１６の入り口ライン１５に供給される。この脱水装置はアルキル化反応槽に投入される投入物（ｉｎｐｕｔ）に本質的な乾燥、望ましくは水含有量が１００ｐｐｍ未満、より好適には水含有量が５０ｐｐｍ未満になるように脱水する機能を果たす。例として、脱水装置１６は、乾燥剤、例えばシリカゲルまたは他の適切な吸湿性媒体が充填されている充填塔の形態または共沸乾燥塔（ａｚｅｏｔｒｏｐｉｃ ｄｒｙｉｎｇ ｃｏｌｕｍｎ）の形態を取っていてもよい。
【００３６】
前記脱水装置の流出液を反応槽１８、即ち上昇流様式で操作される複数の直列に連結したアルキル化反応槽の中の１番目の反応槽に供給する。反応槽１８を３５０℃以下の平均温度、好適には１５０−２５０℃の範囲内の平均温度で操作する。液相操作の場合、反応槽１８の圧力をベンゼンが液相中に保持されるに充分な圧力にし、好適にはベンゼンが反応槽温度で示す蒸気圧力より少なくとも５０ｐｓｉ高い圧力にする。この反応槽の圧力を典型的には約５００−８５０ｐｓｉａの範囲内にする。下流に位置する残りの反応槽も通常は前記１番目の反応槽の条件とほぼ同じ条件下で操作する。前記１番目の反応槽１８から出る流出液をライン１９を経て取り出して熱交換器２２に通して２番目の段階の反応槽２４に供給することにより、前記熱交換器２２によって前記２番目の段階の反応槽２４に送られる前の流出液を冷却しておく。エチレンをライン２１を経て供給し、これを１番目の反応槽１８から出て来る流出液と混合する。好適には、本図に示すように、エチレンが液状のベンゼンの全体に亘って分布することを助長する目的で、前記反応槽から出る流出液が冷却される前にエチレンを前記反応槽に送り込む。この冷却工程を、望ましくは、２番目の反応槽２４に供給される供給材料混合物の温度が前記１番目の反応槽１８の入り口温度の値とほぼ同じになるまで低くなるように実施する。通常、この２番目の反応槽の平均温度が前記１番目の反応槽の平均温度とほぼ同じになるようにする。この装置を通る流れを収容するに充分な圧力勾配が生じるようにする目的で、それの圧力の方がいくらか低くなるようにする必要がある。２番目の反応槽２４から出る流出液をライン２７を経て供給されるエチレンと共に２番目の段間冷却装置２９に送り込み、この冷却装置によって、３番目の反応槽３０への仕込み混合物を再び前記最初の２つの反応槽の入り口温度とほぼ等しい温度になるまで冷却する。
【００３７】
反応槽３０から出る生産物をライン３２を経て下流に位置する分離処理装置３４に送り込む。装置３４内でエチルベンゼンを分離してアルキル化プラントの生産物として取り出す。エチルベンゼンを、典型的には、スチレンの生産でエチルベンゼンが接触脱水素される脱水素装置への仕込み物として用いる。装置３４内で通常はベンゼンとエチレンを分離して、それらをアルキル化工程で再使用する。より重質のポリエチルベンゼンはベンゼンとアルキル交換を行い追加的にエチルベンゼンを生成させてもよい。アルキル交換装置と共に用いるに適した多段分離装置は、上述したヨーロッパ特許出願公開第４６７，００７号（これの開示は引用することによって全体が本明細書に組み入れられる）に開示されている一体式装置の中の１つの形態を取っていてもよい。モノアルキル化の選択率を向上させる目的で、アルキル化反応槽に送り込む仕込み原料に含めるベンゼンの量をエチレンに対して化学量論的過剰量にする。前記反応槽の操作を液相アルキル化が比較的穏やかな条件下で起こるように行うと、アルキル化反応で生成するキシレンの量が最小限になるばかりでなくまたベンゼン／エチレンのモル比を通常用いられるモル比よりいくらか低くすることも可能になる。通常用いるベンゼン／エチレンモル比は約４：１であるが、約２：１の如き低いモル比を用いることも可能になる。しかしながら、極端に高い比率を用いる動機は一般にほとんどなく、実用事項として、ベンゼン／エチレンのモル比が１５：１を越えることはほとんどないであろう。好適なベンゼン／エチレンモル比は約４／１である。この上に示したベンゼン／エチレンモル比は装置全体および多段反応装置、例えば本図に示した如き装置に関するモル比であり、各段に供給する供給材料のベンゼン／エチレン比は前記全体比より小さいであろう。各反応槽段に供給されるベンゼン仕込み物に溶解するエチレンの量は、用いる反応槽段の数に部分的に依存するであろう。通常は、示すように、少なくとも３段の反応槽段が用いられるであろう。追加的反応槽段を設ける場合でも通常は全段数が８を超えることはないであろう。各反応段の圧力および各反応段に供給されるエチレンの量を、好適には、エチレンがベンゼンに少なくとも１モルパーセント溶解するような圧力および量にする。通常、エチレンが各反応槽に供給される仕込み物に少なくとも２モルパーセント溶解する。多大な数で反応槽段を用いない限り、各反応槽のベンゼン液相に溶解するエチレンの量は一般に少なくとも４モルパーセントになる。
【００３８】
また、本発明に従い、等温反応ゾーン（ｉｓｏｔｈｅｒｍａｌ ｒｅａｃｔｉｏｎ ｚｏｎｅｓ）を用いてベンゼンの多段エチル化を実施することも可能である。等温反応槽は殻と管の種類の熱交換器の形態を取っていてもよく、この場合、アルキル化用触媒を管内に配置しそして伝熱媒体を前記触媒を充填した管の回りに位置する殻に通して循環させてもよい。勿論、熱交換器用媒体を温度が各反応段に亘って比較的一定に維持されるような供給速度で反応槽に通して供給する。この場合には段間冷却を行う必要はないであろうが、エチレンを各反応段の前方に注入するのが好適であろう。
【００３９】
この上に示したように、前記ベータ−シリカ触媒（ｂｅｔａ−ｓｉｌｉｃａ ｃａｔａｌｙｓｔ）を比較的穏やかな条件下の液相アルキル化反応で用いるのが好適である。しかしながら、本発明を、ベンゼン基質を温度と圧力の両方がベンゼンの臨界温度および臨界圧力より高い苛酷な条件下で用いることで操作を超臨界範囲内で行う（それによってアルキル化反応槽を準液相で操作する）ことで実施することも可能である。この上に示したように、その場合には、アルキル化反応槽を約２９０℃以上の温度および７００ｐｓｉａを超える圧力で操作することになるであろう。通常は、いくらか高い温度およびいくらか高い圧力が用いられるであろう。ここで、ベンゼンを超臨界範囲内で用いたアルキル化反応槽の操作は３００−６００℃の範囲および約６５０−８５０ｐｓｉａの範囲内になるであろう。
【００４０】
本発明の具体的態様を記述して来たが、それの修飾形が本分野の技術者に思い浮かぶ可能性があることで添付請求の範囲の範囲内に入る如きそのような修飾形の全部を保護することを意図することは理解されるであろう。
【００４１】
本発明の特徴および態様は以下のとおりである。
【００４２】
１．
（ａ）ベンゼン含有原料を反応ゾーンに供給しそしてそれをシリカ結合剤と共に配合されていて再生を５００℃以下の温度で少なくとも３回実施した時に少なくとも９５％の平均再生係数を示すアルキル化用ゼオライトベータ触媒を含んで成るモレキュラーシーブ触媒に接触させ、
（ｂ）Ｃ₂−Ｃ₄アルキル化剤を前記反応ゾーンに供給し、
（ｃ）前記反応ゾーンを前記アルキル化剤による前記ベンゼンのアルキル化が液相中または超臨界範囲内でもたらされるに有効な温度および圧力条件下で操作し、そして
（ｄ）アルキル化ベンゼンを前記反応ゾーンから回収する、
ことを含んで成る芳香族アルキル化方法。
【００４３】
２． 前記アルキル化剤がエチル化剤である第１項記載の方法。
【００４４】
３． 前記エチル化剤がエチレンである第２項記載の方法。
【００４５】
４． 前記反応ゾーンを前記ベンゼンが液相中に存在する温度および圧力条件下で操作する第１項記載の方法。
【００４６】
５． 前記ベンゼンおよびアルキル化剤を前記反応ゾーンに前記アルキル化剤に対するベンゼンのモル比が１５未満であるような流量で供給する第４項記載の方法。
【００４７】
６． 前記アルキル化剤に対する前記ベンゼンのモル比を１０未満にする第５項記載の方法。
【００４８】
７． 前記アルキル化剤に対するベンゼンのモル比を４−１０の範囲内にする第５項記載の方法。
【００４９】
８．
（ａ）ベンゼン含有原料を反応ゾーンに供給しそしてそれをシリカ結合剤と共に配合されているアルキル化用ゼオライトベータ触媒を含んで成るモレキュラーシーブ触媒に接触させ、
（ｂ）エチレンを前記反応ゾーンに供給し、
（ｃ）前記反応ゾーンをベンゼンが液相中または超臨界相中に存在していて前記ベンゼンのエチル化が一次活性時の前記アルキル化用触媒の存在下で起こる温度および圧力条件下で操作し、
（ｄ）エチルベンゼンを含有するアルキル化生成物を前記反応ゾーンから回収し、
（ｅ）前記反応ゾーンの操作を前記触媒がベンゼンのエチル化に関して示す活性が前記触媒がベンゼンのエチル化に関して示す前記一次活性から０．１％の値だけ低下するまで継続し、
（ｆ）ベンゼンのアルキル化に関する前記反応ゾーンの操作を停止しそして前記触媒の再生を酸化環境下で再生工程過程中の平均温度が５００℃以下であるように行う再生手順を設け、
（ｇ）前記再生手順の後に、ベンゼンを前記アルキル化反応ゾーンに供給することによって前記アルキル化反応ゾーンの操作を再び設け、
（ｈ）前記反応ゾーンを前記ベンゼンのエチル化が前記再生触媒の存在下で前記一次活性の少なくとも９５％の二次活性で起こってエチルベンゼンが生成するように前記ベンゼンのエチル化が液相中または超臨界相中で起こるに有効な温度および圧力条件下で操作し、
（ｉ）前記アルキル化反応ゾーンの操作を前記触媒がベンゼンのエチル化に関して示す活性が前記二次活性の少なくとも０．１％の度合で降下するまで継続し、
（ｊ）前記アルキル化反応ゾーンの操作を停止しそして前記触媒に再生を酸化環境下において５００℃以下の平均温度で行うことにより前記触媒の再生を実施し、
（ｋ）ベンゼンおよびエチレンを前記アルキル化反応ゾーンに供給し、そして
（ｌ）前記反応ゾーンを前記ベンゼンのエチル化が前記再生触媒の存在下でベンゼンのエチル化に関する初期活性が前記二次活性の少なくとも９５％を与えるように前記ベンゼンのエチル化が液相中または超臨界相中で起こるに有効な温度および圧力条件下で操作する、
ことを含んで成るエチルベンゼンの製造方法。
【００５０】
９． 前記ゼオライトベータ触媒がゼオライトベータの中にランタンイオンをイオン交換で組み込ませられたランタンにより変性されたゼオライトベータを含んでなる第８項記載の方法。
【００５１】
１０． 前記ゼオライトベータが少なくとも４０のシリカ／アルミニウム比を有する第８項記載の方法。
【００５２】
１１． 前記ゼオライトベータ触媒がゼオライトベータの結晶構造内に内部成長のＺＳＭ−１２結晶骨組を有する変性ゼオライトベータを含んでなる第８項記載の方法。
【００５３】
１２． 前記ゼオライトベータが少なくとも３回の再生後に示す再生係数がアルミナ結合剤を前記ゼオライトベータと共に用いられるシリカ結合剤の量と同じ量で用いて配合されたゼオライトベータ触媒が示す再生係数の値の少なくとも１０５％である第８項記載の方法。
【００５４】
１３． 前記反応ゾーンを前記ベンゼンが液相中に存在する温度および圧力条件下で操作する第８項記載の方法。
【００５５】
１４． 前記ベンゼンおよびアルキル化剤を前記反応ゾーンに前記アルキル化剤に対するベンゼンのモル比が１５未満であるような流量で供給する第１３項記載の方法。
【００５６】
１５． 前記アルキル化剤に対する前記ベンゼンのモル比が１０未満である第１４項記載の方法。
【００５７】
１６． 前記アルキル化剤に対するベンゼンのモル比が４−１０の範囲内である第１４項記載の方法。
【図面の簡単な説明】
【図１】図１は、アルミナ結合剤と共に配合されたゼオライトベータ触媒を用いた液相アルキル化条件下で最も高い温度の時の触媒床の体積パーセントを示すグラフである。
【図２】図２は、シリカ結合剤と共に配合した再生ゼオライトベータ触媒を用いてベンゼン／エチレンのモル比を累進的に減少させた時の累進的液相条件下で最に高いアルキル化温度の時の触媒床の体積パーセントを示すグラフである。
【図３】図３は、本発明の実施で使用可能な段階的反応槽装置の図式図である。[0001]
Field of the Invention
The present invention relates to an aromatic alkylation involving the alkylation of an aromatic substrate, such as benzene, using a zeolite beta catalyst for aromatic alkylation formulated with a silica binder. aromatic alkylation) method.
[0002]
BACKGROUND OF THE INVENTION
Zeolite beta is a well-known molecular sieve catalyst used in hydrocarbon conversion processes such as dewaxing and catalytic cracking of relatively heavy high molecular weight hydrocarbon oils. Zeolite beta, as used in carrying out such a conversion, was first disclosed in US Pat. No. 3,308,069 to Waddinger et al. And later disclosed in so-called improvements in US Pat. No. 4,642,226 to Calvert et al. It was done. As disclosed in the Calvert patent, conversion processes in which zeolite beta is particularly useful include inter alia dewaxing, hydroisomerization, cracking, hydrocracking and aromatization (light aliphatic hydrocarbons). By conversion to aromatic hydrocarbons). As disclosed by Calvert, the preparation of zeolite beta used in such a conversion process involves the preparation of silica and alumina, and optionally various other metal oxides or hydroxides, and an organic templating agent (which is desired). It can be carried out using a synthetic procedure involving hydrothermal digestion of the reaction mixture containing (used for the purpose of generating a crystal structure). The amount of silica and alumina in the reaction mixture can vary in the molar ratio of silica to alumina in the range of 20-250, so that the final silica / alumina molar ratio of the crystalline product is less than 20 to about 60 and Calvert can range as high as 171 in the example shown.
[0003]
A variety of other molecular sieves, as well as molecular sieve catalysts such as zeolite beta, are usually used in combination with a matrix material [which serves as a binder for the molecular sieve]. For example, the Waddinger patent mentioned above discloses that zeolite beta can be used alone or as a dispersed mixture in combination with a low activity and / or catalytically active material (acting as a binder for the zeolite catalyst component). ing. The above-mentioned Calvert patent discloses the use of inorganic materials such as clay, silica or alumina, or various composite materials such as silica / alumina, silica / magnesia, and various other two-component and three-component compositions. Has been.
[0004]
In addition to being used in hydrocarbon conversion processes [eg, including dewaxing, hydrocracking or aliphatic aromatic conversion as described above], zeolite beta is not only used in zeolite beta, but also other A variety of molecular sieves have also been used as catalysts in the alkylation of aromatic substrates. Such an alkylation conversion reaction involves the alkylation of an aromatic substrate, such as benzene, to produce an alkyl aromatic, such as ethylbenzene, ethyltoluene, cumene, or higher aromatics, followed by transalkylation of the polyalkylbenzene. The production of monoalkylbenzene. Typically, an alkylation reactor that provides a mixture of monoalkylbenzene and polyalkylbenzene may be coupled to a downstream alkyl exchange reactor through various separation stages. Such alkylation and alkyl exchange reactions can be carried out in the liquid phase, in the gas phase, or under conditions in which both the liquid phase and the gas phase are present.
[0005]
US Pat. No. 4,185,040 to Ward et al. Has a low sodium content, ie Na ₂ An alkylation process using a molecular sieve catalyst having an O content of less than 0.5% by weight is disclosed, which catalyst is particularly useful when producing ethylbenzene from benzene and ethylene and cumene from benzene and propylene. Is said to be useful for use in manufacturing. Examples of suitable zeolites include X, Y, L, B, ZSM-5, and omega crystalline molecular sieves, and steam stabilized hydrogen Y zeolite is preferred. Specifically, Na ₂ Ammonia Y zeolite containing about 0.2% O is stabilized with steam. The Ward et al. Patent discloses various catalyst configurations. Cylindrical extrudates can also be used, but a particularly preferred catalyst shape is the so-called “trilobal” shape, which somewhat resembles a trilobal clover. The extruded product has a surface area / volume ratio of 85-160 inches. ^-1 Must be within the range. The alkylation step can be carried out in either upward or downward flow, the latter being preferred, and preferably at least until substantially all of the alkylating agent olefin has been consumed. It can be performed under temperature and pressure conditions such that at least some phase is present. The Ward et al patent states that catalyst deactivation occurs rapidly under most alkylation conditions if no liquid phase is present. In the various conversion methods described above as well as the Ward method, the zeolite may be mixed with a porous mineral oxide binder for the purpose of reaching a granular catalyst form, such as a trilobal form. . Thus, Ward discloses the use of alumina gel, silica gel, silica / alumina co-gel, various clays, titania and other mineral oxides in combination with a suitable zeolite-Y, with alumina being preferred. It is disclosed.
[0006]
As with the use of zeolites in conversion or alkylation processes, procedures involving the use of zeolite beta in alkylation or transalkylation processes are usually performed using alumina as a binder to provide a matrix for the zeolite catalyst. Is done. Thus, US Patent No. 4,891,458 to Ennes et al. Discloses a liquid phase alkylation or transalkylation process for aromatic hydrocarbons using zeolite beta catalysts. The atomic ratio of silicon to aluminum contained in the zeolite beta disclosed by Ennes et al. Is from 5: 1 to less than 100: 1, preferably from 5: 1 to less than 50: 1. Ennes discloses that alkylation is carried out under conditions where the molar ratio of aromatic to olefin is at least 4: 1 in order to prevent the catalyst from becoming fouled rapidly. The reaction temperature is in the range of about 100 to 600 degrees F and the reaction pressure is typically about 50-100 psig, which is sufficient temperature and pressure to at least partially maintain the liquid phase. Zeolite beta suitably used in the Ennes process is mainly in the hydrogen form, which is achieved by calcination following ammonia exchange of the synthesized product. Ennes discloses that high purity zeolites may be used with inorganic oxide binders such as alumina, silica, silica / alumina or naturally occurring clays. Ennes continues to state that the preferred inorganic binder is alumina.
[0007]
Ratcliffe et al., U.S. Pat. No. 4,798,816, discloses another alkylation method which treats in a manner that improves selectivity to monoalkylation, particularly propylation of benzene to form cumene. With the use of a modified molecular sieve catalyst for alkylation. When carbon-based material is first deposited on the catalyst and then burned to the resulting carbon-containing catalyst particles, the selectivity is improved by at least 1 percentage point. Specific crystalline zeolitic molecular sieves include molecular sieves selected from the group of Y zeolites, fluorinated Y zeolites, X zeolites, zeolite beta, zeolite L and zeolite omega. A suitable Y-type zeolite can be dealuminated so that the ratio of total silica to alumina is greater than 6. As in the previous literature, a suitable refractory inorganic oxide material for use as a binder is alumina, in particular catapal, but other binders such as alumina, gallia, thalia, titania, zirconia, Beryllia, silica, silica-alumina and various other materials are also disclosed.
[0008]
Butler European Patent Application Publication No. 467,007 discloses another method in which an alkylation zone and an alkyl exchange zone exist separately, in which various molecular sieve catalysts are used, Product exiting the reactor is recycled to the intermediate separation zone. There, a benzene separation zone is located in front of the preliminary fractionation zone, the ethylbenzene / polyethylbenzene fraction is recovered from the remainder of the zone and the top benzene fraction is recycled to the alkylation reactor. Yes. In the preliminary fractionation zone, the overhead benzene fraction (which is recycled with the overhead coming from the benzene tower) and the kettle residue (which contains benzene, ethylbenzene and polyethylbenzene) Produces. The subsequent two separation zones are positioned between the benzene separation zone and the transalkylation reactor to recover ethylbenzene as a process product and a heavy residue fraction. The polyethylbenzene distillate exiting from the last separation zone is sent to the transalkylation reactor and the product obtained there is sent directly to the second benzene separation column or indirectly to the second benzene separation column via a separation device. Send it in. Butler operates the alkylation reactor in the liquid phase using a catalyst such as zeolite-beta, zeolite-Y or zeolite-omega, or gas phase using a catalyst such as silicalite or ZSM-5. Discloses what can be done in it.
[0009]
Another method involving liquid phase alkylation of aromatic substrates is disclosed in Shamshou et al., European Patent Application Publication No. 507,761. This process involves the use of a molecular sieve catalyst based on zeolite beta but modified by incorporating lanthanum. Shamshoum et al. Show that little or no xylene is produced under mild liquid phase alkylation conditions when using lanthanum-modified zeolite beta catalysts as opposed to using hydrogen form of zeolite beta. Disclosure. In the method of Shamshoum et al., The silica / alumina ratio of the initial zeolite beta is preferably in the range of 20 to 50, which is first calcined at a temperature of about 570 ° C. for 2 hours or more after an ion exchange step. Yes. The molecular sieve after the ion exchange and calcination steps is dried and then subjected to ion exchange with a lanthanum salt solution to incorporate lanthanum into the zeolite system. Shamshoum et al. Disclosed mixing such lanthanum beta zeolite with a binder such as alumina sol, gamma alumina or other refractory oxides to form a mixture of zeolite and binder and then pelletized. .
[0010]
Other methods involving liquid phase alkylation of benzene are disclosed in US Pat. No. 5,030,786 to Shamshouum et al. And 5,073,653 to Butler. Shamshou '786 discloses the use of molecular sieves having a pore size greater than 6.5 angstroms, particularly zeolite Y and zeolite beta having pore sizes in the range of 7-7.5 angstroms. The Butler patent discloses the alkylation of benzene in the liquid phase using catalysts including zeolites such as zeolite omega, zeolite beta and zeolite Y. Butler can reduce the molar ratio of benzene to ethylene used in the reactor if the alkylation reactor is operated under relatively mild liquid phase conditions, and is less than about 5: 1, preferably It is disclosed that the molar ratio can range from 4: 1 or less to about 2: 1. Also disclosed is the higher ratio of 15: 1. Butler specifically discloses a catalyst having a crystalline zeolite omega content of 80% and an alumina binder content of 20% by weight.
[0011]
SUMMARY OF THE INVENTION
According to the present invention, there is provided an aromatic alkylation method for alkylating a benzene-containing raw material using a zeolite beta catalyst for alkylation. This alkylating zeolite beta catalyst is formulated with a silica binder, which has an average regeneration coefficient of at least 95% for at least 3 regenerations. This alkylation reaction is a C ₂ -C _Four It is carried out in the liquid phase or in the supercritical range using an alkylating agent. In a preferred embodiment of the present invention, the alkylating agent is an ethylating agent, more specifically ethylene. The catalyst exhibits a regeneration factor of at least 95% after ethylation of benzene with ethylene with a benzene / ethylene molar ratio of less than 10.
[0012]
In a further aspect of the invention, the benzene-containing feed is fed to a reaction zone containing a molecular sieve catalyst comprising an alkylating zeolite beta catalyst blended with a silica binder. Ethylene is fed to the reaction zone and the reaction zone is operated under temperature and pressure conditions where benzene is present in the liquid phase or in the supercritical phase. The ethylation of benzene occurs with an initial designated primary activity. This reaction zone operation is continued until the activity exhibited by the catalyst with respect to ethylation of benzene has decreased by a value of at least 0.1% from the initial designated primary activity. It should be ensured that the value that declines from the initial designated primary activity does not exceed 1%. The operation of this alkylation reaction is stopped and a regeneration step is provided. In this regeneration step, the catalyst is regenerated at an average temperature of 500 ° C. or less in an oxidizing environment. At the end of this regeneration step, the alkylation zone operation is resumed and the reaction zone is again operated under temperature and pressure conditions effective for benzene ethylation to occur in the liquid or critical phase. The initial activity that this catalyst exhibits in such a second pass is such that it provides a secondary activity of at least 95% of said initial primary activity. The operation of the alkylation reaction zone is continued until the activity of the catalyst drops to a degree that is at least 0.1% of the initial secondary activity, and then the operation of the alkylation reaction zone is stopped again and the catalyst is The regeneration process as described above is applied. At the end of this regeneration step, benzene and ethylene are again fed to the alkylation reaction zone. This alkylation zone is operated at temperatures and pressures where benzene is present in the liquid phase or supercritical phase and the additional tertiary activity for ethylation of benzene gives at least 95% of said secondary activity.
[0013]
Detailed Description of the Invention
The present invention provides for the alkylation of aromatic substrates (including benzene), preferably under relatively mild liquid phase alkylation conditions, in a reaction zone containing an alkylating zeolite beta catalyst. The present invention is particularly applicable when the ethylation of benzene is carried out under mild liquid phase conditions where no or little xylene is formed, and the present invention will be described with particular reference to the production of ethylbenzene. However, other alkylation reactions can be used in the practice of the present invention. For example, the present invention is applicable to a reaction in which propene and benzene are reacted to produce cumene. Also, olefinic alkylating agents are usually used, but other alkylating agents such as those disclosed in US Pat. No. 3,551,510 to Pollitzer et al., For example, alkynes, alkyl halides, alcohols Ethers and esters can also be used.
[0014]
As noted above, the alkylation reactor is preferably operated under relatively mild pressure and temperature conditions where benzene is present in the liquid phase, i.e. at a temperature well below the critical temperature of benzene and benzene in the liquid phase. Operating under sufficient pressure to be held in However, it is also possible to carry out this alkylation reaction under conditions in which benzene is present in the supercritical phase, i.e. above the critical temperature and pressure, and in this connection, unless otherwise specified. It will be understood that the term “liquid phase” or “liquid phase reaction” as used herein represents operations within the liquid region as well as operations within the supercritical range.
[0015]
The zeolite beta used in the present invention may be a normal zeolite beta, or any one of a variety of modified zeolite betas described in more detail below. In the present invention, regardless of the nature of such zeolite beta, the process proceeds in contrast to conventional methods where zeolite beta is usually combined with an alumina binder such as gamma alumina or catapal alumina. Thus, as described in more detail below, when zeolite beta is used in the present invention, it is formulated with a silica binder, resulting in a zeolite beta catalyst suitable for use in liquid phase alkylation, thus silica. Zeolite beta formulated with a binder exhibits substantially better deactivation and regeneration properties compared to zeolite beta formulated with conventional alumina binders. The regeneration characteristics exhibited by zeolite beta formulated with this silica binder after at least three regenerations are as follows, using an alumina binder in the same amount as the silica binder used in the present catalyst, as described below. And at least 105% of the regeneration coefficient exhibited by the zeolite beta catalyst blended with each other.
[0016]
The zeolite beta used in the present invention may be zeolite beta with a high silica / alumina ratio, lanthanum modified zeolite beta, or zeolite beta modified with ZSM-12 as described in detail below. Of course, this may also be a more or less conventional zeolite beta as disclosed, for example, in the aforementioned Waddinger et al. Patent 3,308,069 and Calvert et al. Patent 4,642,226. . Regardless of the nature of such zeolite beta, blending it with a silica binder results in a substantially more stable catalyst than zeolite beta blended with an alumina binder in the traditional manner. In addition, the zeolite beta-silica bonded catalyst of the present invention is stable even when the benzene / ethylene ratio is substantially lower compared to the corresponding zeolite beta catalyst formulated with an alumina binder.
[0017]
Zeolite beta is a well-known molecular sieve catalyst as described above, and its basic preparation method is well known to those skilled in the art. Methods for preparing crystalline zeolite beta are described above in US Pat. No. 3,308,069 to Wadlinger et al., US Pat. No. 4,642,226 to Calvert et al., And European Patent Application Publication No. 159,846 to Reuben Is hereby incorporated by reference in its entirety]. The zeolite beta has a low sodium content, i.e. Na. ₂ It can be prepared to be less than 0.2% by weight expressed as O, and further, by performing ion exchange treatment on it, the sodium content can be further reduced to a value of about 0.02% by weight. It is.
[0018]
As disclosed in the Waddinger et al. And Calvert et al. Patents cited above, zeolite beta contains silica and alumina and sodium or other alkyl metal oxides and an organic templating agent. It is also possible to produce the reaction mixture by performing hydrothermal digestion. Typical cooking conditions include temperatures ranging from slightly lower than the boiling point of water at atmospheric pressure to about 170 ° C. at a pressure equal to or higher than the vapor pressure exhibited by water at the temperature used. Is included. By gently stirring the reaction mixture for a period ranging from about 1 day to several months, the degree of crystallization desired for the production of zeolite beta is achieved. The resulting zeolite beta is usually a silica to alumina molar ratio (SiO ₂ / Al ₂ O _Three In the range of about 20 to 50.
[0019]
Next, the zeolite beta undergoes ion exchange with ammonium ions, but this ion exchange is carried out without adjusting the pH. It is preferred to use an aqueous solution of an inorganic ammonium salt such as ammonium nitrate as the ion exchange medium. Following this ammonium ion exchange treatment, the zeolite beta is filtered, washed and dried, and then calcined at a temperature of about 530 ° C. to 580 ° C. for a period of 2 hours or more.
[0020]
Zeolite beta can be characterized by its crystal structure symmetry and x-ray diffraction pattern. Zeolite beta is a molecular sieve with a medium or about 5-6 angstrom pore size and contains a 12-ring channel systems. Zeolite beta is square symmetric P4 ₁ 22, a = 12.7, c = 26.4２６ (WM Meier and DH Olson Butterworth, “Atlas of Zeolite Structure Types”, Heinemann, 1992, p. 58), ZSM-12 It is generally characterized by monoclinic symmetry. Zeolite beta pores are generally circular with a diameter of about 5.5 angstroms along the 001 plane and elliptical with diameters of about 6.5 angstroms and 7.6 angstroms along the 100 plane. Zeolite beta is described in more detail by Higgins et al. In "The framework to topology of zeolite beta", Zeolites, 1988, Vol. 8, November, pages 446-452, the disclosure of which is incorporated herein by reference in its entirety. Has been.
[0021]
The zeolite beta blend used in the practice of the present invention may be a conventional zeolite beta based blend as disclosed in the above-mentioned Calvert et al. Patent or disclosed in the above mentioned SHA publication by Shamshou et al. Formulations based on lanthanum modified zeolite beta such as those described above, or intergrowth of ZSM-12 crystals as disclosed in Ghosh et al. US Pat. No. 5,907,073. It may be a modified zeolite beta. However, rather than using an alumina binder as disclosed by Ghosh, a silica binder as disclosed herein is used. For further description of methods of producing zeolite beta useful for use in accordance with the present invention, see Waddinger, Patent No. 3,308,069, Calvert, 4,642,226 and Ghosh, 5,907,073 and Reference is made to Shamshou, EP 507,761, the disclosures of which are hereby incorporated by reference in their entirety.
[0022]
It is also possible to practice the present invention using silica-bound zeolite beta based on zeolite beta, which has a higher silica / alumina ratio than is normally found. For example, as disclosed in Kennedy European Patent Application Publication No. 186,447, it is possible to increase the silica / alumina ratio of the zeolite by subjecting the calcined zeolite beta to dealumination by steam treatment. is there. Therefore, as disclosed by Kennedy, steam treatment using 100% steam on calcined zeolite beta having a silica / alumina ratio of 30: 1 was performed at 650 ° C. under atmospheric pressure for 24 hours. The result was a catalyst with a silica / alumina ratio of about 228: 1, followed by an acid wash step to produce 250: 1 zeolite beta. Aluminum can be removed from the framework of zeolite beta by subjecting various zeolite betas to extraction treatment using nitric acid. When acid washing of the zeolite beta is first performed, a zeolite beta with a high silica / alumina ratio is achieved. Thereafter, lanthanum is introduced into the zeolite framework by ion exchange. A subsequent acid wash should not be performed so that lanthanum is not removed from the zeolite.
[0023]
In the aromatic alkylation process, it is highly desirable to regenerate the catalyst after the activity of the catalyst decreases over time during the alkylation process. In experimental studies conducted in connection with the present invention, the regenerative nature of zeolite beta blended with a silica binder is substantially better than that of zeolite beta blended with an alumina binder in accordance with conventional procedures of conventional techniques. I found something. The activity of fresh catalysts during the alkylation process is typically relatively higher in the initial stage, and this activity can be measured in percent of ethylbenzene produced at the specified benzene / ethylene molar ratio and benzene space velocity. is there. While it is desirable for the activity during the initial period to be relatively constant, the activity of the catalyst gradually decreases due to coking of the catalyst at some point during the alkylation process. After the activity of the catalyst has fallen to the point where further operations cannot be performed or at least not economically feasible, the reactor may be removed from the flow and the catalyst regenerated. A typical regeneration step is to first add nitrogen and then add air to the nitrogen and gradually increase the amount of air to reach the desired oxygen content. For example, the initial oxygen content may be about 0.5% by volume, and such a regeneration gas may be injected at a temperature of about 500 ° C. As the oxygen content is gradually increased, coke is burned out of the catalyst and eventually the catalyst reaches a regenerated state, the activity of which is close to or equal to the initial catalyst activity. There is even a thing. In the regeneration of zeolite beta, it is desirable to supply a nitrogen atmosphere at a temperature close to 500 ° C. before introducing oxygen for the purpose of initially expelling substantially all of the hydrogen from the catalyst so as not to generate water.
[0024]
The regeneration of the catalyst can be characterized by the regeneration factor, which indicates the level at which the catalyst can be regenerated when moving from one alkylation pass to another (this is the catalyst). Comparison under conditions of initial activity shown). Thus, taking into account multiple alkylation passes and regeneration passes, the catalyst exhibits 10% ethylbenzene under standard conditions in the first pass and the first regeneration step. Assuming that the activity of the catalyst under the same conditions at the beginning of the second alkylation pass at the end of is 9% ethylbenzene, the regeneration factor in this case will be characterized as 90%. If the same regeneration coefficient is observed when the second pass is transferred to the third alkylation pass with the second regeneration, the initial activity at the start of the third pass is 8. It will be 1% ethylbenzene.
[0025]
In the description of the present invention, the term “regeneration coefficient” is characterized in the meaning of the following standard conditions. The catalyst is used in a liquid phase alkylation step carried out at a temperature and pressure of 300 ° C. and 650 psig so that the benzene / ethylene molar ratio is 10. The ethylation reaction is carried out until the activity of the catalyst is reduced by 0.5 percent as measured by percent ethylene conversion. Next, nitrogen is first injected at a temperature of 500 ° C. for 24 hours, and then the catalyst is regenerated by slowly increasing the oxygen content of nitrogen to 10% oxygen over 24 hours. Next, when the catalyst reaches the secondary alkylation activity in the second alkylation pass, the initial activity is measured, and the regeneration coefficient is measured using the initial activity.
[0026]
In an experimental study relating to the present invention, alkylation was carried out using lanthanum beta zeolite (catalyst A) blended with an alumina binder and lanthanum beta zeolite (catalyst B) blended with a silica binder. The lanthanum beta zeolite was prepared according to the method of EPO 507761, which had a silica / alumina ratio of about 100 and a lanthanum content of about 1% by weight. This experimental study was conducted using a single pass reactor having a temperature of 300 ° C. and a pressure of 650 psig. The purity of the benzene feed is about 99%, which is 70 hours ^-1 Of space velocity (LHSV). Two sets of tests were performed, i.e. 5 ml of catalyst was used in the catalyst bed in one test and 10 ml of catalyst was used in the catalyst bed in the other test.
[0027]
In the first set of tests conducted with Catalyst A (lanthanum beta compounded with alumina binder), the temperature of the catalyst bed was measured as a function of time in two successive passes (with the regeneration step interposed). One set of tests was performed with a 5 ml bed of catalyst and the other set of activities with a 10 ml bed of activity.
[0028]
The alkylation experiment is conducted for 5 days when the catalyst is a 5 ml bed and for 4 days when the catalyst is a 10 ml bed, and the temperature is measured with a thermocouple spaced along the bed. Detected. The results of the first screening test carried out with catalyst A are shown in FIG. 1, which plots the volume percent (V) of the bed on the vertical axis when the temperature is maximum (490 ° C.). The test time [day (D)] plotted on the horizontal axis was compared. Curve 2 in FIG. 1 shows the result of the first pass with a 5 ml bed and curve 3 shows the result of the second pass with a 5 ml bed. Curves 5 and 6 show the results of the first and second pass through a 10 ml bed, respectively. The temperature during regeneration was adjusted so that the maximum value was 490 ° C. In both the 5 ml bed experiment and the 10 ml bed experiment, the deactivation rate that lanthanum beta exhibited after the first regeneration was faster than the initially observed deactivation rate. Furthermore, no activity is restored after the second regeneration, indicating that the lanthanum beta zeolite formulated with the alumina binder is not stable enough to withstand multiple regenerations.
[0029]
In the second set of experiments, the experiment was conducted using critical lanthanum beta conditions with lanthanum beta blended with a 20% amount of silica binder, which is approximately the same amount of binder used in the lanthanum beta alumina catalyst composition. Conducted below. Here, the alkylation experiment was carried out at a temperature higher than the critical temperature of benzene (289 ° C.). The reactor temperature was 300 ° C., the pressure was 650 psig, and the benzene space velocity (LHSV) was 70 hours. ^-1 I made it. This catalyst was confirmed to be stable when the benzene / ethylene molar ratio was 10: 1. At the end of the initial experiment conducted over 4 days, the catalyst was regenerated using the following regeneration process:
1. Cool to ambient temperature with a minimum benzene flow rate;
2. Starting a purge with 240 sccm of nitrogen to maintain the reactor in downflow mode;
3. Increase the temperature to 400 ° C. at a rate of less than 100 ° C. per hour and hold for 3 hours;
4). Cooling to 250 ° C .;
5. Slowly add air at the minimum mass flow controller speed to prevent exotherm from exceeding 490 ° C;
6). At the end of the initial rapid combustion, nitrogen is reduced to 0 sccm while air is slowly increased to 240 sccm over 2 hours;
7). Raise the temperature to 485 ° C. and hold for 3 hours; and
8). Cool to ambient temperature with air flow.
[0030]
Next, the space velocity of benzene is set to 70 hours using the regenerated catalyst. ^-1 The second pass experiment was carried out while maintaining the space velocity of the reactor, and the ethylene feed rate was gradually increased over time to achieve benzene / ethylene ratios of 20: 1, 10: 1 and 7.9: 1. I made it. The results of this experimental study are shown in FIG. 2, in which the catalyst bed operation is plotted with the volume percent (V) of the bed at the maximum (490 ° C.) on the vertical axis and plotted on the horizontal axis. Time [day (D)] was compared. Curve 8 in FIG. 2 shows the data for a benzene / ethylene molar ratio of 20: 1, and curve 9 shows the data for a benzene / ethylene molar ratio of 9: 1. 10 shows data when the molar ratio of benzene / ethylene is 7.9: 1. As can be seen by examining the data shown in FIG. 2, the catalyst is clearly completely stable when the benzene / ethylene molar ratio is 10: 1 and 7.9: 1, and the molar ratio is Even higher and 20: 1, the stability it showed was substantially better than the stability exhibited when the alumina binder catalyst had a benzene / ethylene ratio of 10: 1. Met. On day 10, the benzene space velocity is lowered and the ethylene flow rate is further lowered to a benzene / ethylene ratio of about 3: 5, at which point the catalyst is soon deactivated, as curve 11 shows. Began to show.
[0031]
In further experimental studies, lanthanum beta zeolite (catalyst B) formulated with silica binder was used, with a benzene / ethylene molar ratio of 20: 1 and 10: 1, in four consecutive passes (with regeneration). Experiments were performed. This experimental study was performed using a lanthanum beta with a silica / alumina ratio of 50: 1. The temperature is controlled to a maximum value of 490 ° C., the pressure is 650 psig to operate within the critical range, and the reaction conditions are more severe than the mild temperature and pressure conditions used in normal liquid phase alkylation. did. Benzene supply speed is 70 hours for each pass ^-1 Of LHSV. Between each pass, the catalyst was regenerated in the same regeneration step as described above.
[0032]
The results of this experimental study are listed in Table 1. As shown in Table 1, the EB content of each pass, the percentage of diethylbenzene as measured against the ethylbenzene present in the production stream, the amount of butylbenzene based on the ethylbenzene content [ppm (parts per million) And the amount (ppm) of propylbenzene based on ethylbenzene contained in the product. As can be seen by examining Table 1, the catalyst maintained good activity after each regeneration, and the activity during the fourth pass roughly corresponded to the initial activity. In the second regeneration performed between the second pass and the third pass, an unexpectedly large amount of coke is burned, resulting in a catalyst bed temperature of the desired maximum temperature of 490 ° C. over 40 minutes. And reached a high temperature of 550 ° C. Thereby, as shown in Table 1, the yield of propylbenzene was increased by an order of magnitude. However, as is clear from the experimental studies described herein, zeolite beta formulated with a silica binder is much more stable and substantially better regenerated than the corresponding zeolite beta formulated with an alumina binder. The coefficient is shown.
[0033]
[Table 1]

[0034]
As stated above, in accordance with the present invention, the silica binder zeolite beta catalyst is designed to be suitable for use in liquid phase alkylation. In the practice of the present invention, the alkylation reaction is carried out at a pressure sufficiently higher than the vapor pressure exhibited by the aromatic substrate at the reaction temperature used for the purpose of ensuring that the liquid phase is maintained throughout the reaction vessel. In order to ensure a complete liquid phase reaction, a flooded bed format is used in which the catalyst is completely immersed in the liquid. This can be easily achieved using upflow techniques such as those used in the experimental studies shown above, which will generally be suitable for use in the practice of the present invention. However, it is also possible to achieve downflow overflow operation by controlling the outlet flow rate to ensure that the catalyst bed is covered with liquid benzene or other aromatic substrate.
[0035]
Preferably, a stepwise reaction to ensure good solubility of ethylene (or other alkylating agent) in benzene (or other aromatic substrate) and to ensure that the entire reaction occurs in the liquid phase. The format (staged reaction format) is used. As disclosed in Butler, U.S. Pat. No. 5,073,653, described above, by using a series of sequentially connected reactors and mounting multiple catalyst beds in a single reactor, the Such a step-wise reaction format can be provided. When a plurality of stages are provided, it is possible to obtain an opportunity to perform interstage cooling when using an adiabatic reaction tank, or it is possible to use several isothermal reaction stages. Referring now to FIG. 3, there is shown a schematic diagram of a staged reaction vessel apparatus used when producing ethylbenzene by the reaction of ethylene and benzene, which has an adiabatic reaction vessel with interstage cooling and ethylene injection. Multiple are included. More specifically, as shown in this figure, ethylene and benzene are fed to the inlet line 15 of the dehydrator 16 via lines 12 and 14. This dehydrator has the function of essentially drying the input charged to the alkylation reactor, preferably dehydrating so that the water content is less than 100 ppm, more preferably less than 50 ppm. Fulfill. By way of example, the dehydrator 16 may take the form of a packed tower or an azeotropic drying column filled with a desiccant such as silica gel or other suitable hygroscopic medium.
[0036]
The dehydrator effluent is fed to reaction vessel 18, ie, the first reaction vessel in a plurality of serially connected alkylation reactors operated in an upflow mode. The reaction vessel 18 is operated at an average temperature of 350 ° C. or less, preferably an average temperature in the range of 150-250 ° C. For liquid phase operation, the pressure in the reaction vessel 18 is sufficient to keep the benzene in the liquid phase, preferably at least 50 psi higher than the vapor pressure indicated by the reaction vessel temperature. The reactor pressure is typically in the range of about 500-850 psia. The remaining reaction vessels located downstream are usually operated under substantially the same conditions as the first reaction vessel. The effluent from the first reaction vessel 18 is removed via line 19 and passed through a heat exchanger 22 to be supplied to the second reaction vessel 24, whereby the second stage is obtained by the heat exchanger 22. The effluent before being sent to the reaction tank 24 is cooled. Ethylene is fed via line 21 and mixed with the effluent coming out of the first reactor 18. Preferably, as shown in this figure, ethylene is fed into the reaction vessel before the effluent leaving the reaction vessel is cooled for the purpose of promoting the distribution of ethylene throughout the liquid benzene. . This cooling step is preferably performed so that the temperature of the feed mixture fed to the second reaction vessel 24 is lowered until it is approximately the same as the inlet temperature value of the first reaction vessel 18. Usually, the average temperature of the second reaction tank is made substantially the same as the average temperature of the first reaction tank. In order for the pressure gradient to be sufficient to accommodate the flow through the device, its pressure needs to be somewhat lower. The effluent discharged from the second reaction tank 24 is fed to the second interstage cooling device 29 together with ethylene supplied via the line 27, and the cooling mixture causes the charged mixture to the third reaction tank 30 to be again supplied to the first reaction tank 30. The two reactors are cooled to a temperature almost equal to the inlet temperature.
[0037]
The product exiting from the reaction tank 30 is sent via a line 32 to a separation processing device 34 located downstream. Ethylbenzene is separated in apparatus 34 and removed as the product of the alkylation plant. Ethylbenzene is typically used as a feed to a dehydrogenation unit where ethylbenzene is catalytically dehydrogenated in the production of styrene. Benzene and ethylene are usually separated in apparatus 34 and reused in the alkylation process. Heavier polyethylbenzene may be transalkylated with benzene to produce additional ethylbenzene. A multi-stage separation apparatus suitable for use with an alkyl exchange apparatus is an integrated apparatus disclosed in the above-mentioned European Patent Application No. 467,007, the disclosure of which is hereby incorporated by reference in its entirety. It may take one of the forms. For the purpose of improving the selectivity of monoalkylation, the amount of benzene contained in the feed material fed to the alkylation reaction tank is made a stoichiometric excess with respect to ethylene. If the reactor is operated such that liquid phase alkylation occurs under relatively mild conditions, not only will the amount of xylene produced in the alkylation reaction be minimized, but the molar ratio of benzene / ethylene is usually reduced. It is also possible to make it somewhat lower than the molar ratio used. A commonly used benzene / ethylene molar ratio is about 4: 1, but it is also possible to use a lower molar ratio such as about 2: 1. However, there is generally little motivation to use extremely high ratios, and as a practical matter, the benzene / ethylene molar ratio will rarely exceed 15: 1. A preferred benzene / ethylene molar ratio is about 4/1. The benzene / ethylene molar ratios shown above are those for the entire apparatus and multistage reactors, such as the apparatus shown in the figure, and the benzene / ethylene ratio of the feed fed to each stage is less than the overall ratio. I will. The amount of ethylene dissolved in the benzene charge fed to each reactor stage will depend in part on the number of reactor stages used. Usually, as shown, at least three reactor stages will be used. Even if additional reactor stages are provided, the total number of stages will usually not exceed 8. The pressure in each reaction stage and the amount of ethylene fed to each reaction stage are preferably at a pressure and quantity such that at least 1 mole percent of ethylene is dissolved in benzene. Usually, at least 2 mole percent of ethylene is dissolved in the charge fed to each reactor. Unless a large number of reactor stages are used, the amount of ethylene dissolved in the benzene liquid phase of each reactor is generally at least 4 mole percent.
[0038]
It is also possible to carry out the multistage ethylation of benzene using isothermal reaction zones according to the invention. The isothermal reactor may take the form of a shell and tube type heat exchanger, in which case the alkylating catalyst is placed in the tube and the heat transfer medium is located around the tube filled with the catalyst. It may be circulated through the shell. Of course, the heat exchanger medium is fed through the reaction vessel at a feed rate such that the temperature is maintained relatively constant throughout each reaction stage. In this case it will not be necessary to perform interstage cooling, but it may be preferred to inject ethylene in front of each reaction stage.
[0039]
As indicated above, it is preferred that the beta-silica catalyst be used in a liquid phase alkylation reaction under relatively mild conditions. However, the present invention operates in the supercritical range by using the benzene substrate under severe conditions where both temperature and pressure are higher than the critical temperature and critical pressure of benzene (thereby allowing the alkylation reactor to be quasi-liquid). It is also possible to carry out by operating in phase. As indicated above, in that case the alkylation reactor would be operated at temperatures above about 290 ° C. and pressures above 700 psia. Usually a somewhat higher temperature and a somewhat higher pressure will be used. Here, the operation of the alkylation reactor using benzene in the supercritical range will be in the range of 300-600 ° C. and in the range of about 650-850 psia.
[0040]
While specific embodiments of the invention have been described, all such modifications are within the scope of the appended claims, as such modifications may occur to those skilled in the art. It will be understood that it is intended to protect.
[0041]
The features and aspects of the present invention are as follows.
[0042]
1.
(A) an alkylating zeolite which is fed with a benzene-containing feedstock into the reaction zone and which is blended with a silica binder and exhibits an average regeneration factor of at least 95% when regeneration is carried out at least three times at temperatures below 500 ° C. Contacting a molecular sieve catalyst comprising a beta catalyst;
(B) C ₂ -C _Four Feeding an alkylating agent to the reaction zone;
(C) operating the reaction zone under temperature and pressure conditions effective to effect alkylation of the benzene with the alkylating agent in the liquid phase or in the supercritical range; and
(D) recovering the alkylated benzene from the reaction zone;
An aromatic alkylation process comprising:
[0043]
2. The method of claim 1, wherein the alkylating agent is an ethylating agent.
[0044]
3. The method of claim 2 wherein the ethylating agent is ethylene.
[0045]
4). A process according to claim 1 wherein the reaction zone is operated under temperature and pressure conditions where the benzene is present in the liquid phase.
[0046]
5. The method of claim 4 wherein the benzene and alkylating agent are fed to the reaction zone at a flow rate such that the molar ratio of benzene to the alkylating agent is less than 15.
[0047]
6). 6. The method of claim 5, wherein the molar ratio of the benzene to the alkylating agent is less than 10.
[0048]
7). 6. A process according to claim 5, wherein the molar ratio of benzene to alkylating agent is in the range of 4-10.
[0049]
8).
(A) feeding a benzene-containing feed to the reaction zone and contacting it with a molecular sieve catalyst comprising an alkylating zeolite beta catalyst formulated with a silica binder;
(B) supplying ethylene to the reaction zone;
(C) operating the reaction zone under temperature and pressure conditions where benzene is present in the liquid phase or supercritical phase and ethylation of the benzene occurs in the presence of the alkylating catalyst during primary activity. ,
(D) recovering an alkylated product containing ethylbenzene from the reaction zone;
(E) continuing operation of the reaction zone until the activity of the catalyst with respect to ethylation of benzene decreases by a value of 0.1% from the primary activity of the catalyst with respect to ethylation of benzene;
(F) providing a regeneration procedure that stops operation of the reaction zone for benzene alkylation and performs regeneration of the catalyst in an oxidizing environment such that the average temperature during the regeneration process is 500 ° C. or less;
(G) After the regeneration procedure, the operation of the alkylation reaction zone is provided again by supplying benzene to the alkylation reaction zone;
(H) the ethylation of the benzene in the liquid phase such that the ethylation of the benzene occurs in the reaction zone with a secondary activity of at least 95% of the primary activity in the presence of the regenerated catalyst to produce ethylbenzene; Operating under temperature and pressure conditions effective to occur in the supercritical phase,
(I) continuing operation of the alkylation reaction zone until the activity of the catalyst for ethylation of benzene drops to a degree of at least 0.1% of the secondary activity;
(J) regenerating the catalyst by stopping operation of the alkylation reaction zone and regenerating the catalyst in an oxidizing environment at an average temperature of 500 ° C. or less;
(K) supplying benzene and ethylene to the alkylation reaction zone; and
(L) the ethylation of the benzene in the liquid phase such that the ethylation of the benzene in the presence of the regenerated catalyst gives at least 95% of the secondary activity in the reaction zone Operating under temperature and pressure conditions effective to occur in the supercritical phase,
A process for producing ethylbenzene comprising:
[0050]
9. 9. The method of claim 8, wherein the zeolite beta catalyst comprises zeolite beta modified with lanthanum in which lanthanum ions are incorporated into the zeolite beta by ion exchange.
[0051]
10. The method of claim 8 wherein the zeolite beta has a silica / aluminum ratio of at least 40.
[0052]
11. 9. The method of claim 8, wherein the zeolite beta catalyst comprises a modified zeolite beta having an in-growth ZSM-12 crystal framework within the crystal structure of zeolite beta.
[0053]
12 The regeneration coefficient exhibited by the zeolite beta after at least 3 regenerations is at least 105 of the regeneration coefficient value exhibited by a zeolite beta catalyst formulated with an alumina binder in the same amount as the silica binder used with the zeolite beta. The method according to claim 8, which is%.
[0054]
13. 9. A process according to claim 8 wherein the reaction zone is operated under temperature and pressure conditions where the benzene is present in the liquid phase.
[0055]
14 14. The method of claim 13, wherein the benzene and alkylating agent are fed to the reaction zone at a flow rate such that the molar ratio of benzene to alkylating agent is less than 15.
[0056]
15. 15. The method of claim 14, wherein the molar ratio of the benzene to the alkylating agent is less than 10.
[0057]
16. 15. A process according to claim 14 wherein the molar ratio of benzene to alkylating agent is in the range of 4-10.
[Brief description of the drawings]
FIG. 1 is a graph showing the catalyst bed volume percent at the highest temperature under liquid phase alkylation conditions using a zeolite beta catalyst formulated with an alumina binder.
FIG. 2 shows the highest alkylation temperature under progressive liquid phase conditions when the benzene / ethylene molar ratio is progressively reduced using a regenerated zeolite beta catalyst formulated with a silica binder. Figure 5 is a graph showing the volume percent of catalyst bed at the time.
FIG. 3 is a schematic diagram of a staged reactor apparatus that can be used in the practice of the present invention.

Claims (2)

(A) an alkylating zeolite which is fed with a benzene-containing feedstock into the reaction zone and which is blended with a silica binder and exhibits an average regeneration factor of at least 95% when regeneration is carried out at least three times at temperatures below 500 ° C. Contacting a molecular sieve catalyst comprising a beta catalyst;
(B) supplying a C ₂ -C ₄ alkylating agent to said reaction zone,
(C) operating the reaction zone under temperature and pressure conditions effective to effect alkylation of the benzene with the alkylating agent in the liquid phase or in the supercritical range; and (d) the alkylated benzene is Recover from the reaction zone,
An aromatic alkylation process comprising: (A) feeding a benzene-containing feed to the reaction zone and contacting it with a molecular sieve catalyst comprising an alkylating zeolite beta catalyst formulated with a silica binder;
(B) supplying ethylene to the reaction zone;
(C) operating the reaction zone under temperature and pressure conditions where benzene is present in the liquid phase or supercritical phase and ethylation of the benzene occurs in the presence of the alkylating catalyst during primary activity. ,
(D) recovering an alkylated product containing ethylbenzene from the reaction zone;
(E) continuing operation of the reaction zone until the activity of the catalyst with respect to ethylation of benzene decreases by a value of 0.1% from the primary activity of the catalyst with respect to ethylation of benzene;
(F) providing a regeneration procedure that stops operation of the reaction zone for benzene alkylation and performs regeneration of the catalyst in an oxidizing environment such that the average temperature during the regeneration process is 500 ° C. or less;
(G) After the regeneration procedure, the operation of the alkylation reaction zone is provided again by supplying benzene to the alkylation reaction zone;
(H) the ethylation of the benzene in the liquid phase such that the ethylation of the benzene occurs in the reaction zone with a secondary activity of at least 95% of the primary activity in the presence of the regenerated catalyst to produce ethylbenzene; Operating under temperature and pressure conditions effective to occur in the supercritical phase,
(I) continuing operation of the alkylation reaction zone until the activity of the catalyst for ethylation of benzene drops to a degree of at least 0.1% of the secondary activity;
(J) regenerating the catalyst by stopping operation of the alkylation reaction zone and regenerating the catalyst in an oxidizing environment at an average temperature of 500 ° C. or less;
(K) benzene and ethylene are fed to the alkylation reaction zone, and (l) the reaction zone has an initial activity for ethylation of the benzene in the presence of the regenerated catalyst and the initial activity for the ethylation of the benzene is the secondary activity. Operating under temperature and pressure conditions effective for the ethylation of the benzene to occur in the liquid phase or supercritical phase to give at least 95%;
A process for producing ethylbenzene comprising:

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