METHOD FOR SYNTHESIZING UREA, HYDROGEN STORAGE METHOD, METHOD FOR PRODUCING SILICA PARTICLES, AND HEAT STORAGE METHOD

• Main Authors: UMEGAKI TETSUJI, KANEKO TAKEHIRO
• Format: Patent
• Language: English; Japanese
• Published: 16.02.2024
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; ADHESIVES; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOUNDS THEREOF; DYES; INORGANIC CHEMISTRY; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; NON-METALLIC ELEMENTS; ORGANIC CHEMISTRY; PAINTS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POLISHES; THEIR RELEVANT APPARATUS; TRANSPORTING

To provide a method for synthesizing urea that enables synthesis at lower temperatures and low pressures, a method for producing silica particles that can be suitably used in the method for synthesizing urea, a hydrogen storage method using the silica particles, and a heat storage method.SOLUTION: A method for synthesizing urea includes an introduction step for introducing carbon dioxide and ammonia into pores of porous silica particles, and a pressurization step for pressurizing the porous silica particles with carbon dioxide and ammonia introduced into their pores. The porous silica particles have a peak pore size of 2.4-4.0 nm. In the porous silica particles, volume of pores ranging from 1.8 to 4.3 nm constitutes 50-90% of total pore volume.SELECTED DRAWING: None 【課題】より低温・低圧の条件で合成が可能な尿素の合成方法、該尿素の合成方法に好適に使用が可能な、シリカ粒子の製造方法、並びに、該シリカ粒子を用いる、水素の貯蔵方法、及び、蓄熱方法を提供する。【解決手段】二酸化炭素及びアンモニアを、多孔質シリカ粒子の細孔内に導入する導入工程と、前記多孔質シリカ粒子の細孔内に二酸化炭素及びアンモニアが導入されたシリカ粒子を加圧する加圧工程と、を備え、前記多孔質シリカ粒子のピーク細孔径が、２．４～４．０ｎｍであり、前記多孔質シリカ粒子の、全細孔容積に対する１．８～４．３ｎｍの細孔容積の割合が、５０～９０％である、尿素の合成方法。【選択図】なし