(JP6198132-A)      Removal of nitrogen oxide from exhaust comprises contacting exhausts contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a total pore vol. of 0.48-1.2 cm3 g-1 with 0.26-0.6 cm3 g-1 of pores not greater than 80 A in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    Also claimed is a process for removing nitrogen oxide from exhaust which comprises contacting the exhaust contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a pore vol. of pores not greater than 60 A of 0.06-0.2 cm3 g-1 and a pore vol. of pores less than 80 A of 0.1-0.26 cm3 g-1 in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    USE/ADVANTAGE -   To remove nitrogen oxide cpds. from exhaust systems including a diesel engine. It has a high NOx redn. removal efficiency at a lower temp. There is also less variation in the NOx removal efficiency. The alumina catalyst is able to accelerate the moderate oxidn. of the reducing agent.    (JP7136466-A)      Removal of nitrogen oxide from exhaust comprises contacting exhausts contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a total pore vol. of 0.48-1.2 cm3 g-1 with 0.26-0.6 cm3 g-1 of pores not greater than 80 A in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    Also claimed is a process for removing nitrogen oxide from exhaust which comprises contacting the exhaust contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a pore vol. of pores not greater than 60 A of 0.06-0.2 cm3 g-1 and a pore vol. of pores less than 80 A of 0.1-0.26 cm3 g-1 in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    USE/ADVANTAGE -   Used to remove nitrogen oxide cpds. from exhaust systems including a diesel engine. It has a high NOx redn. removal efficiency at a lower temp. There is also less variation in the NOx removal efficiency. The alumina catalyst is able to accelerate the moderate oxidn. of the reducing agent.    (JP7171347-A)      Removal of nitrogen oxide from exhaust comprises contacting exhausts contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a total pore vol. of 0.48-1.2 cm3 g-1 with 0.26-0.6 cm3 g-1 of pores not greater than 80 A in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    Also claimed is a process for removing nitrogen oxide from exhaust which comprises contacting the exhaust contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a pore vol. of pores not greater than 60 A of 0.06-0.2 cm3 g-1 and a pore vol. of pores less than 80 A of 0.1-0.26 cm3 g-1 in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    USE/ADVANTAGE -   Used to remove nitrogen oxide cpds. from exhaust systems including a diesel engine. It has a high NOx redn. removal efficiency at a lower temp. There is also less variation in the NOx removal efficiency. The alumina catalyst is able to accelerate the moderate oxidn. of the reducing agent.    (JP2847021-B2)      Removal of nitrogen oxide from exhaust comprises contacting exhausts contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a total pore vol. of 0.48-1.2 cm3 g-1 with 0.26-0.6 cm3 g-1 of pores not greater than 80 A in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    Also claimed is a process for removing nitrogen oxide from exhaust which comprises contacting the exhaust contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a pore vol. of pores not greater than 60 A of 0.06-0.2 cm3 g-1 and a pore vol. of pores less than 80 A of 0.1-0.26 cm3 g-1 in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    USE/ADVANTAGE -   Used to remove nitrogen oxide cpds. from exhaust systems including a diesel engine. It has a high NOx redn. removal efficiency at a lower temp. There is also less variation in the NOx removal efficiency. The alumina catalyst is able to accelerate the moderate oxidn. of the reducing agent.    (US5853679-A)      Removal of nitrogen oxide from exhaust comprises contacting exhausts contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a total pore vol. of 0.48-1.2 cm3 g-1 with 0.26-0.6 cm3 g-1 of pores not greater than 80 A in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    Also claimed is a process for removing nitrogen oxide from exhaust which comprises contacting the exhaust contg. nitrogen oxide with an alumina catalyst contg. not more than 0.5 wt.% of an alkali metal and/or an alkaline earth metal. It has a pore vol. of pores not greater than 60 A of 0.06-0.2 cm3 g-1 and a pore vol. of pores less than 80 A of 0.1-0.26 cm3 g-1 in an oxidative atmosphere contg. excess oxygen in the presence of a hydrocarbon or an oxygen-contg. organic cpd.    USE/ADVANTAGE -   Used to remove nitrogen oxide cpds. from exhaust systems including a diesel engine. It has a high NOx redn. removal efficiency at a lower temp. There is also less variation in the NOx removal efficiency. The alumina catalyst is able to accelerate the moderate oxidn. of the reducing agent.