Process for producing methyl methacrylate

A paving block and a paving block assembly include a prism-shaped paving block body having a top surface, a bottom surface disposed opposite the top surface and a first pair of opposing side walls and a second pair of opposing side walls. The first and second pair of opposing side walls are disposed between the top and bottom surfaces with respective ones of the first pair of opposing side walls and the second pair of opposing side walls connected perpendicularly to each other. The top surface has a plurality of longitudinal grooves which are formed therein and extend parallel to each other. Each one of the plurality of grooves has a width substantially equal to each other. The paving block body has at least one projection connected to one of the side walls and positioned between the top and bottom surfaces. The at least one projection projects from the one side wall a distance equal to or substantially equal to the width of the grooves.

Paving block and its installation method

PROBLEM TO BE SOLVED: To provide a movement prevention means for fluid conduits capable of preventing relative movement of a socket end and a spigot end nearly equally in both directions along the axes of the conduits SOLUTION: The movement prevention means comprises an engagement portion 20 to engage with an outer surface of the fluid conduit 11, a recess portion 16 opened toward the outer surface of the fluid conduit 11 and receiving the engagement portion 20 therein, a hook portion 15a extended over a pressing ring 13 so as to be engageable with an extension portion 5a of the socket end 5, and a stopper portion 15b extended contactably with the socket end 5 or the pressing ring 13 The engagement portion 20 includes a first claw 20a to engage with the outer surface of the fluid conduit 11 and a second claw 20b arranged apart from the first claw 20a in the direction of the conduit axis C so as to engage with the outer surface of the fluid conduit 11 The first claw 20a and the second claw 20b are formed generally symmetrically with respect to an orthogonal plane D substantially orthogonal to the conduit axis C The engagement portion 20 is received in the recess portion 16 inclinedly so that the first claw 20a or the second claw 20b bites into the outer surface of the fluid conduit 11 COPYRIGHT: (C)2008,JPO&INPIT

Movement prevention means for fluid conduit

The invention relates to a method for producing a carboxylic acid amide from a carbonyl compound and hydrocyanic acid, comprising the steps of A) reacting a carbonyl compound with hydrocyanic acid to produce a hydroxycarboxylic acid nitrile, B) hydrolysis of the hydroxycarboxylic acid nitrile obtained in step A) in the presence of a catalyst comprising manganese dioxide, wherein a molar excess of carbonyl compound is used in relation to the hydrocyanic acid to react the carbonyl compound with hydrocyanic acid according to step A), and the reaction mixture obtained in step A) is not purified by distillation before the hydrolysis according to step B) is carried out. The invention furthermore relates to a method for producing alkyl(meth)acrylates from polymers, moulding compounds and moulded bodies, wherein a method for producing a carboxylic acid amide from a carbonyl compound and hydrocyanic acid is carried out in accordance with the method described above.

Method for producing a carboxylic acid amide from a carbonyl compound and hydrocyanic acid

PURPOSE: To obtain the titled substance inexpensively and simply, by reacting propionic acid with methylal in a gaseous phase by the use of a calcined solid phosphate catalyst and bringing a formed mixture to a silica catalyst containing an alkali metal of group I of the periodic table immediately. CONSTITUTION: Propionic acid is reacted with methylal in a gaseous phase by the use of a solid phosphate catalyst calcined at high temperature of 500W1,000°C and a formed gas containing formaldehyde, methanol and methyl propionate is immediately brought into contact with an alkali metal of Group I of the periodic table to give the titled substance. The solid phosphate catalyst, for example, is prepared by a method wherein a solution obtained by diluting 85% phosphoric acid sold on the market in water is sprayed upon a carrier (e.g. silica gel of alumina) and preferably previously calcining the carrier at ≤300°C before high-temperature calcination is carried out. The catalyst of the second stage is preferably that obtained by supporting an alkali metallic compound on a porous amorphous silica. COPYRIGHT: (C)1988,JPO&Japio

Production of methyl methacrylate

PURPOSE:To produce the titled compound in high yield, by hydrating acetone cyanhydrin produced from cyanic acid and acetone, reacting the hydration product with carbon monoxide and methanol, and dehydrating formamide produced as a by-product and recycling in the form of cyanic acid to the raw material system. CONSTITUTION:Cyanic acid is made to react with acetone in the reactor 40, and the resultant acetone cyanhydrin (ACH) is hydrated in the hydration reactor 5 to produce alpha-hydroxyisobutyramide, which is extracted from the bottom of the column 7 for the separation of low-boiling component. The obtained amide is made to react with carbon monoxide and methanol in the irrigated column reactor 12, and the produced methyl alpha-hydroxyisobutyrate and formamide are separated from each other with the separation column 24. The methyl alpha-hydroxyisobutyrate obtained from the column top is dehydrated in the dehydration reaction column 26, and the obtained methyl methacrylate is taken out of the system from the line 29. The formamide obtained from the column bottom is dehydrated in the dehydration column 32, and the produced cyanic acid is recycled through the line 35 to the ACH-synthesizing system.

Aoyama Tetsuo

Papers

Production of methyl methacrylate